I was just asked if there was a scientific explanation for the loss or decrease of sex drive or libido that some women experience after childbirth if women are breast-feeding?
I think most moms would say, "Hello! We're tired." I think sleep deprivation for all parents is the # 1 factor for their completely normal decline in canoodling.
There are other factors at play here when women breastfeed. The hormone prolactin that makes milk, inhibits the release of estrogen (our #1 hormone for sexiness and libido.) Remember that there are more estrogen receptors in the vulva (private girl parts, this is my scientific term) than any other place in the body.
Women who breastfeed may notice that their private girl parts don't look the same as they did in the past. The labia shrinks and things are a little less moist. Some would say Desert Dry. This isn't from a vaginal birth, because it happens for women who had a C-Section.
What happens is that mother nature doesn't want women to be hot for their partners too soon after giving birth. In order for that baby to have enough milk to survive, it's essential that a mom NOT ENJOY SEX and make another baby, which would decrease milk supply.
In a nutshell
Prolactin inhibits Estrogen which decreases libido, makes areas Sahara dry, changes arousal patterns and frankly prolongs the time it takes to have an orgasm. Many breastfeeding moms find that having an orgasm takes Forever and they give up and get some sleep. (unless the breast stimulation overrides that, which is another story).
Choices
If you like to bet, when new parents are in the Casino of Love, and given the choice between Sex & Sleep, they choose Sleep more often than Sex. Read more on
Sex Versus Sleep