Role of hormones during pregnancy

A woman's first pregnancy is one of the most exciting and dramatic events of her life. As conception progresses to implantation, and an embryo eventually becomes the fetus that ultimately will be the highly anticipated bundle of joy, numerous changes take place within the woman's body to enable this miraculous process to occur. While a woman's physical changes may be obvious, several other ones may be subtle, including a growing sense of immense emotional attachment and reprioritization. The vast majority of these changes are attributable to the hormones of pregnancy.

The first trimester of pregnancy begins with conception. As egg and sperm unite, and the conceptus implants into the endometrium or uterine lining, a hormone called human chorionic gonadotropin (HCG) is produced. HCG has a very predictable rise in the early weeks of pregnancy and peaks around 70 days. HCG is thought to support the pregnancy by ensuring ovarian production of progesterone until the placenta is well formed around the tenth week. HCG is thought to be the hormone responsible for a number of symptoms associated with early pregnancy, namely nausea and resultant vomiting and the sometimes overwhelming fatigue that can plague the very early expectant woman. Progesterone is one of the major hormones of pregnancy and is primarily produced by the placenta. Levels of progesterone in the body rise as pregnancy progresses. Progesterone functions to inhibit the smooth muscle in the uterus from contracting and decreases prostaglandin formation, both of which allow the fetus to grow with the expanding uterus. As progesterone levels increase, other smooth muscle in the body may also be affected, such as that in the lower esophageal sphincter, which results in increased heartburn and acid reflux, especially in the later stages of pregnancy. Progesterone softens cartilage as well and may be responsible for the commonly occurring hip and pubic bone pain that also occurs. This hormone also can cause tenderness in the breasts read more