Curiously, many men report pregnancy symptoms alongside their female partners, often mirroring their partner’s experiences of nausea, fatigue, pain, appetite changes, and weight gain. This phenomenon, termed Couvade syndrome, is the most common in cultures where men spend more time caring for infants and where couple intimacy is high. But why do men experience these symptoms? Storey et al. (2000) examined the physiological mechanisms for Couvade syndrome by measuring the hormones and responses to infant stimuli of expectant couples.

The researchers recruited 34 couples from prenatal classes in Canada. Of these couples, 31 were first-time parents. During various phases of pregnancy, couples participated in situational reactivity tests that examined their self-reported and hormonal responses to infant stimuli. In tests administered before birth, couples contributed blood samples and then held a doll that was wrapped in a blanket recently worn by a newborn. The researchers then played a 6-minute tape of infant cries and a 5-minute clip of a video called “Breast Is Best,” which depicted an infant nursing for the first time. For the remainder of the 30-minute break between blood samples, the researchers conversed with the couples, noting if anyone put down the doll. The second blood sample was taken to indicate short-term changes in hormones from the infant stimuli. Situational reactivity tests administered after birth were slightly different—while the father held the doll, the mother held their baby. At the session, couples also completed questionnaires about pregnancy symptoms (e.g., weight gain, fatigue, changes in appetite), their responses to the infant stimuli (e.g., feeling anxious, content, concerned), and their stress.

Results indicated that men and women showed similar shifts in hormones through the pregnancy. Both had higher levels of prolactin and cortisol just before birth and lower levels of sex hormones (testosterone in men and estradiol in women) after birth. Men who had larger shifts in prolactin and testosterone during the situational reactivity test reported more pregnancy symptoms. Men with higher prolactin or lower testosterone held the doll for more time and were more responsive to the infant stimuli. Furthermore, partners had similar hormone levels.

The researchers concluded that Couvade syndrome may help prepare men for infant care. For instance, prolactin, which rose through pregnancy for men and women, encourages parental behavior. Cortisol, which also peaked in late pregnancy, predicts greater attachment between mothers and infants. However, high cortisol could also be due to stress. Testosterone, which decreased over the course of pregnancy and birth, has been found to impede nurturing behaviors while increasing competitive goals. Therefore, as the researchers found, lower testosterone should lead to greater responses to infant stimuli. Finally, the correlation between the men's and women’s hormone levels indicates that their relationship influences men’s hormonal changes. In fact, while women’s hormones were closely related to the stage of pregnancy, men’s more closely tracked their female partner’s hormones.

Therefore, while it may be difficult for women to navigate both their own and their partner’s pregnancy symptoms, the latter can be a good sign, indicating that their partner feels close to them and is also preparing (perhaps unwittingly) to be a loving parent.