Monthly events in uterus and ovaries (controlled by hormones) throughout reproductive phase of women is called as menstrual cycle. On an average duration of menstrual cycle is 28 (+7) days.
Menstruation is the result of the endometrial layer (the inner layer of the uterus) coming out of uterus due to non-fertilization & non-implantation of ovum.
During menstruation, there is a 50–180 ml of menstrual discharge. It is also called as monthly vaginal bleeding/ menstruation/ menses/ periods (4 – 5 days). It is a normal biological process and it is not a disease.
Thick superficial layer of uterine endometrium gets detached and passes through vagina.
Follicular phase begins on first day of menstrual bleeding. Main event in this phase is development of follicles in the ovaries. Follicle-stimulating hormone (FSH) stimulates the growth of 3-30 follicles. Each follicle contains an egg. Later, only one of these follicles (called the dominant follicle) continues to grow.
This phase begins when the level of Luteinising hormone levels increase LH stimulates the dominant follicle to bulge from the surface of ovary and finally rupture, releasing the egg. The ovulatory phase usually lasts 16 to 32 hours. Fertilization is most likely when sperm are present in the reproductive tract before the egg is released.
This Phase begins after ovulation and lasts about 14 days (unless fertilization occurs) and ends after a menstrual period.
Progesterone causes endometrium to thicken.
If the egg is not fertilized, corpus luteum degenerates after 14 days and a new menstrual cycle begins. But, if the egg is fertilized; the cells around the developing embryo begin to produce called human chorionic gonadotropin (HCG). HCG maintains the corpus luteum, which produce progesterone, until the growing fetus can produce its own hormones. Pregnancy tests are based on detecting an increase in the HCG level.
The four major hormones in relation to Menstrual cycle
Menstrual Cycle is regulated by the complex interaction of hormones
|1. Follicle stimulating hormone (FSH)||Stimulates formation of ova in follicles of ovary.||FSH & LH are gonadotropins, secreted by pituitary gland in brain|
|2. Leutinizing hormone (LH)||Release ova from ovary by breaking ovarian follicles|
|3. Estrogen (Secreted by follicles)||Prepares Endometrium in uterus every month||Estrogen & Progesterone are female sex hormones secreted from ovaries|
|4. Progesterone (Secreted by Corpus Luteum of ovary)||Maintains integrity of endometrium inside uterus during pregnancy|
Fertilization (also known as conception, fecundation and syngamy) is the fusion of gametes to produce a new organism. In humans, the process involves the fusion of an ovum with a sperm which eventually leads to the development of an embryo.
Implantation (human embryo), an event that occurs early in human pregnancy in which the human embryo adheres to the wall of the uterus.
Gastrulation, which occurs around 16 days after fertilization, when the single-layered blastula reorganizes into three layered structure called gastrula. This has presence of three germ layers, the endoderm, the ectoderm and the mesoderm
Infertility is defined as the biological inability of a person to contribute in fertilization or conception.
Inability to achieve pregnancy after one year of unprotected intercourse if the female is below age 30 and 6 months if the female is above 30 years (American Society of reproductive medicine)
Causes Of Infertility In Men
1.Defects in Sperms:
- Oligospermia – few spermatozoa in semen
- Hypospermia – small semen volume
- Aspermia – complete lack of semen
- Azoospermia – absence of sperm cells in semen
- Teratospermia – sperm with abnormal morphology
- Asthenozoospermia- reduced sperm motility
2.Varicocele: Is an abnormal enlargement of the vein that is in the scrotum draining the testicles.
3.Movement of the sperm: This may be caused by the shape of the sperm.
Sometimes Injuries or other damage to the reproductive system block the sperm.
4.Birth Related: Sometimes a man is born with the problems that affect his sperm.
5.Illness /Injury: Other times problems start later in life due to Illness or Injury. For example, cystic fibrosis often causes Infertility In men.
6.Life style Problem: A man’s sperm can be changed by his overall health and lifestyle. Some things that may reduce the health or number of sperm Include:
- Heavy alcohol use , drugs
- Environmental toxins, including pesticides and lead
- Smoking Cigarettes
Health problems such as mumps, serious conditions like kidney disease, or hormone problems Medicines radiation treatment and chemotherapy for cancer
Causes of Infertility in Women.
1.Polycystic ovarian syndrome (PCOS): Is the most common cause of infertility.
PCOS is related to imbalance of female sex hormones. Too much androgen are made, the eggs in the follicles do not mature and doesn’t ovulate. Instead form a small cyst in the ovary rise in the level of LH hormones.
2.Primary ovarian insufficiency (POI): POI occurs when a woman’s ovaries stop working normally before she is 40.
3.Blocked Fallopian tubes: It is due to pelvic inflammatory disease, endometriosis, or surgery for an ectopic pregnancy.
4.Problems with ovulation: Without ovulation, there are no eggs to be fertilized.
5.Physical problems with the uterus
6.Uterine fibroids: non-cancerous lumps of tissue and muscle on the walls of the uterus.
7.The other factors include:
- Poor diet
- Athletic training
- Being overweight or underweight
- Excess alcohol use
- Sexually transmitted infections (STIs)