Hormones and Pregnancy - What a Ride!
There a few times in life when a woman experiences the effects of hormones on the rampage. One time is at puberty and the rest come in adulthood with pregnancy and then later again with menopause. Fortunately for everyone concerned, the impact of hormones during pregnancy lasts for nine months or so - and it's a good thing. Hormones may have gotten a bad rap in the past, being blamed for just about anything and everything in a woman's life. However, this time, during pregnancy, hormones are guilty as charged.
In The Beginning
To begin with, even before conception, the body produces two hormones that harmonize together to orchestrate the release of the mature egg into the fallopian tube and signal the uterus to prepare for a visitor. These hormones are called luteinizing hormones (LH) and follicle stimulating hormone (FSH), both of which are produced in the pituitary gland. FSH stimulates the maturing of the follicle which contains the egg in the ovary, generating the production of estrogen. Estrogen signals the uterine lining to build up and then shuts down the production of FSH as it releases LH to burst the follicle and release the egg. The burst follicle sends out progesterone, the hormone that ensures everything is in place for a fertilized egg to grow, ripening the lining of the uterus and stopping LH production. Now the egg is in the fallopian tube and ready for that lucky sperm to arrive. Wow!
When contact is made and the sperm fertilizes the egg, another hormone arrives on the scene. The hormone human chorionic gonadotropin (hCG) is called the pregnancy hormone and is the product of the newly developing placenta. hCG is responsible for the increase of estrogen and progesterone production, getting the hormonal ball into motion. When a woman takes a pregnancy test to determine if she's pregnant, the pregnancy test hormones that are measured are hCG. HCG levels rise rapidly during the first few months of pregnancy and the doctor will monitor pregnancy hormone levels through the pregnancy in order to keep up with the baby's growth and progress. Those lovely pregnancy mood swings and other delights such as morning sickness are the result of hCG levels on the rise. The good news is that by the beginning of the second trimester hCG levels begin to decrease and some of the early pregnancy symptoms caused by hormones decrease as well. Although, pregnancy mood swings seem to stay around for a while.
Estrogen, The Mother Of Hormones
Estrogen, the mother of all female hormones, oversees the growth of the uterus and maintains the lining where the baby is safely housed. It causes blood circulation to increase and initiates the production of other key hormones needed throughout the pregnancy. Estrogen is responsible for those blooming breasts and is key to the production of the milk supply when baby is born. Estrogen also causes skin sensitivity and pigment coloration changes. That's why the areola (the area around the nipple) may darken, and why some women have a "pregnancy mask", darkening skin on the forehead, cheeks and nose.
Progesterone - The Big Kahuna
Estrogen's running buddy is progesterone, another product of the ovaries. Progesterone is responsible for the proper function of the placenta (where baby takes nourishment), and it also stimulates breast tissue. Progesterone, along with the hormone relaxin work together to relax and allow for the uterus to grow and expand as they soften cartilage and loosen joints and ligaments. Some of the pregnancy symptoms hormones generate include those delightful GI issues; constipation, bloating, gas, heartburn, indigestion and in late pregnancy, aching in the pubic bone and hips. Add acne, gum bleeding, and pregnancy gingivitis to the list of progesterone-induced pregnancy hormone level challenges.
Other Hormones Working Together
The hormone that triggers labor is called oxytocin, pregnancy's muscle-contracting hormone. The further along in pregnancy, the greater the sensitivity to this particular hormone. When the cervix is ripe and the baby is ready to make an appearance, oxytocin increases and contractions start. This hormone is also responsible for the involution, or shrinking, of the uterus after the baby is born and is released again when the baby begins to suckle, causing the muscles in the breast to contract and squeeze out milk.
There are many significant hormones involved in this wonderful creative experience, including prolactin, the body's main milk producer and placental growth factor, the lack of which is key in a condition called pre-eclampsia (high blood pressure during pregnancy). Growth hormones, thyroid stimulating hormone, insulin, cortisol, and prostaglandins are all important hormones and have explicit functions to ensure a pregnancy goes exactly as it should.