Is there a mechanism in the body that stops this, or is it that the sperm can’t get to an egg anymore?
In: 33
Several things.
A woman’s menstrual cycle stops while she’s pregnant. Since her cycle is paused, the follicles in her ovaries do not mature, and thus she does not normally produce any eggs during pregnancy. (People will sometimes loosely say that women are born with all of their eggs, but more properly they’re born with all of their ovarian follicles, and those mature into eggs later.)
And in case that weren’t enough, there’s a thick layer of mucus called the *cervical plug* at the bottom of the uterus during pregnancy. That plug seals off the interior of the uterus from the outside world, protecting the embryo/fetus from e.g. infection. This mucus is present normally, but it’s thickened enough during pregnancy that sperm can’t swim through it. (In fact, artificially thickening it is part of how some birth control works.)
Latest Answers