Polycystic Ovarian Disease or PolyCystic Ovarian Syndrome is a set of symptoms that is the most common female endocrine disorder affecting most of the women of reproductive age (12-50 years). It is a disorder with many different faces, and it causes great emotional and physical distress to the millions of women worldwide who suffer from it. It is one of the leading causes of female infertility. It usually occurs when the female hormones are imbalanced and certain male hormones are produced causing various signs and symptoms. Some women may have a mild presentation of symptoms while in others a severe disturbance of reproductive, endocrine, and metabolic functions.
There are many signs and symptoms of PCOS, but among all those 3 of them are the main ones for the diagnosis
- oligo /amenorrhoea (scanty or no menstrual periods for more than 3 consecutive months)
- hyperandrogenism (increased androgen hormone in the blood)
- cysts on ovaries (visualized with the help of an ultrasound scan)
Along with these are the symptoms of irregular periods sometimes associated with heavy bleeding, abnormal weight gain or obesity, facial hair growth or hair loss, darkening or thickening of the skin, insomnia, fatigue, acne.
The real cause of PCOD still remains unknown. However, the following are found to have a role in causing the condition
- Genes – if a family member has PCOS, there are 50% chances of you developing it.
- Androgens – increased androgens and testosterone (male hormones) in the body prevents ovaries from performing their functions normally
- Insulin resistance – when cells can’t use the insulin properly, the pancreas produces more insulin which again increases the production of male hormones.
- Hypothyroidism – Changes in thyroid function can also influence levels of sex hormone-binding globulin (SHBG). This compound serves to bind up the male hormones in the blood, and when levels are low, male hormones run rampant in the body, producing all of the unpleasant symptoms of PCOS.
PCOS is a common female endocrine disorder. So, what happens in PCOS? Before understanding the cause for PCOS, let’s understand the physiology of the normal menstrual cycle.
The menstrual cycle is the regular monthly period that every girl gets, who has attained menarche or puberty. The cycle begins from the first day of the period and usually, the length of a cycle usually ranges from 21-35 days. There are, in each cycle, phases during which certain changes occur which are controlled by hormones released from the pituitary and hypothalamus situated in the brain along with ovaries.
The phases are follicular phase, ovulatory phase, and luteal phase. The following table explains in brief the events occurring in a 28-day cycle.
This phase begins with the first day of the period and ends with the ovulation on the 14th day. Bleeding usually lasts for 5 days, with the first 2 days of heavy bleeding. Along with the bleeding, simultaneously, the ovaries prepare for the next ovulation. The pituitary gland secretes FSH-follicle stimulating hormone, which causes follicles to develop in ovaries. Among many follicles which develop, only one of them will become dominant and within which a mature egg is formed. The maturing follicle produces the hormone oestrogen, which increases over the follicular phase and peaks in a day or two prior to ovulation. The lining of the uterus called the endometrium increases in thickness and blood supply also increases in response to the increased oestrogen levels. The increase in oestrogen levels stimulates the release of GnRH-gonadotropin-releasing hormone, which in turn stimulates the release of LH- luteinizing hormone from the pituitary. On about the 12th day there will be a surge in LH and FSH hormones which causes the release of an egg from the follicle.
This phase is the one where the egg or ovum is released from the follicle (ovary). It occurs on the 14th day of the cycle due to the LH and FSH surge. The egg then reaches the fallopian tube. If sperms are present, the egg is fertilized and tries to implant on the lining of the uterus, endometrium. If the egg is not fertilized, then it degenerates within 24 hours and is expelled from the body during the next menstrual cycle.
After the egg is released, FSH and LH decreases and the follicle forms into the corpus luteum, which produces the hormone progesterone. If fertilization takes place, corpus luteum continues to produce progesterone which prevents the endometrium from being shed. In the absence of fertilization, the corpus luteum disintegrates and causes progesterone levels to drop, thereby causing the endometrium to shed. Thus the menstrual bleeding begins marking the end of the previous cycle and beginning of the next cycle.
This is the normal changes that happen during a menstrual cycle. Now, what happens in PCOS? In PCOS, the LH hormone remains high when the menstrual cycle starts, higher than FSH level. As LH is high, no LH and FSH surge occurs, hence no ovulation and no progesterone, so periods are absent or irregular. As the follicles do not rupture, they remain on the ovary and appear like “cysts” in an ultrasound study. Hence, it’s called poly (=many) cystic ovaries.
The other causes of PCOS are insulin resistance. Insulin is required for regulating sugar levels in the body. When there is insulin resistance, the body produces more insulin to maintain blood sugar levels. The extra insulin causes an imbalance of the hormones responsible for the normal menstrual cycle.
High amounts of LH and FSH produce more male hormones testosterone. Hypersecretion of LH by pituitary- a result of both disordered ovarian- pituitary feedback and exaggerated pulses of GnRH from the hypothalamus- stimulates testosterone secretion by the ovary. Furthermore, insulin is a potent stimulus for androgen secretion by the ovary which, by the way of a different receptor for insulin, does not exhibit insulin resistance. Thus high levels of male hormones prevent ovulation along with other related symptoms. When the ovulation does not occur, multiple ‘cysts’ -which are actually immature follicles- are formed on the ovaries.