Blamed for everything from mood swings to nausea, hormones during pregnancy get a bad rap. Many women think of pregnancy hormones as a group, but specific hormones peak at different times during pregnancy to fulfill specific purposes.
First detected by urine pregnancy tests 12 to 14 days after conception, human chorionic gonadotropin (hCG) is produced by cells that form the placenta. Typically, hCG levels double every 48 to 72 hours, peaking eight to 11 weeks into your pregnancy before leveling off. Your body's level of the hCG hormone plays a key role in allowing your obstetrician or midwife to check the health of your pregnancy. According to the American Pregnancy Association, low levels of hCG in your blood could indicate a miscarriage or ectopic pregnancy, whereas high levels of hCG in your blood could signify a multiple pregnancy or a molar pregnancy.
Initially produced by the corpus luteum (follicle that released your egg), progesterone plays a key role in preparing your uterus for the implantation of the fertilized egg. Following the first eight to 10 weeks of pregnancy, the placenta takes over progesterone production, which must be continued throughout pregnancy in order to help your body maintain the pregnancy. Progesterone production increases until right before birth and is responsible for keeping uterine contractions from occurring, decreasing prostaglandins and stimulating breast growth. The rapid decrease of progesterone right before birth helps trigger the uterus to begin contractions.
Similar to progesterone, estrogen is mostly produced by the placenta and increases in production throughout the duration of your pregnancy. Not only does estrogen help regulate your body's levels of progesterone, but it also contributes to the development of your unborn baby, triggering the growth of important organs such as the liver, lungs and kidneys. According to PaternityAngel.Com, estrogen also maintains healthy blood flow in your uterus and contributes to the development of your baby's reproductive organs and sexual characteristics.
Relaxin and Oxytocin
As your pregnancy progresses, your body's production of relaxin and oxytocin, two key hormones that affect your labor and delivery, also increase. Relaxin completes the twofold job of relaxing your pelvic ligaments and enlarging your cervix opening during labor. However, it also relaxes ligaments throughout the rest of your body, which can result in muscle and back pain. Your body's production of oxytocin peaks right before labor, which combined with the decrease in progesterone, results in uterine contractions. This hormone plays such a key role in the progression of your labor that women going through slow labors are often given injections of oxytocin to speed things up.
Following labor and delivery, hormone levels decrease drastically, which can cause strong mood swings, irritability and fatigue. According to the Mayo Clinic, although many women just experience the "baby blues," mild mood swings and feelings of fatigue, some women go on to develop postpartum depression or postnatal psychosis, serious postpartum conditions that need treatment.