A Guide to Hormones and Mood Changes in the Pregnancy & Postpartum
When you think about your mood and emotions during pregnancy and postpartum, what comes to mind? Maybe mood swings, a mix of conflicting feelings—joy, anticipation, and hope, alongside frustration, overwhelm, or even disappointment at times. But do you know what’s behind this emotional rollercoaster?
While environmental, social, and psychological factors are certainly at play, another important piece of the puzzle includes the physiologic changes of early motherhood. Specifically, there are major hormonal and neurochemical changes that happen during this time. But the reality is, routine prenatal care doesn’t typically provide extensive information about these physical changes in a way that helps women understand the range of emotions they might feel and when they might experience those effects.
Recognizing the mind-body connection between these physical shifts and your emotional state can help you better navigate the ups and downs of early motherhood. Hormones drive so much of both the physical and psychological changes that you experience during pregnancy and postpartum. Let’s shine a light on these important chemical messengers so that you can better understand why you're feeling the way you feel, and know what to expect on the road ahead.
Hormones are little messengers that travel through your body telling organs and glands what functions need to be performed. Let's talk about 4 of the key hormones during your pregnancy and postpartum recovery, and how they impact mood and mental state.
Estrogen/Progesterone:
First off, estrogen and progesterone are closely linked to emotions and mood changes. The way they actually impact mood is by influencing chemical messengers in the brain called neurotransmitters, which include mood-lifting neurotransmitters like dopamine and serotonin.
So hormone changes directly impact this "communication network" in your brain. During the perinatal period, these hormones fluctuate drastically. For example, a woman will produce more estrogen during one pregnancy than throughout her entire life when not pregnant! When your estrogen and progesterone are at an all-time high at the end of pregnancy, you get a nice little bump in dopamine and serotonin - this is the "baby bliss" some people experience at the end of 3rd trimester. But then in just the first 24 hours after delivery, estrogen and progesterone plummet to near pre-pregnancy levels, and this rapid drop can cause fluctuations in dopamine and serotonin, causing major mood swings and depressive symptoms - this plays into the "baby blues" that up to 80% of birthing mothers experience.
It is the rise and fall of these hormones that can often cause mood changes. Typically around three-six months postpartum, estrogen and progesterone return to around pre-pregnancy levels.
Oxytocin:
Oxytocin is your “love and lactation” hormone. It is related to nesting behaviors and also part of the “baby bliss” feelings toward the end of pregnancy. Then in the postpartum, it’s related to maternal-infant bonding and lactation. You know that feeling when you hold your little one and get a tingling sensation in your breasts and feel milk flushes? Oxytocin is responsible!
Even though we think of oxytocin as the “bonding” hormone, the initial quick drop after birth is thought to play a role in the feelings of “baby blues” during the first few days after delivery. But your body adjusts to the fluctuating levels, and typically mood is not significantly impacted by these fluctuations until you begin weaning. During weaning, the rapid drop can again cause a dip in mood (this is referred to as “post-weaning depression”). You can make this transition easier for yourself by taking it slow, gradually reducing feedings by 1-2 daytime feedings per week, and replacing feedings with skin-to-skin snuggle time to help promote oxytocin release so levels can continue to fall more gradually.
Cortisol:
Cortisol is a hormone essential for regulating stress responses like the “fight or flight” response. However, it is also involved in many other types of stress responses in your body including "normal" physical stressors like rigorous exercise… or labor! It peaks at the end of pregnancy to help with labor-related stress, so it's appropriate for levels to be elevated at that time.
However, it can have some downsides when it comes to emotions and mood. Too much cortisol can be associated with a state of “constant high alert,” anxiety, irritability, and other mood changes. Many studies have attempted to determine if and how cortisol levels are associated with perinatal mood and anxiety disorders (PMADs). While the results are mixed, researchers have hypothesized that there are different forms of postpartum depression and anxiety, and that some forms are indeed hormonally mediated and associated with changes in cortisol function.
While this article covered some of the key hormones involved in the perinatal period, it’s not an exhaustive list. My hope is that this information provides insight and a sense of reassurance during what can be a confusing time. The next time you find yourself on the “emotional rollercoaster,” remember that it’s not just about adjusting to life with a newborn, sleep deprivation, or the many stressors of early motherhood. It’s all of those things—plus the intense highs and lows of hormonal and neurochemical shifts happening in your maternal brain and body. And while you may not be able to change these fluctuations, there is comfort and clarity in understanding their impact.
For much more on this topic, check out my foundational course for new moms!
References:
Iliadis, Stavros I et al. “Prenatal and Postpartum Evening Salivary Cortisol Levels in Association with Peripartum Depressive Symptoms.” (2015) PloS one vol. 10,8
Douma, S.L. et. al. Estrogen-related mood disorders: Reproductive Life Cycle Factors. (2005) Advances in Nursing Science 28(4): 364-375.
Dong-ni Pan, et al.What a difference timing makes: Cortisol effects on neural underpinnings of emotion regulation. (2023) Neurobiology of Stress, vol. 25