An ovulation or absence of egg production is one of the commonest causes of not being able to get pregnant. PCOS or polycystic ovarian disease is the most important reason for an ovulation and affects almost 1 in 6 women. Women with polycystic ovarian disease tend to have irregular periods and hormone imbalance which may also produce facial hair growth, oily skin, weight gain and pimples. 

Figure: Egg release, fertlilization and transport of embryo through tube.

Eggs normally grow within fluid filled sacs called follicles. The aim of ovulation induction is to produce the growth of a minimum of one follicle and not more than 3 follicles. For this to occur, we use tablets (clomiphene citrate) , hormone injections (gonadotrophins) or both together.

A scan is performed before starting treatment on day 2 of the period. Serial scans are done to assess the growth of the follicles and when they reach 18mm – 20mm, an injection called HCG is given for the egg to be released from the follicle (ovulation). At this time, intercourse is advised . If IUI (intrauterine insemination) has been planned, then it is done at the time when the egg is released.