Scientists, including an Indian-origin researcher, have revealed that woman’s blood pressure before she gets pregnant could affect whether she has a boy or a girl.
Researchers led by Dr Ravi Retnakaran, endocrinologist at Mount Sinai Hospital in Canada found that while higher blood pressure was an indication that a boy was more likely to be conceived, women with lower blood pressure tended to give birth to a girl.
It was unclear whether a woman who wanted to have either sex could influence the outcome by deliberately raising or lowering her blood pressure.
The issue is controversial because of the practice of gendercide – in which female babies are aborted or even killed after birth – in some male-dominated societies.
This “suggests that a woman’s blood pressure before pregnancy is a previously unrecognized factor that is associated with her likelihood of delivering a boy or a girl,” said Retnakaran. “This novel insight may hold implications for both reproductive planning and our understanding of the fundamental mechanisms underlying the sex ratio in humans,” he said.
Beginning in February 2009, the team studied a group of women from Liuyang in China who were planning to get pregnant and used the model to evaluate the relationship between maternal pre-pregnancy health and the sex of the baby. The researchers recruited 3375 women, of these, 1692 women were assessed for blood pressure, cholesterol, triglycerides, and glucose.
After the exclusion of 281 women who were potentially pregnant at their baseline assessment based on back-dating of the length of gestation at delivery, the study population for the analysis consisted of 1,411 women who were assessed at median 26.3 weeks before pregnancy.
There blood pressure was tested before and after conception and other factors, such as age, whether they smoked, weight and cholesterol, were also taken into account.
The results indicated that 1,411 mothers had given birth to 739 boys and 672 girls. The findings indicate that those who had a female child had an average systolic blood pressure of 103.3mmHg before pregnancy, while for mothers of males the figure was 106, about 2.6% higher.
The study was published in the journal of American Journal of Hypertension.