FERTILITY

Fertility is the natural capability of giving life. As a measure, "fertility rate" is the number of children born per couple, person or population. This is different from fecundity, which is defined as the potential for reproduction (influenced by gamete production, fertilisation and carrying a pregnancy to term). Infertility is a deficient fertility.

Human fertility depends on factors of:

• nutrition,
  
• sexual behavior,
  
• culture,
  
• instinct,
  
• endocrinology,
  
• timing,
  
• economics,
  
• way of life, and
  
• emotions.

Human fertility

Both women and men have hormonal cycles which determine both when a woman can achieve pregnancy and when a man is most virile. The female cycle is approximately twenty-eight days long, but the male cycle is variable. Men can ejaculate and produce sperm at any time of the month, but their sperm quality dips occasionally, which scientists guess is in relation to their internal cycle.

Furthermore, age also plays a role, especially for women.

Menstrual cycle

Although women can become pregnant at any time during their menstrual cycle, peak fertility occurs during just a few days of the cycle: usually two days before and two days after the ovulation date^[3]. This fertile window, varies from woman to woman, just as the ovulation date often varies from cycle to cycle for the same woman^[4]. The ovule is usually capable of being fertilized for up to 48 hours after it is released from the ovary. Sperm survive inside the uterus between 48 to 72 hours on average, with the maximum being 120 hours (5 days).

These periods and intervals are important factors for couples using the rhythm method of contraception.

Female fertility

The average age of menarche in the United States is about 12.5 years.^[5] In postmenarchal girls, about 80% of the cycles were anovulatory in the first year after menarche, 50% in the third and 10% in the sixth year.^[6][7] Women's fertility peaks around the age of 19-24, and often declines after 30.^{[citation needed]} With a rise in women postponing pregnancy,^[8] this can create an infertility problem. Of women trying to get pregnant, without using fertility drugs or in vitro fertilization:

• At age 30, 75% will get pregnant within one year, and 91% within four years.
• At age 35, 66% will get pregnant within one year, and 84% within four years.
• At age 40, 44% will get pregnant within one year, and 64% within four years.^[9]

The above figures are for pregnancies ending in a live birth and take into account the increasing rates of miscarriage in the aging population. According to the March of Dimes, "about 9 percent of recognised pregnancies for women aged 20 to 24 ended in miscarriage. The risk rose to about 20 percent at age 35 to 39, and more than 50 percent by age 42".^[10]

Birth defects, especially those involving chromosome number and arrangement, also increase with the age of the mother. According to the March of Dimes, "At age 25, a woman has about a 1-in-1,250 chance of having a baby with Down syndrome; at age 30, a 1-in-1,000 chance; at age 35, a 1-in-400 chance; at age 40, a 1-in-100 chance; and at 45, a 1-in-30 chance."^[11]

The use of fertility drugs and/or invitro fertilization can increase the chances of becoming pregnant at a later age. Successful pregnancies facilitated by fertility treatment have been documented in women as old as 67.^[12]

Doctors recommend that women over 30 who have been unsuccessful in trying to conceive for more than 6 months undergo some kind of fertility testing.^[13]

Male fertility and age

Erectile dysfunction increases with age,^[14] but fertility does not decline in men as sharply as it does in women. There have been examples of males being fertile at 94 years old.^[14] However, evidence suggests that increased male age is associated with a decline in semen volume, sperm motility, and sperm morphology.^[15] In studies that controlled for female age, comparisons between men under 30 and men over 50 found relative decreases in pregnancy rates between 23% and 38%.^[15]

Cause of decline

Sperm count declines with age, with men aged 50-80 years producing sperm at an average rate of 75% compared with men aged 20-50 years. However, an even larger difference is seen in how many of the seminiferous tubules in the testes contain mature sperm;

• In males 20-39 years old, 90% of the seminiferous tubules contain mature sperm.
• In males 40-69 years old, 50% of the seminiferous tubules contain mature sperm.
• In males 80 years old and older, 10% of the seminiferous tubules contain mature sperm.^[14]

Recent research has suggested increased risks for health problems for children of older fathers. A large scale Israeli study found that the children of men 40 or older were 5.75 times more likely than children of men under 30 to have an autism spectrum disorder, controlling for year of birth, socioeconomic status, and maternal age.^[16] Increased paternal age has also been correlated to schizophrenia in numerous studies.^[17][18][19]

The American Fertility Society recommends an age limit for sperm donors of 50 years or less,^[20] and many fertility clinics in the United Kingdom will not accept donations from men over 40 or 45 years of age. ^[21] In part because of this fact, more women are now using a take-home baby rate calculator to estimate their chances of success following invitro fertilization. ^[22]

