A boy or a girl? Mum’s blood pressure holds hey

FOR centuries people have tried to guess whether pregnant women are having a boy or girl.

Bad morning sickness, the shape of the bump or food cravings all have their champions as a clue to the child’s gender.

But now scientists say a woman’s blood pressure before she even conceives might be the most accurate indicator of all.

The research, led by experts in Canada, suggests women with slightly higher blood pressure are more likely to give birth to a boy, and those with slightly lower blood pressure are more likely to give birth to a girl. T hey think this is because blood pressure affects the likelihood each gender will survive the pregnancy.

The chance of a foetus being male or female at the point of conception is 50: 50, but the chance of each gender surviving to full term depends slightly on the mother’s blood pressure.

Experts are not exactly sure why boys are more likely to survive with high blood pressure, and girls with lower blood pressure. But they suspect it might be because ‘frail’ male foetuses are less able to deal with the stress of dealing with low blood

pressure, which affects the formation of the placenta and blood vessels in early pregnancy.

Writing in the American Journal of Hypertension, the authors said this might be why female birth rates increase in difficult times. They added: ‘For example, population stressors such as natural and man-made disasters, terrorist attacks, and economic collapse have all been reported to decrease the proportion of boys at birth, potentially due to greater spontaneous loss of male foetuses under these adverse conditions.’

Professor Adam Balen, of the British Fertility Society and spokesman for the Royal College of Obstetricians and Gynaecologists, said: ‘The sex of a baby is determined by the sperm – that is whether it has an X or a Y chromosome – so why maternal blood pressure should have an influence is intriguing and baffling.’