Changes in hormone levels These two hormones can have a significant impact on one's mental wellbeing. Estrogen affects the whole body and is active in the brain area that governs emotions, so it's no surprise that this hormone is linked to anxiety, irritability, and sadness. Progesterone has its main effect on the uterus, but it also plays a role in regulating emotion by acting on the brain's adrenal gland. When progesterone levels are high, women tend to be more calm and relaxed. Women who find themselves under a great deal of stress may benefit from talking with their doctor about taking hormonal birth control pills or using another form of contraception that does not depend on their own ability to regulate their hormones. The best time to start taking hormones is while you're still pregnant - the effects will help keep you calm and relaxed at a time when you need it most.