Having Sex
There’s a popular question of if it is safe to have sex during pregnancy. Yes, it is as long as your water hasn’t broken. It is also often recommended for getting labor started.
It may be effective for a few reasons, including the fact that semen is high in prostaglandins. This is a hormone that can cause contractions in uterine muscles.
So, for sex to help haste you into labor, your partner should ejaculate inside your vagina.
Having an orgasm can also stimulate the uterus, and sex in general can release the hormone oxytocin, [1] which causes contractions. For people who begin nursing after a baby is born, this same hormone is responsible for shrinking the uterus to its pre-pregnancy size.