Pregnancy is a time when your hormones change drastically. These hormones are the reason you feel the way you do, both physically and emotionally, and are what allows a pregnancy to make it to term and promote a healthy mother-baby relationship afterwards. It is valuable to know about each of the hormones involved because they can have an effect on emotional wellbeing.
Progesterone slowly rises throughout the nine months of pregnancy, and then sharply drops off at delivery. This sharp decline is one of the mechanisms that leads to postpartum depression in vulnerable women. Progesterone is considered one of the “gonadal steroids” or “sex steroids” (the other one being estrogen). One progesterone metabolite, allopregnanolone, is hypothesized to be particularly involved in regulating mood and anxiety. The research on this metabolite is early, with most of the data in animal studies, but it seems to be able to create an antidepressant and antianxiety effect in the body.
This is the other sex steroid and it also rises throughout pregnancy, with a sharp drop off at delivery. This hormone affects hundreds of different human body functions, including brain function and therefore mental health. One of the ways it affects mood is by acting with serotonin, one of the molecules thought to be responsible for the development of depressive and anxiety conditions (and the main molecule used to treat these conditions with medications such as fluoxetine/Prozac and others). Like progesterone, the drop off of estrogen immediately postpartum is one possible trigger for postpartum depression in vulnerable women.
This is a chemical secreted in the brain which has affects throughout the body. These effects include decreases in anxiety and stress. Oxytocin is also thought to play an important role in maternal behavior, such as the amount of attention a new mom shows her infant and their attachment/bonding relationship. From a physical perspective, it can help the uterus return to its normal size postpartum.
Cortisol is known as the “stress hormone.” In pregnancy, the levels of cortisol rise gradually until by the end of pregnancy they are 2-3 times the average of non-pregnant women. Many studies have attempted to determine if high or low levels of cortisol or changes in the daily cycles of the hormone are associated with depression. The results are mixed. Researchers hypothesize that there are different forms of postpartum depression, some of which are hormonally mediated and are associated with changes in cortisol function. Data (early and primarily in animals) also suggests that increased cortisol exposure by a fetus impacts cognitive development, which is why researchers are continuing to study this essential hormone.
There are, of course, many other contributing hormones in a woman’s reproductive cycle – precursors, metabolites, and relatives of the above, as well as neurochemicals and other important active molecules. While this is not an all-inclusive list, it is a good place to start a conversation about the impact of hormones on mental health.
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Douma, S.L. et. al. Estrogen-related mood disorders: Reproductive Life Cycle Factors. (2005) Advances in Nursing Science 28(4): 364-375.
Schule, C., Nothdurfter, C., Rupprecht, R. The role of allopregnanolone in depression and anxiety. (2014) Progress in Neurobiology 113: 79-87.
Iliadis, S. I. et. al. Prenatal and postpartum evening salivery cortisol levels in association with peripartum depressive symptoms. (2015) PLOS One 10(8).
Bergman, K. et. al. Maternal prenatal cortisol and infant cognitive development: moderation by infant-mother attachment. (2010) Biological Psychiatry 67: 1026-1032.