New York, Sep 9 (IANS): Researchers, including one of Indian-origin, have found that the rate of blood pressure (chronic hypertension) among pregnant women aged 35 and over in the US has increased by more than 75 per cent since 1970, according to a new research.

In the study, published in the journal Hypertension, researchers looked at the pregnancies of more than 151 million women in the US between 1970-2010.

"Women are having children later than in the 1970s and 1980s - and are experiencing higher rates of hypertension during pregnancy as a result," said the study led by author and Indian origin researcher Cande V. Ananth from Rutgers University.

According to the researchers, advanced maternal age was associated with the increase, with the rate of chronic hypertension increasing on an average by six per cent per year, 13 times what it was in 1970.

Prior research has shown that compared with white women, black women have higher rates of obesity, are more likely to smoke and use drugs and are at greater social disadvantage, all of which may contribute to an increased risk of chronic hypertension.

"The best outcome would be to control hypertension before becoming pregnant by reducing obesity, quitting smoking, adopting an overall healthier lifestyle before and during pregnancy, and treating high blood pressure effectively. For every 1-2 lbs. lost prior to pregnancy, blood pressure is reduced," Ananth said.

"Not only do these findings have implications for the health of the women and newborns during pregnancy, they have lasting implications on future risks of cardiovascular and stroke risks in women later in life," he added.