References

1. http://www.gfmer.ch/Books/Reproductive_health/The_demography_of_fertility_and_infertility.html
2. http://www.enotes.com/public-health-encyclopedia/fecundity-fertility
3. http://www.duofertility.com/en/my-body/my-cycle/my-fertile-period.html
4. Creinin MD, Keverline S, Meyn LA (October 2004). "How regular is regular? An analysis of menstrual cycle regularity". Contraception 70 (4): 289–92. doi:10.1016/j.contraception.2004.04.012. PMID 15451332.
5. Anderson SE, Dallal GE, Must A (April 2003). "Relative weight and race influence average age at menarche: results from two nationally representative surveys of US girls studied 25 years apart". Pediatrics 111 (4 Pt 1): 844–50. doi:10.1542/peds.111.4.844. PMID 12671122. http://pediatrics.aappublications.org/cgi/content/full/111/4/844?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&searchid=1&FIRSTINDEX=0&minscore=5000&resourcetype=HWCIT.
6. Apter D (February 1980). "Serum steroids and pituitary hormones in female puberty: a partly longitudinal study". Clin. Endocrinol. (Oxf) 12 (2): 107–20. doi:10.1111/j.1365-2265.1980.tb02125.x. PMID 6249519.
7. Apter D (February 1980). "Serum steroids and pituitary hormones in female puberty: a partly longitudinal study". Clin. Endocrinol. (Oxf) 12 (2): 107–20. doi:10.1111/j.1365-2265.1980.tb02125.x. PMID 6249519. http://www3.interscience.wiley.com/journal/119590594/abstract.
8. http://findarticles.com/p/articles/mi_m1077/is_1_62/ai_n16807720 "Late-in-life Pregnancy"
9. "Fertility Treatment Less Successful After 35". WebMD. http://www.webmd.com/content/article/89/100183.htm. Retrieved on July 4 2006.
10. "Pregnancy After 35". March of Dimes. http://www.marchofdimes.com/professionals/14332_1155.asp. Retrieved on May 21 2008.
11. "The sterility tax can be reestablished in Russia". http://russia-ic.com/business_law/in_depth/253/. Retrieved on September 22 2006.
12. "Spanish woman ' is oldest mother'". BBC News. http://news.bbc.co.uk/2/hi/health/6220523.stm. Retrieved on 2006-12-30.
13. Female Fertility Testing
14. ^{a b c} Effect of Age on Male Fertility Seminars in Reproductive Endocrinology. Volume, Number 3, August 1991. Sherman J. Silber, M.D.
15. ^{a b} Kidd SA, Eskenazi B, Wyrobek AJ (February 2001). "Effects of male age on semen quality and fertility: a review of the literature". Fertil. Steril. 75 (2): 237–48. doi:10.1016/S0015-0282(00)01679-4. PMID 11172821. http://linkinghub.elsevier.com/retrieve/pii/S0015-0282(00)01679-4.
16. Reichenberg A, Gross R, Weiser M, et al. (September 2006). "Advancing paternal age and autism". Arch. Gen. Psychiatry 63 (9): 1026–32. doi:10.1001/archpsyc.63.9.1026. PMID 16953005. http://archpsyc.ama-assn.org/cgi/content/abstract/63/9/1026.
17. Malaspina D, Harlap S, Fennig S, et al. (April 2001). "Advancing paternal age and the risk of schizophrenia". Arch. Gen. Psychiatry 58 (4): 361–7. doi:10.1001/archpsyc.58.4.361. PMID 11296097. http://archpsyc.ama-assn.org/cgi/pmidlookup?view=long&pmid=11296097.
18. Sipos A, Rasmussen F, Harrison G, et al. (November 2004). "Paternal age and schizophrenia: a population based cohort study". BMJ 329 (7474): 1070. doi:10.1136/bmj.38243.672396.55. PMID 15501901.
19. Malaspina D, Corcoran C, Fahim C, et al. (April 2002). "Paternal age and sporadic schizophrenia: evidence for de novo mutations". Am. J. Med. Genet. 114 (3): 299–303. doi:10.1002/ajmg.1701. PMID 11920852.
20. Plas E, Berger P, Hermann M, Pflüger H (August 2000). "Effects of aging on male fertility?". Exp. Gerontol. 35 (5): 543–51. doi:10.1016/S0531-5565(00)00120-0. PMID 10978677. http://linkinghub.elsevier.com/retrieve/pii/S0531-5565(00)00120-0.
21. Age Limit of Sperm Donors in the United Kingdom Pdf file
22. http://www.formyodds.com

Reviewed by Bambang Widjanarko Obstetrician & Gynecologist

HUMAN FERTILIZATION

Human fertilization is the union of a human egg and sperm, usually occurring in the ampulla of the fallopian tube. It is also the initiation of prenatal development. Scientists discovered the dynamics of human fertilization in the nineteenth century.

Fertilization (also known as conception, fecundation and syngamy), is the fusion of gametes to produce a new organism. The process involves a sperm fusing with an ovum, which eventually leads to the development of an embryo.

It is when first of all the acrosome at the head tip produces enzymes, which cuts through the outer jelly coat of the egg. After that has happened, the sperm plasma fuses with the egg’s plasma membrane. Finally, the Head disconnects with the body, and the egg can now travel down the Fallopian tube to reach the womb, where the baby grows.

Fertilization may or may not involve sexual intercourse. In vitro fertilisation (IVF) is a process by which egg cells are fertilized by sperm outside the womb, in vitro. Sperm is propelled through the female reproductive tract by flagellation and may get through the jelly coat through a process called sperm activation. The oocyte and sperm fuse once the sperm is through the corona radiata and the zona pellucida; two layers covering and protecting the oocyte from fertilization by more than one sperm.

