Maternal Hypertension Tied to Greater Preterm Survival

[Anil Tuladhar]

Pregnancy-induced hypertension (PIH) is associated with lower infant mortality in preterm singletons, Canadian researchers report in the British Journal of Obstetrics and Gynaecology.

Dr. Shi Wu Wen of the University of Ottawa and colleagues note that PIH is a generic term that encompasses a variety of conditions including pre-eclampsia and may affect as many as 10% of pregnancies. It leads to substantially increased maternal and perinatal morbidity.

Nevertheless, the researchers point out that the influence of PIH has not been adequately studied, particularly in preterm births.

In order to help do so, the researchers examined data on more than 17 million liveborn singleton US births between 1995 and 2000.

The researchers found a significant reduction in infant mortality associated with PIH in early preterm infants (odds ratio, 0.59). This was also true of late preterm infants (odds ratio 0.80). However, PIH was associated with significantly increased mortality in term infants (odds ratio, 1.08).

With PIH, there also was a reduction in early neonatal mortality both in early preterm births (odds ratio, 0.38) and late preterm births (odds ratio 0.68). For late neonatal mortality, the corresponding ratios were 0.59 and 0.76.

Overall, say the investigators, the PIH-associated reduction in neonatal mortality was stronger in small-for-gestational-age infants than in normal growth infants and stronger in infants born to nulliparous women than in those born to multiparous women.

Dr. Wen told Reuters Health that PIH might serve some adaptive role for the fetus in the face of uroplacental dysfunction. 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.

[Soul]

This study is really surprising and hard to believe. Few days ago I read an article where it was reported that delayed umbilical cord clamping (after 3 minutes) at birth reduces neonatal anemia. We used to clamp the umbilical cord immediately after birth. I wont wait for 3 minutes despite reading this article.

[Anil Tuladhar]

I agree that this is interesting but very dubious study. But it is also an observational retrospective study. Hence, nobody will not treat Pregnancy induced hypertension just to improve the outcome of preterm babies (as this study indicate) and it would be unethical not to do so. The authors also conclude that "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.