Do women make new eggs every cycle?
While males set up an in-body manufacturing operation to meet ongoing demand for sperm, females employ a different egg-readiness strategy. They pack all the eggs they’re going to need for their entire reproductive journey before they’re even born.
A female baby’s ovaries contain approximately one million ova at birth, explains Bruce Young, M.D., founder of the division of maternal and fetal medicine at NYU Medical Center; and author of Miscarriage, Medicine, & Miracles: Everything You Need to Know about Miscarriage (Bantam, 2008). By puberty, when a girl starts menstruating, the number of eggs remaining is down to 300,000 to 400.000.
That’s when things start to get exciting from a biological standpoint. During each menstrual cycle, a number of eggs begin to ripen. Your body chooses one (sometimes more than one) as the ovulatory front runner. Mother Nature has factored a lot of excess capacity into the system. An average women releases 400 eggs through ovulation during her lifetime, only a tiny fraction of a percent of the eggs she was born with. And obviously
only a tiny percentage of the released eggs will ever be fertilized to grow into a baby.
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