Pregnant women are more likely to have baby girls when they are stressed

The effects of stress can lead to changes during pregnancy. The researchers found that this may increase their risk of miscarriage when pregnant with a boy, leading to more baby girls being born during stressful times.

The new study, published in the journal PNAS, highlights the effects of physical and psychological stress on babies in the womb. The researchers analyzed the health and lifestyle of 187 pregnant women aged 18 to 45.

Nearly 17 percent of participants reported high levels of depression, anxiety, and perceived stress, while 16 percent suffered from physical stress, such as persistent daily high blood pressure and increased caloric intake. The rest of the women are healthy.

After dividing participants into groups based on stress levels and causes, the researchers looked at indicators of mental, physical, and lifestyle stress. The women were surveyed, provided with diaries and underwent daily physical examinations.

The results showed that pregnant women had a lower chance of having a boy when they were suffering from physical or psychological stress. During stress periods, more girls are born. For mothers who are physically stressed, the ratio of births is 4:9 to male, while for psychologically stressed mothers, the ratio of births is 2:3.

Catherine Monk, principal investigator and professor of medical psychology at Columbia University's School of Vagus Neurology and Surgery, said in a press release: "In the wake of social unrest, other researchers have also seen this pattern.

For example, after the 9/11 attacks in New York City, the relative number of male births decreased. ”

She added: "Studies have shown that men are more susceptible to adverse prenatal environments. This means that pregnant women who are stressed due to the miscarriage of a previously pregnant boy are often less likely to give birth to a boy," she added.

The effects of maternal stress also increase the risk of preterm birth and reduce the development of the baby's central nervous system. The researchers also found that women who experienced psychological stress had more complications of childbirth than mothers who experienced physical stress.

Social support may play an important role during pregnancy. The team says women who are supported by family and friends during stressful times are more likely to have healthy baby boys.

"Screening for depression and anxiety is gradually becoming routine in prenatal check-ups," Munch said. "However, despite the small size of our study, the results suggest that strengthening social support may be an effective goal of clinical intervention."