Corona radiata

Human ovum examined fresh in the liquor folliculi. The zona pellucida is seen as a thick clear girdle surrounded by the cells of the corona radiata. The egg itself shows a central granular deutoplasmic area and a peripheral clear layer, and encloses the germinal vesicle, in which is seen the germinal spot.

The egg binds the sperm through the corona radiata, a layer of follicle cells on the outside of the secondary oocyte. Fertilization is when the nuclei of a sperm and an egg fuse. The successful fusion of gametes form a new organism

Acrosome reaction

The acrosome reaction must occur to mobilise enzymes within the head of the spermatozoon to degrade the zona pellucida.

Zona pellucida

The sperm then reaches the zona pellucida, which is an extra-cellular matrix of glycoproteins. A special complementary molecule on the surface of the sperm head then binds to a ZP3 glycoprotein in the zona pellucida. This binding triggers the acrosome to burst, releasing enzymes that help the sperm get through the zona pellucida.

Some sperm cells consume their acrosome prematurely on the surface of the egg cell, facilitating for other surrounding sperm cells, having on average 50% genome similarity, to penetrate the egg cell. It may be regarded as a mechanism of kin selection.

Cortical reaction

Once the sperm cells find their way past the zona pellucida, the cortical reaction occurs: cortical granules inside the secondary oocyte fuse with the plasma membrane of the cell, causing enzymes inside these granules to be expelled by exocytosis to the zona pellucida. This in turn causes the glyco-proteins in the zona pellucida to cross-link with each other, making the whole matrix hard and impermeable to sperm. This prevents fertilization of an egg by more than one sperm.

Fusion

The sperm fuses with the oocyte, enabling fusion of their genetic material, in turn.

Cell membranes

The cell membranes of the secondary oocyte and sperm fuse together.

Transformations

Both the oocyte and the sperm go through transformations, as a reaction to the fusion of cell membranes, preparing for the fusion of their genetic material.

The oocyte now completes its second meiotic division. This results in a mature ovum. The nucleus of the oocyte is called a pronucleus in this process, to distinguish it from the nuclei that are the result of fertilization.

Diagram showing the reduction in number of the chromosomes in the process of maturation of the ovum.

Second meiotic division :

Events involving meiosis, showing chromosomal crossover

The sperm's tail and mitochondria degenerate with the formation of the male pronucleus. This is why all mitochondria in humans are of maternal origin.

Replication

The pronuclei migrate toward the center of the oocyte, rapidly replicating their DNA as they do so to prepare the new human for its first mitotic division.

Mitosis

The male and female pronuclei don't fuse, although their genetic material do so. Instead, their membranes dissolve, leaving no barriers between the male and female chromosomes. During this dissolution, a mitotic spindle forms around them to catch the chromosomes before they get lost in the egg cytoplasm. By subsequently performing a mitosis (which includes pulling of chromatids towards centrioles in anaphase) the cell gathers genetic material from the male and female together. Thus, the first mitosis of the union of sperm and oocyte is the actual fusion of their chromosomes.

Each of the two daughter cells resulting from that mitosis have one replica of each chromatid that was replicated in the previous stage. Thus, they are genetically identical.

In other words, the sperm and oocyte don't fuse into one cell, but into two identical cells.

MENSTRUATION

Menstruation is the shedding of the uterine lining - endometrium. It occurs on a regular basis in reproductive-age females of certain mammal species. Overt menstruation (where there is bleeding from the vagina) is found primarily in humans and similar relatives such as chimpanzees. The females of other placental mammal species have estrous cycles, in which the endometrium is reabsorbed by the animal (covert menstruation) at the end of its reproductive cycle. Many zoologists regard this as different from a "true" menstrual cycle.

Overview

Eumenorrhea denotes normal, regular menstruation that lasts for a few days (usually 3 to 5 days, but anywhere from 2 to 7 days is considered normal). The average blood loss during menstruation is 35 millilitres with 10-80 mL considered normal; many women also notice shedding of the endometrium lining that appears as tissue mixed with the blood. (Sometimes this is erroneously thought to indicate an early-term miscarriage of an embryo.)

An enzyme called plasmin — contained in the endometrium — tends to inhibit the blood from clotting. Because of this blood loss, premenopausal women have higher dietary requirements for iron to prevent iron deficiency.

Many women experience uterine cramps, also referred to as dysmenorrhea, during this time, caused largely by the contractions of the uterine muscle as it expels the endometrial blood from the woman's body. A vast industry has grown to provide drugs to aid in these cramps, as well as sanitary products to help manage menses.

Menstruation is the most visible phase of the menstrual cycle. Menstrual cycles are counted from the first day of menstrual bleeding, because the onset of menstruation corresponds closely with the hormonal cycle.

During pregnancy and for some time after childbirth, menstruation is normally suspended; this state is known as amenorrhoea, i.e. absence of the menstrual cycle.

If menstruation has not resumed, fertility is low during lactation.

