Mom's high BP tied to greater preterm survival

By David Douglas

NEW YORK (Reuters Health) - Pregnancy-induced hypertension (PIH) is associated with lower infant mortality in preterm infants, Canadian researchers have observed.

Study investigator Dr. Shi Wu Wen told Reuters Health that PIH might serve some adaptive role for the fetus in the face of trouble.

However, "it's important to stress that the findings should not be viewed as an encouragement not to treat PIH." The risks of such a course outweigh any potential benefits, Wen, from the University of Ottawa, said.

PIH is a generic term that encompasses a variety of conditions including pre-eclampsia -- a complication of pregnancy characterized by elevated blood pressure -- and may affect as many as 10 percent of pregnancies. It can lead to substantially increased morbidity for mom and infant.

Nevertheless, the researchers point out that the influence of PIH has not been adequately studied, particularly in infants who are born prematurely.

Therefore, Wen's team examined data on more than 17 million live born singleton US births between 1995 and 2000.

They found a significant reduction in infant mortality associated with PIH in "early preterm" and "late preterm" infants. However, PIH was associated with significantly increased mortality in term infants.

With PIH, there also was a reduction in early and late neonatal mortality both in early preterm births and late preterm births.

Overall, say the investigators, the PIH-associated reduction in neonatal mortality was stronger in smaller-than-normal infants than in normal growth infants and stronger in infants born to first-time mothers than in those born to women who previously delivered an infants.

SOURCE: British Journal of Obstetrics and Gynaecology, May 2006.

BJOG 2006;113:544-551.