These changes are brought about by female hormones, each of which plays a specific role. The levels of hormones change during pregnancy, and each hormone has a specific function. Certain hormones after pregnancy eventually decrease in secretion till they are brought down to a normal level or eliminated.
Effects of Hormones in Pregnancy
Beta Human Chorionic Gonadotropin Hormone (b-HCG )
This is one of the main hormones found in pregnant women. It is tested for in home pregnancy tests. Its production begins approximately a week after impregnation. As implantation occurs, the secretion of b-HCG starts. It encourages the corpus luteum (which is commonly called 'yellow body') to produce estrogen and progesterone, and other vital hormones.
This is till the formation of the placenta, which then takes over this function. Once this occurs, the levels of b-HCG drops dramatically in the second trimester. Also, b-HCG is responsible for stimulation of the gonad development in the fetus.
Luteinizing Hormone (LH)
Luteinizing hormone is present in both males and females. It is released from the pituitary gland, and its secretion is initiated by the surge in levels of estrogen, by the positive feedback effect. However, in females, it is one of the main hormones that triggers off the ovulation process, that is release of the egg from the ovary.
It also converts the residual follicle into corpus luteum, which produces progesterone. LH hormone maintains the functioning of the corpus luteum for the first two weeks, ensuring smooth and continuous production of estrogen and progesterone. Its action is regulated by the b-HCG.
Follicle-stimulating Hormone (FSH)
This hormone acts synergistically with luteinizing hormone, and is one of the main hormones during early pregnancy. This is initially secreted, and it helps in maturing the follicle to produce the egg. Also, the residual follicle maturation to corpus luteum is assisted by this hormone.
Progesterone is secreted by the corpus luteum. It is the main hormone during pregnancy that readies the uterus for implantation. It increases the blood supply of the endometrium (uterine wall). It stimulates the glands present in the endometrial wall to secrete uterine fluid, which nourishes the embryo.
As long as progesterone levels are high, menstruation does not occur, and hence it is this hormone during pregnancy that prevents menstruation, and prevents any further eggs from being released. It also maintains the functioning of the placenta, and protects the fetus.
This hormone stimulates the growth of the mammary gland, while preventing lactation until birth. It also makes the pelvic wall stronger for labor and prevents the uterus from contracting until the baby is fully developed. Progesterone shows a dramatic drop in its level after pregnancy.
Estrogen is the hormone secreted by the corpus luteum, until the placenta takes over. It creates the glands that are present in the endometrium, which secretes the uterine fluid. Its levels increase steadily until birth. Estrogen also regulates the secretion of progesterone, along with other hormones.
Estrogen plays an important role in development of the fetus, with various organs and systems in the fetus being triggered into development by estrogen. It also regulates the bone density in the fetus. It is the reason behind the 'glow' which is seen in pregnancy.
Other pregnancy hormones include human placental lactogen, relaxin, erythropoietin, cortisol, oxytocin, and prolactin. Oxytocin is the hormone that contracts the uterus during childbirth, and stretches the cervix. It also stimulates the nipples.
Lactogen is one of the acting hormones after pregnancy, as it is involved in the production of milk. Even progesterone is one of the main hormones after pregnancy. Calcitonin is a hormone that prevents decalcification of the bones.
This was an overview of the commonly found hormones in pregnant women.
Disclaimer: This is for informative purposes only and does not in any way attempt to replace the advice offered by an expert on the subject.