The average length of postpartum amenorrhoea is longer when certain breastfeeding practices are followed; this may be done intentionally as birth control (lactational amenorrhea method).

Menstrual cycle

The menstrual cycle is a cycle of physiological changes that occurs in pubescent females. Overt menstruation (where there is blood flow from the vagina) occurs primarily in humans and other mammals such as chimpanzees.

Females of other species of placental mammal undergo estrous cycles, in which the endometrium is completely reabsorbed by the animal (covert menstruation) at the end of its reproductive cycle. This article focuses on the human menstrual cycle.

The menstrual cycle, under the control of the endocrine system, is necessary for reproduction. It may be divided into three distinct phases:

• Menstruation,
• The follicular phase and
• The luteal phase.

Ovulation defines the transition from the follicular phase to the luteal phase.

The length of each phase varies from woman to woman and cycle to cycle, though the average menstrual cycle is 28 days.

Hormonal contraception interferes with the normal hormonal changes with the aim of preventing reproduction.

Stimulated by gradually increasing amounts of estrogen in the follicular phase, menses slow then stop, and the lining of the uterus thickens.

Follicles in the ovary begin developing under the influence of a complex interplay of hormones, and after several days one or occasionally two become dominant (non-dominant follicles atrophy and die).

Approximately mid-cycle, 24-36 hours after the Luteinizing Hormone (LH) surges, the dominant follicle releases an ovum, or egg in an event called ovulation.

After ovulation, the egg only lives for 24 hours or less without fertilization while the remains of the dominant follicle in the ovary become a corpus luteum ; this body has a primary function of producing large amounts of progesterone.

Under the influence of progesterone, the endometrium (uterine lining) changes to prepare for potential implantation of an embryo to establish a pregnancy.

If implantation does not occur within approximately two weeks, the corpus luteum will involute, causing sharp drops in levels of both progesterone and estrogen. These hormone drops cause the uterus to shed its lining in a process termed menstruation.

In the menstrual cycle, changes occur in the female reproductive system as well as other systems (which lead to breast tenderness or mood changes, for example). A woman's first menstruation is termed menarche, and occurs typically around age 12. The end of a woman's reproductive phase is called the menopause, which commonly occurs somewhere between the ages of 45 and 55.

Phases

The menstrual cycle is divided into several phases. The average length of each phase is shown below:

Name of phase	Average start day assuming a 28-day cycle	Average end day
Menstrual phase	1	4
Follicular phase (also known as proliferative phase)	5	13
Ovulation (not a phase, but an event dividing phases)	12	16
Luteal phase (also known as secretory phase)	15	26
Ischemic phase (some sources group this with luteal phase)	27	28

Menstruation

Menstruation is also called menstrual bleeding, menses, catamenia or a period. The flow of menses normally serves as a sign that a woman has not become pregnant. (However, this cannot be taken as certainty, as a number of factors can cause bleeding during pregnancy ; some factors are specific to early pregnancy, and some can cause heavy flow.) During the reproductive years, failure to menstruate may provide the first indication to a woman that she may have become pregnant.

Eumenorrhea denotes normal, regular menstruation that lasts for a few days (usually 3 to 5 days, but anywhere from 2 to 7 days is considered normal). The average blood loss during menstruation is 35 milliliters with 10–80 ml considered normal. (Because of this blood loss, women are more susceptible to iron deficiency than are men.) An enzyme called plasmin inhibits clotting in the menstrual fluid. Cramping in the abdomen, back, or upper thighs is common during the first few days of menstruation. When menstruation begins, symptoms of premenstrual syndrome (PMS) such as breast tenderness and irritability generally decrease. Many sanitary products are marketed to women for use during their menstruation.

Follicular phase

This phase is also called the proliferative phase because a hormone causes the lining of the uterus to grow, or proliferate, during this time.

Through the influence of a rise in follicle stimulating hormone (FSH) during the first days of the cycle, a few ovarian follicles are stimulated. These follicles, which were present at birth and have been developing for the better part of a year in a process known as folliculogenesis, compete with each other for dominance. Under the influence of several hormones, all but one of these follicles will stop growing, while one dominant follicle in the ovary will continue to maturity. The follicle that reaches maturity is called a tertiary, or Graafian, follicle, and it forms the ovum.

As they mature, the follicles secrete increasing amounts of estradiol, an estrogen. The estrogens initiate the formation of a new layer ofendometrium in the uterus, histologically identified as the proliferative endometrium. The estrogen also stimulates crypts in the cervix to produce fertile cervical mucus, which may be noticed by women practicing fertility awareness.

Ovulation

When the egg has nearly matured, the level of estradiol in the body has increased enough to trigger a sudden release of luteinizing hormone (LH) from the anterior pituitary gland. In the average cycle this LH surge starts around cycle day 12 and may last 48 hours. The release of LH matures the egg and weakens the wall of the follicle in the ovary, causing the fully developed follicle to release its secondary oocyte. The secondary oocyte promptly matures into an ootid and then becomes a mature ovum. The mature ovum has a diameter of about 0.2 mm.

Which of the two ovaries—left or right—ovulates appears essentially random; no known left/right co-ordination exists. Occasionally, both ovaries will release an egg; if both eggs are fertilized, the result is fraternal twins.

