Hormones During the First Trimester of Pregnancy

Human Placental Lactogen (hPL)

Human placental lactogen is a growth hormone made by the placenta. It affects your metabolism by breaking down fat to provide nutrition for your developing baby.

Human Gonadotropic Hormone (hCG)

Except in the case of very rare ovarian tumors, hCG is produced only during pregnancy. Doctors can tell how well a pregnancy is progressing by measuring the increase in the amount of hCG. In a healthy pregnancy, hCG values double every two days or so in the early part of the first trimester.

The level of hCG plateaus near the end of the first trimester, leading doctors to believe it may have something to do with morning sickness (which usually lessens at this time). The most apparent biological effect of hCG is to regulate progesterone production from the site on your ovary where you ovulated, that part of the ovary remaining as something called the corpus luteum. This progesterone regulation plays a role in sexual differentiation of your baby.

Prolactin

Prolactin, the hormone that stimulates milk production, acts when the estrogen and progesterone decrease at the end of pregnancy. Thyroid hormones and insulin work together to pull this off, but prolactin is the main regulator for the onset and regulation of lactation.

While there isn't much you can do to lessen the symptoms of surging hormones, understanding their role in your pregnancy just might help you tolerate the ride!