Estrogen and progesterone rise and fall throughout the menstrual cycle and during life stages like pregnancy and menopause, according to Cielo Gnecco, MD, an ob-gyn with Orlando Health Women’s Institute Center for Obstetrics and Gynecology in Kissimmee, Florida.
“These hormones directly affect brain chemicals that control mood, energy, sleep, and emotional regulation,” she says. “Estrogen generally supports mood by helping serotonin and dopamine work more effectively, which can improve emotional stability and resilience. Progesterone has a calming effect on the brain, but when its levels drop quickly, that calming effect can disappear suddenly.”
In people with bipolar disorder, whose brain chemistry is already more sensitive, these hormonal shifts can make mood regulation harder and increase the risk of depression, irritability, anxiety, or mood swings, Dr. Gnecco explains.
“The thirties and forties are often considered a vulnerable time for women with bipolar disorder because hormone patterns start to become less predictable during these years,” she says. “Ovulation may not occur consistently, and estrogen levels can fluctuate more from month to month, even before menopause begins.”
At the same time, many women in this age group experience competing responsibilities of work, childcare, and sometimes caring for aging parents. That can mean more stress and disrupted sleep. These biological and life factors together can lower mood stability and make bipolar symptoms more likely to emerge or worsen, Gnecco adds.