Problems with ovulation account for most infertility in women. Without ovulation, eggs are not available to be fertilised. Signs of problems with ovulation include irregular menstrual periods or no periods. Simple lifestyle factors – including stress, diet, or athletic training – can affect a woman’s hormonal balance. Much less often, a hormonal imbalance from a serious medical problem such as a pituitary gland tumour, can cause ovulation problems.

Aging is an important factor in female fertility. The ability of a woman’s ovaries to produce eggs declines with age, especially after age 35. About one third of couples where the woman is over 35 will have problems with fertility. By the time she reaches menopause, when her monthly periods cease, a woman can no longer produce eggs or become pregnant.

There are also other problems that can lead to infertility in women. If the fallopian tubes are blocked at one or both ends, the egg can’t travel through the tubes into the uterus. Blocked tubes may result from pelvic inflammatory disease, endometriosis, or surgery for an ectopic pregnancy.