After being released from the ovary, the egg is swept into the fallopian tube by the fimbria, which is a fringe of tissue at the end of each fallopian tube. After about a day, an unfertilized egg will disintegrate or dissolve in the fallopian tube.

Fertilization by a spermatozoon, when it occurs, usually takes place in the ampulla, the widest section of the fallopian tubes. A fertilized egg immediately begins the process of embryogenesis, or development. The developing embryo takes about three days to reach the uterus and another three days to implant into the endometrium. It has usually reached the blastocyst stage at the time of implantation.

In some women, ovulation features a characteristic pain called mittelschmerz (German term meaning middle pain). The sudden change in hormones at the time of ovulation sometimes also causes light mid-cycle blood flow.

Luteal phase

Corpus Luteum

The luteal phase is also called the secretory phase. An important role is played by the corpus luteum, the solid body formed in an ovary after the egg has been released from the ovary into the fallopian tube. This body continues to grow for some time after ovulation and produces significant amounts of hormones, particularly progesterone.^[2] Progesterone plays a vital role in making the endometrium receptive to implantation of the blastocyst and supportive of the early pregnancy; it also has the side effect of raising the woman's basal body temperature.

After ovulation, the pituitary hormones FSH and LH cause the remaining parts of the dominant follicle to transform into the corpus luteum, which produces progesterone and estrogens. The hormones produced by the corpus luteum also suppress production of the FSH and LH that the corpus luteum needs to maintain itself. Consequently, the level of FSH and LH fall quickly over time, and the corpus luteum subsequently atrophies. Falling levels of progesterone trigger menstruation and the beginning of the next cycle. From the time of ovulation until progesterone withdrawal has caused menstruation to begin, the process typically takes about two weeks, with ten to sixteen days considered normal. For an individual woman, the follicular phase often varies in length from cycle to cycle; by contrast, the length of her luteal phase will be fairly consistent from cycle to cycle.

The loss of the corpus luteum can be prevented by fertilization of the egg; the resulting embryo produces human chorionic gonadotropin(hCG), which is very similar to LH and which can preserve the corpus luteum. Because the hormone is unique to the embryo, mostpregnancy tests look for the presence of hCG.

OVULATION

Ovulation is the process in the females menstrual cycle by which a mature ovarian follicle ruptures and discharges an ovum (also known as an oocyte, female gamete, or casually, an egg) that participates in reproduction. Ovulation also occurs in the estrouc cycle of other female mammals, which differs in many fundamental ways from the menstrual cycle.

The process of ovulation is controlled by the hypothalamus of the brain and through the release of hormones secreted in the anterior lobe of the pituitary gland, (Luteinizing hormon (LH) and Follicle Stimulating Hormon (FSH)).

In the follicular (pre-ovulatory) phase of the menstrual cycle, the ovarian follicle will undergo a series of transformations called cumulus expansion, this is stimulated by the secretion of FSH. After this is done, a hole called the stigma will form in the follicle, and the ovum will leave the follicle through this hole.

Ovulation is triggered by a spike in the amount of FSH and LH released from the pituitary gland.

During the luteal (post-ovulatory) phase, the ovum will travel through the fallpoian tubes toward the uterus. If fertilized by a sperm, it may perform implantation there 6–12 days later.

Order of changes in ovary. 1 - Menstruation 2 - Developing follicle 3 - Mature follicle 4 - Ovulation 5 - Corpus luteum 6 - Deterioration of corpus luteum

In humans, the few days near ovulation constitute the fertile phase.

The average time of ovulation is the fourteenth day of an average length (twenty-eight day) menstrual cycle. It is normal for the day of ovulation to vary from the average, with ovulation anywhere between the tenth and nineteenth day being common.

Cycle length alone is not reliable indicator of the day of ovulation. While in general an earlier ovulation will result in a shorter menstrual cycle, and vice versa, the luteal (post-ovulatory) phase of the menstrual cycle may vary by up to a week between women.

Periovulatory phase

For ovulation to be successful, the ovum must be supported by both the corona radiata and cumulus oophorous granulosa cells. The latter undergo a period of proliferation and mucification known as cumulus expansion. Mucification is the secretion of a hyaluronic acid -rich cocktail that disperses and gathers the cumulus cell network in a sticky matrix around the ovum. This network stays with the ovum after ovulation and have been shown to be necessary for fertilization.

An increase in cumulus cell number causes a concomitant increase in antrum fluid volume that can swell the follicle to over 20 mm in diameter. It forms a pronounced bulge at the surface of the ovary called the blister.

Ovulatory phase

Through a signal transduction cascade initiated by LH, proteolytic enzymes are secreted by the follicle that degrade the follicular tissue at the site of the blister, forming a hole called the stigma. The cumulus – oocyte complex (COC) leaves the ruptured follicle and moves out into the peritoneao cavity through the stigma, where it is caught by the fimbriae at the end of the fallopian tube (also called the oviduct). After entering the oviduct, the ovum-cumulus complex is pushed along by cilia, beginning its journey toward the uterus.

