Pregnancy and smoking: How is fertility affected if you have a girl?

Experiments on mice showed that oxygen deprivation, also known as hypoxia, led to the birth of female mice with fewer ovaries.
The women have been warned of its dangers smoking during pregnancy for years, with the fetus at risk of heart problems and other health issues. However, at least 1 in 10 women smoke while pregnant. Scientists from the University of Cambridge have discovered that it also causes other problems, such as the child's fertility in the following decades.

Their findings are the first to show that girls born to pregnant women who smoke may have difficulty having children of their own. Experiments on mice showed that oxygen deprivation, also known as hypoxia, led to the birth of female mice with fewer ovaries. The researchers said mice are a useful model for studying human pregnancy because their reproductive biology shares many commonalities.

They believe that the same thing happens to girls, resulting in reduced fertility and early menopause. The scientists exposed the mice to reduced levels of oxygen (13% instead of the standard 21%) from days six to twenty of their pregnancy. They then looked at the reproductive extent of the female children and found 30% a reduction in the number of ovarian glands. Women are born with a certain number of glands with each having a chance to develop into an egg. In humans, women lose their eggs around 50, which is when menopause begins.

Dr. Kathryn Aiken, from the department of gynecology at the University of Cambridge, said: 'It's as if low oxygen levels cause ovarian tissue to age more quickly. Biologically, the tissue appears larger and the eggs decline at a younger age than normal.