Late motherhood is a growing trend in the United States with 8 times as many women giving birth to their first child beyond the age of 35 as compared to four decades ago.
The most important predictor of fertility is female age. As women age, egg counts and egg quality, defined as the egg’s ability to create a chromosomally normal embryo, both decline. This results in higher rates of infertility, miscarriage and childlessness.
Women are born with a set number of eggs. Every month, eggs are lost through ovulation and natural egg death. By age 30, women lose 88% of their life supply of eggs and by age 40, egg loss reaches 97%. The chance of a live birth from natural conception on a monthly basis declines from 20% at age 30 to 15% at age 35, 10% at age 40 and only 1-2% at age 45.
Based on the above, women should consider having children earlier in life in order to prevent infertility and childlessness. Those who are not ready to have children should consider a fertility check-up to estimate the number of remaining eggs and identify health factors that could impact later efforts to conceive. Women may also wish to consider fertility preservation by freezing eggs or embryos while they are still reproductively young.
A variety of fertility treatments are available for women in their late 30’s and early 40’s who are having difficulty conceiving. In general, fertility treatments increase the chance of pregnancy by stimulating the ovary to grow multiple eggs as opposed to the one egg that typically grows each month. Multiple egg recruitment can be achieved by taking a fertility pill called clomiphene citrate or by daily injections of the hormone FSH.