By this time, the oocyte has completed meiosis I, yielding two cells: the larger secondary oocyte that contains all of the cytoplasmic material and a smaller, inactive first polar body. Meiosis II follows at once but will be arrested in the metaphase and will so remain until fertilization. The spindle apparatus of the second meiotic division appears at the time of ovulation. If no fertilization occurs, the oocyte will degenerate approximately twenty-four hours after ovulation.

The mucous membrane of the uterus, termed the stratum functionalis, has reached its maximum size, and so have the endometrial glands, although they are still non-secretory.

Postovulatory phase

The follicle proper has met the end of its lifespan. Without the ovum, the follicle folds inward on itself, transforming into the corpus luteum (pl. corpus lutea), a steroidogenic cluster of cells that produces estrogen and progesterone. These hormones induce the endometrial glands to begin production of the proliferative endometrium and later into secretory endometrium, the site of embryonic growth if fertilization occurs. The action of progesterone increases basal body temperature by one-quarter to one-half degree Celsius (one-half to one degree Fahrenheit). The corpus luteum continues this paracrine action for the remainder of the menstrual cycle, maintaining the endometrium, before disintegrating into scar tissue during menses.

Fertility signals

Knowing your own body and being able to tell when you are fertile / ovulating is an important skill and one that every woman should have.
The fact is, there are only certain times in a woman's cycle when she is fertile or ovulating and can get pregnant. So it pays off to know when those times are.

Your body will give you clear clues and signals as to when fertility is approaching and occurring.

A brief note, this system of observing fertility changes has nothing to do with the rhythm method. The rhythm method does not use bodily signals and is often very unreliable due to factors like the ignorance of the natal lunar phase, sickness, stress etc. If you are simply counting days and guessing when you should be fertile, this could be slowing down your bid to conceive.

A woman is fertile when she is ovulating and ovulation usually occurs mid cycle. In fact, ovulation almost always occurs 14 days before the next bleed. Sometimes women do experience a longer or shorter post ovulatory phase (than 14 days) but this usually indicates that there is a hormonal imbalance.

Ovulation occurs 14 days before next bleed this is the rule. And the fertile window can start a few days before that.

See diagram below :

Spontaneous ovulation can also occur during your natal lunar phase.
The table below provides a rough description of the very real physical and emotional symptoms that you can observe throughout your menstrual cycle. It is a brief guide that I have put together from my own observation.

These are some of the signals that you can observe and note down on your Personal Charting System. The time frame is very approximate, so don't worry if your cycle is not the same - everyone is individual.

Week 1 From first day of bleeding	Bleeding and the various symptoms felt during this part of the cycle varies with the individual, ranging from, cramping, back ache, hollow feeling inside vagina or the sensation that your innards will fall out to no ill effects at all. At the post bleeding phase there is generally an increase in physical energy and vitality. The individual is more outgoing and sociable. Sleep patterns and appetite return to normal. Vaginal mucus is dry or absent .
Week 2	As ovulation approaches cervical mucus become wetter, slippery, white (whatever is your individual pattern.)
Ovulation Day 14 approximately	Mucus is very wet and slippery, easily allowing penetration of sperm. Other symptoms may include tender breasts, mood swings, increase in libido, cramps, break through bleeding, desire to be with your partner.
Week 3 After Ovulation moving into pre-menstrual phase	Mucus production slows, becomes drier and thicker . Moods balance out again.
Week 4 Pre-menstrual phase	Pre-menstrual symptoms kick in, which depending upon you, range from bloating, cramps, headaches, mood swings, food cravings, and insomnia. Energy levels decrease, libido may increase. Desire for solitude increases as does intuitive ability.

The table above is not the definitive guide, and each cycle may not be the same, it all depends on how you are and what's going on in your life.

When you observe your body you will start to see a very clear pattern of what happens in your body during your menstrual cycle.

The main fertility indicators to look for are:

• Cervical mucus
• Bodily symptoms - that is moods, aches, libido, appetite, sleep patterns
• Basal Temperature

cervical mucus

MALE REPRODUCTIVE SYSTEM

The human male reproductive system consists of a number of sex organs that are a part of the human reproductive process. In the case of men, these sex organs are located outside a man’s's body, around the pelvic region.

The main male sex organs are the PENIS and the tESTIS which produce semen and sperm, which as part of sexual intercourse fertilize an ovum in a woman's body and the fertilized ovum (zygote) gradually develops into a fetus, which is later born as a child.

PENIS

The penis (plural penises, penes) is an external sexual organ of certain biologically male organisms, in both vertebrates and invertebrates.

The penis is a reproductive organ, technically an intromittent organ, and for placental mammals, additionally serves as the external organ of urination. The penis is generally found on mammals and reptiles.

The penis has a long shaft and enlarged tip called the glans penis. The penis is the male copulatory organ. When the male becomes sexually aroused, the penis becomes erect and ready for sexual intercourse. Erection is achieved because blood sinuses within the erectile tissue of the penis become filled with blood. The arteries of the penis are dilated while the veins are passively compressed so that blood flows into the erectile cartilage under pressure. The male penis is made of two different tissues,and soft spongey tissue. Cartlidge is not in the penis.

