For both men and women, waiting too long may have negative consequences when they do try to get – or get their partner – pregnant.
Even with advances in medicine, approximately 50% of women are running out of time – as their biological clock stops at age 41.
Just What is the Biological Clock?
The phrase ‘biological clock’ was originally coined by scientists to describe how our bodies regulate circadian rhythms – when we eat, sleep and wake up.
Nowadays, however, those words conjure fear and stress in women over 30, as they consider the end of their body’s natural state of fertility.
When Does the Biological Clock Start Ticking?
Every woman's ‘clock' starts ticking when she is still a fetus inside the womb. A female has six to seven million eggs – the highest number she will ever have – at 20 weeks gestation, in utero.
From there, the number of eggs begins to diminish. By the time a female infant is born, she has approximately 1-2 million eggs left.
Technically, the “real ticking of the biological clock” starts at this point, as this is the true beginning of a woman's reproductive years. At this point, there are approximately 300,000 – 500,000 eggs left. A woman is most fertile when she is in her early to mid-20s.
Fertility declines gradually after that but begins to decline rapidly after 35. The drop is most dramatic after the age of 37.