A new report suggests that male babies are more likely to be born from a prolonged pregnancy than females. Based on the most recent data, a pregnancy is deemed prolonged if it lasts 41 weeks or longer. Prolonged births can lead to an increased risk of health problems, or death. In some prolonged pregnancy cases, a rare enzyme deficiency in males may lead to the fetus producing too little estrogen, which prolongs the pregnancy. Investigators at Lenox Hill Hospital, in partnership with Sweden’s Karolinska Institute, recently found that, on average, males spent about one day longer in the womb than females. To see if prolonged pregnancy is related to gender itself, the researchers studied over 600,000 babies born in Sweden between 1987 and 1996. They found that 26.5 percent of the male babies were born at 41 weeks, compared to 22.5 percent of females. Only 7.6 percent percent of male babies and 5.5 percent of female babies were in the womb 42 weeks or longer. Males were also 1.5 times more likely to be born at 43 weeks or longer. The researchers noted that the most common reason for prolonged pregnancies is an error in calculating the due date. Women who are having their first child or have delivered prolonged pregnancy children in the past are also more likely to have a prolonged pregnancy; fetal abnormalities also lead to prolonged pregnancies, they found. The researchers acknowledge that the results might have been different if conducted in North America or other ethnically diverse populations, or those with different obstetric practices. However, the results raise the possibility that gender-specific mechanisms are involved in the initiation of labor and delivery.
