Pregnancy is a fantastic time in a woman’s life. Her body becomes a nurturing home for a precious life, providing everything needed until the baby is ready to make their entrance into the world. To watch the growth of a pregnancy occur is quite amazing and can be seemingly simple. However, the start, progression, and ending of a pregnancy all involve a special and specific interaction of a variety of hormones that flood a woman’s body from even before the time the sperm meets the egg. Parents Magazine identifies six major hormones that play a major role in pregnancy.

Human Chorionic Gonadotropin (hCG)

Human Chorionic Gonadotropin is a hormone many women first come to know when using an at-home pregnancy test. These tests measure the level of this hormone in the urine, and if high enough, indicate to the women that pregnancy has been achieved. This hormone is made by cells in what eventually form the placenta. The level of hCG in the body double about every two days, reaches its highest level around 60 to 90 days, then decreases to a stable level for remaining of the pregnancy. One job of this hormone is to sends signals to the ovaries to stop producing eggs. Its main role is to allow the corpus luteum, which is a cyst on the ovary, to continue to make estrogen and progesterone until the placenta is mature enough to handle to the production of these hormones. The level of hCG begins to decrease once the placenta takes over the production of estrogen and progesterone.


No other hormone is more associated with women than estrogen. Responsible for critical fetal development, estrogen allows for the organs and body systems in the fetus to develop. Estrogen also triggers the growth of the adrenal gland of the fetus and the hormones that it produces. Additionally, it allows the uterus to be responsive to oxytocin. Pregnant women can experience nausea, spider veins, changes in skin, and an increased appetite due to high levels of estrogen in the body.


Encyclopedia Britannica explains that progesterone plays a critical factor in a woman becoming pregnant as it allows the uterine wall, or endometrium, to thicken which allows for implantation of a fertilized egg. During pregnancy, the hormone relaxes all the smooth muscles in the body which includes the wall of the uterus. Blood vessels in the body also become relaxed which contributes to the dizziness, lower blood pressure, and some gastrointestinal issues that pregnancy can bring such as gas, heartburn, nausea, and constipation. Progesterone is also responsible for the rise in hair growth on the body during pregnancy.


Oxytocin is the hormone associated with labor. The uterus becomes sensitive to the hormone as the pregnancy prepares to end. It is responsible for stretching the cervix as well as stimulating the nipples for milk production to occur. Women who do not go into labor naturally often require the use of Pitocin, which is the artificial form of oxytocin.


This hormone’s name indicates its function as it is responsible for relaxing certain parts of a pregnant woman’s body. Relaxin increases by about ten times through the duration of pregnancy, and it allows for the ligaments in the body to loosen. This is essential as the pelvic bones must have the flexibility to successfully allow the baby to pass through the birth canal. Relaxin also allows for the uterus to relax in anticipation of childbirth. This hormone can cause some women to become clumsy during pregnancy. Also, it is the cause of the feeling of looseness in some body parts such as the hips, ankles, knees, and shoulders that some pregnant women experience.


After pregnancy, women can produce milk to nourish their young. The hormone prolactin allows for this milk production to occur. Prolactin is produced in quantities 10 to 20 more times than when a woman is not pregnant. During pregnancy, prolactin ensures that the breast tissues are ready to be utilized. After pregnancy, the hormone allows the body to release milk through the nipples.

Pregnancy brings an entire cascade of hormones, all of which are required to perfectly orchestrate the amazing process of childbirth. These hormones can bring a variety of changes, many of which can be uncomfortable, to pregnant women. However, these effects are short-lived and usually thought of as being minor when compared to the amazing result of bringing a child into the world.