By Lynne Peeples
NEW YORK | Wed Jul 7, 2010 2:15pm EDT
Events surrounding a baby girl’s birth may affect the age at which she later goes through menopause.
In a study of more than 20,000 middle-aged Puerto Rican and American women, researchers found that exposure in the womb to the man-made estrogen, diethylstilbestrol (DES), as well as certain characteristics of the mom, had small effects on the timing of this natural biological process.
“These aren’t drastic changes, but the fact that something at birth can affect something 50 years later is fascinating,” Dr. Anne Steiner of the University of North Carolina at Chapel Hill told Reuters Health.
A woman’s ovaries hold the most eggs while she is in her mother’s womb: about 5 million at 24 weeks gestation. By birth, she’s left with roughly 2 million. The count continues to fall until menopause, when the last 1,000 eggs of her supply begin to run out and menstruation and fertility end.
This knowledge led Steiner and her colleagues to wonder if the womb might be a susceptible time period for women. Could things about her mom, the environment or the birth itself affect how many eggs a girl has when she’s born? And might this subsequently alter her age at menopause?