A woman's reproductive system is complex

The female reproductive system is composed of  the ovaries (which produce eggs), the cervix and the uterus as well as a complex hormonal system. The ovaries and the pituitary gland of the brain produce sex hormones to prepare the body to support a pregnancy.

Women are born with all their eggs and are unable to produce more

Unlike men, who produce new sperm throughout most of their lifetime, women are born with all their eggs (about 1 million immature oocytes). At  puberty, only about 300,000 remain, and of these, 300 to 400 will be ovulated.

The egg lives about 24 hours after ovulation

During each menstrual cycle, a mature egg (ovum) is released into the fallopian tube. This marks the start of ovulation (around day 14 of a regular 28-day menstrual cycle). The egg lives about 24 hours after ovulation, and it is within this time frame that conception can take place.

Most women get pregnant within 3 years of having regular unprotected sex

Among women who are aged 35, 95% will get pregnant within three years of having regular unprotected sex. For women who are 38, 75% will get pregnant within three years.

Conception normally occurs in the fallopian tubes

If the egg is fertilised, it will attach to the womb lining after about 5 days . If no conception occurs, the womb lining will detach, leading to menstruation

It takes about 4 months, prior to ovulation, for the egg to mature

For most of her life, a woman's eggs are in an immature state. In the four months prior to ovulation, the egg matures and goes through a major transformation. It is during this stage when many factors can affect the development of the egg, either positively or negatively