Why We Sleep

Pregnancy, especially early pregnancy, makes ladies very very tired. And the main reason for this might be the hormone progesterone, which has a sleep-inducing effect.

Progesterone production increases ten-fold during pregnancy and is produced by the ovaries for the first seven weeks after which the placenta takes over production.

Another reason for the need to nap after brekkie, as I'm doing in the photo to your left, is because a woman's metabolic rate falls early in pregnancy. Why this happens is unknown, like most of pregnancy and labor.

My own theory to go along with the hormone and metabolic ideas is that we're just getting used to doing all the work of building another human being. Eventually, like all endurance sports, we get used to it and adapt.