Stressed Pregnant Moms Are Less Likely to Have Boys, New Study Finds

A pregnant woman in a stock photo. (Illustration - Shutterstock)

Pregnant women are less likely to have boys if they experience physical and psychological stress, a new study has revealed.

Researchers at the National Academy of Scientists found that stressed moms-to-be were less likely to give birth to boys and may also have a higher risk of preterm birth.

“The womb is an influential first home,” lead author Catherine Monk, director of women’s mental health in OB/GYN at New York-Presbyterian/Columbia University Irving Medical Center, told CNN.

“We do know that males are more vulnerable in utero, and presumably the stress in these women is of a long-standing nature,” Monk said.

The study tracked 187 pregnant women, aged from 18 to 45, to determine how maternal prenatal stress influenced offspring neurodevelopment and birth outcomes.

Researchers say that on average, nature typically assures around 105 boys are born for every 100 female births.

However, the study found that four boys were born for every nine girls when the mother had high blood pressure.

Meanwhile, expectant moms who were psychologically stressed had two boys for every three girls, and the risk of premature birth also increased.

“Other researchers have seen this pattern of a decrease in male births related to traumatic cataclysmic events, one of them being President Kennedy’s assassination and the other being the September 11 terrorist attacks in New York City,” Monk said.

The opposite results were seen in pregnant women who received support from family and friends, with the risk of premature delivery disappearing and the chance of having a male increasing.

On this startling discovery, Monk said: “The support could be from family and friends. It could be a sense of belonging in a religious community.

“It’s the sense of social cohesion and social connectedness which research suggests is a buffer against the experiences of stress. It means you take a break from it.”

Dr. Christina Penfield, an assistant professor of maternal-fetal medicine at New York University Langone Medical Center, said social support is critical for building confidence in a new mom.

Penfield, who was not involved in the study, told CNN: “Pregnancy is a pivotal moment in women’s lives coinciding with a redefinition of self, family, and community.

“It is therefore not surprising that several studies have demonstrated that when we provide social support programs to pregnant women we see improvements in their psychosocial outcomes.”

According to a study from the Department of Psychology at Tilburg University in the Netherlands, an estimated 30 percent of pregnant women report psychosocial stress from job strain or depression and anxiety.

Despite the findings, researchers emphasized that stress during pregnancy is completely normal and pregnant women who ensure they get plenty of sleep, eat a healthy diet, and exercise can minimize the effects of stress.