Corpus Cavernosum

The corpus cavernosum penis is one of a pair of sponge-like regions of erectile tissuewhich contain most of the blood in the male penis during erection. This is homologousto the corpus cavernosum clitoridis in the female. The term literally means "cave-like body" (plural: corpora cavernosa).

The two corpus cavernosa and corpus spongiosum (also known as the corpus cavernosum urethrae in older texts and in the diagram to the right) are three expandable erectile tissues along the length of the penis which fill with blood during erection. The two corpora cavernosa lie along the penis shaft, from the pubic bones to the head of the penis, where they join. These formations are made of a sponge-like tissue containing irregular blood-filled spaces lined by endothelium and separated by connective tissuesepta. The corpus spongiosum is one smaller region along the bottom of the penis, which contains the urethra and forms the glans penis.

In some circumstances, release of nitric oxide precedes relaxation of muscles in the corpora cavernosa and corpus spongiosum. The spongy tissue fills with blood, from arteries down the length of the penis. A little blood enters the corpus spongiosum; the remainder engorges the corpora cavernosa, which expand to hold 90% of the blood involved in an erection, increasing both in length and in diameter. The function of the corpus spongiosum is to prevent compression of the urethra during erection.

Blood can leave the erectile tissue only through a drainage system of veins around the outside wall of the corpus cavernosum. The expanding spongy tissue presses against a surrounding dense tissue (tunica albuginea) constricting these veins, preventing blood from leaving. The penis becomes rigid as a result. The glans penis, the expanded cap of the corpus spongiosum, remains more malleable during erection because its tunica albuginea is much thinner than elsewhere in the penis.

TESTICLES

The testicle (from Latin testiculus, diminutive of testis, meaning "witness" [of virility], plural testes) is the male generative gland in human. The testes hang outside the abdominal cavity of the male within the scrotum. They begin their development in the abdominal cavity but descend into the scrotal sacs during the last 2 months of fetal development. This is required for the production of sperm because internal body temperatures are too high to produce viable sperm.

Function

Like the ovaries (to which they are homologous), testes are components of both the reproductive system (being gonads) and theendocrine system (being endocrine glands). The respective functions of the testes are:

• producing sperm (spermatozoa)
• producing male sex hormones of which testosterone is the best-known
• Both functions of the testicle, sperm-forming and endocrine, are under control of gonadotropic hormones produced by the anteriorpituitary:
• luteinizing hormone (LH)
• follicle-stimulating hormone (FSH)

EPIDIDYMAE

The epididymis (pronounced /ɛpɨˈdɪdɨmɪs/, plural: epididymides /ɛpɨˌdɪdɨˈmiːdiːz/) is part of the male reproductive system and is present in all male mammals. It is a narrow, tightly-coiled tube connecting the efferent ducts from the rear of each testicle to its vas deferens.

The epididymus is a whitish mass of tightly coiled tubes cupped against the testicles. It acts as a storage place for sperm before they enter the vasa deferentia, tubes that carry sperm form the testes to the urethra.

Role in storage of sperm and exhaggeration

Spermatozoa formed in the testis enter the caput epididymis, progress to the corpus, and finally reach the cauda region, where they are stored. Sperm entering the caput epididymis are incomplete - they lack the ability to swim forward (motility) and to fertilize an egg. During their transit in the epididymis, sperm undergo maturation processes necessary for them to acquire these functions.^[1] Final maturation is completed in the female reproductive tract (capacitation).

During ejaculation, sperm flow from the lower portion of the epididymis (which functions as a storage reservoir). They have not been activated by products from the prostate gland, and they are unable to swim, but are transported via the peristaltic action of muscle layers within the vas deferens, and are mixed with the diluting fluids of the seminal vesicles and other accessory glands prior to ejaculation (forming semen).

The epididymis possesses numerous, long atypical microvilli. These processes are often called stereocillia; this is incorrect, as they neither contain the microtubular structures of cilia nor function like cilia.

1: Epididymis
2: Head of epididymis
3: Lobules of epididymis
4: Body of epididymis
5: Tail of epididymis
6: Duct of epididymis
7: Deferent duct (ductus deferens or vas deferens)

reviewed by Bambang Widjanarko

Last Juni 2009

FEMALE REPRODUCTIVE SYSTEM

The female reproductive system contains two main parts:

1. The uterus, which hosts the developing fetus, produces vaginal and uterine secretions, and passes the male's sperm through to the fallopian tubes; and
2. The ovaries, which produce the female's egg cells.

The vagina meets the external organs at the vulva, which includes the labia, clitoris and urethrae. The vagina is attached to the uterus through the cervix, while the uterus is attached to the ovaries via the Fallopian tubes.

At certain intervals, the ovaries release an ovum, which passes through the Fallopian tube into the uterus. If, in this transit, it meets with sperm, the sperm penetrate and merge with the egg, fertilizing it. The fertilization usually occurs in the oviduct, but can happen in the uterus itself. The zygote then implants itself in the wall of the uterus, where it begins the processes of embryogenesis and morphogenesis. When developed enough to survive outside the uterus, the cervix dilates and contractions of the uterus propel the fetus through the birth canal, which is the vagina.

The ova are larger than sperm and are generally all created by birth. Approximately every month, a process of oogenesis matures one ovum to be sent down the Fallopian tube attached to its ovary in anticipation of fertilization. If not fertilized, this egg is flushed out of the system through menstruation.

THE FEMALE EXTERNAL GENITAL ORGAN

THE FEMALE INTERNAL GENITAL ORGAN

	1: fallopian tube, 2: bladder, 3: pubic bone, 4: g-spot, 5: clitoris, 6: urethra, 7: vagina, 8: ovary, 9:sigmoid colon, 10: uterus, 11: fornix, 12: cervix, 13:rectum, 14: anus

VAGINA :

The vagina is a fibromuscular tubular tract leading from the uterus to the exterior of the body in female .
The vagina is the place where semen semen from the male is deposited into the female's body at the climax of sexual intercourse, commonly known as ejaculation. Around the vagina, pubic hair protects the vagina from infection and is a sign of puberty.

CERVIX :

The cervix (or neck of the uterus) is the lower, narrow portion of the uterus where it joins with the top end of the vagina. It is cylindrical or conical in shape and protrudes through the upper anterior vaginal wall. Approximately half its length is visible with appropriate medical equipment; the remainder lies above the vagina beyond view. It is occasionally called "cervix uteri". Cervix means neck in Latin.

Anatomi cervix :

Ectocervix

The portion projecting into the vagina is referred to as the portio vaginalis or ectocervix. On average, the ectocervix is 3 cm long and 2.5 cm wide. It has a convex, elliptical surface and is divided into anterior and posterior lips.

External os

The ectocervix's opening is called the external os. The size and shape of the external os and the ectocervix varies widely with age, hormonal state, and whether the woman has had a vaginal birth. In women who have not had a vaginal birth the external os appears as a small, circular opening. In women who have had a vaginal birth, the ectocervix appears bulkier and the external os appears wider, more slit-like and gaping.

Endocervical canal

The passageway between the external os and the uterine cavity is referred to as the endocervical canal. It varies widely in length and width, along with the cervix overall. Flattened anterior to posterior, the endocervical canal measures 7 to 8 mm at its widest in reproductive-aged women.

Internal os

The endocervical canal terminates at the internal os which is the opening of the cervix inside the uterine cavity.

Cervical crypts

There are pockets in the lining of the cervix known as cervical crypts. They function to produce cervical fluid.

UTERUS :

The uterus (Latin word for womb) is a major female hormone-responsive reproductive sex organ of most mammals, including humans. It is within the uterus that the fetus develops during gestation. The term uterus is used consistently within the medical and related professions; the Germanic term,womb is more common in everyday usage. The plural of uterus is uteruses or uteri.

One end, the cervix, opens into the vagina; the other is connected on both sides to the Fallopian tubes.

FALLOPIAN TUBE :

The Fallopian tubes, named after Gabriel Fallopius (Gabriele Fallopio), also known as oviducts, uterine tubes, and salpinges (singular salpinx) are two very fine tubes lined with ciliated epithelia, leading from the ovaries of female mammals into theuterus.

There are two Fallopian tubes attached to either side of the cornual end of the uterus at the axilla of Welch. Each terminates at or near one ovary forming a structure called the fimbria.

The Fallopian tubes are not directly attached to the ovaries, but open into the peritoneal cavity (essentially the inside of the abdomen); they thus form a direct communication between the peritoneal cavity and the outside via the vagina. In human, the Fallopian tubes are about 7–14 cm long.

If a Fallopian Tube is missing from the pair, then the other fallopian tube that is functional could still be a way of carrying an egg down to the uterus.

Regions

There are four regions of the fallopian tube from the ovary to the uterus:^[1]

• Infundibulum - contains fimbria
• Ampulla - usual site of fertilization
• Isthmus
• Intramural oviduct - inside wall of uterus

OVARIES

The ovary is an ovum-producing reproductive organ, often found in pairs as part of the female reproductive system. Ovaries in females are homologous to testes in males, in that they are both gonads and endocrine glands.

Ovaries are oval shaped and, in the human, measure approximately 3 cm x 1.5 cm x 1.5 cm (about the size of a Greek olive). The ovary (for a given side) is located in the lateral wall of the pelvis in a region called the ovarian fossa. The fossa usually lies beneath the external iliac artery and in front of the ureter and the internal iliac artery.

Each ovary is then attached to the fimbria of the fallopian Tube. Usually each ovary takes turns releasing eggs every month; however, if there was a case where one ovary was absent or dysfunctional then the other ovary would continue providing eggs to be released.

Hormones

Ovaries secrete both Estrogen and Progesterone. Estrogen is responsible for the appearance of secondary sex characteristics of females at puberty and for the maturation and maintenance of the reproductive organs in their mature functional state. Progesteronefunctions with Estrogen by promoting cyclic changes in the endometrium (it prepares the endometrium for pregnancy), as well as by helping maintain the endometrium in a healthy state during pregnancy.

Reviewed by Bambang Widjanarko, Obstetrician & Gynecologist

Last Juni 2009