When High Blood Pressure Mixes with Pregnancy

Chronic hypertension linked to pregnancy complications

/ Author:  / Reviewed by: Joseph V. Madia, MD Beth Bolt, RPh

(RxWiki News) Chronic health conditions in women can influence the course of a woman's pregnancy. High blood pressure is one condition that presents risks to pregnant women.

A recent study pulled together all the research available related to pregnancy and high blood pressure.

The results revealed an increased risk with high blood pressure for C sections and pre-eclampsia.

Pre-eclampsia is a pregnancy complication that requires delivery of the baby to treat it. Untreated pre-eclampsia can lead to stroke.

Other risks from high blood pressure during pregnancy included having a baby early and/or with a low birth weight.

"Attend all prenatal appointments."

This study, led by Kate Bramham, a clinical research fellow in the Division of Women's Health at King's College London in England, analyzed the research related to pregnancy complications from high blood pressure.

The researchers searched three major medical research databases for all studies up through June 2013 related to hypertension and pregnancy. They identified 55 studies that met their criteria, involving 795,221 women's pregnancies.

The results showed that having chronic high blood pressure was linked to a range of pregnancy complications. These complications included pre-eclampsia, cesarean section delivery, preterm birth, low birth weight and an increased risk of infant death.

Approximately 26 percent of women with chronic hypertension experienced pre-eclampsia, a rate 7.7 times higher than the pre-eclampsia rates found in the general population of pregnant women.

About 41 percent of women with chronic high blood pressure needed a C section, a rate 2.7 times greater than the general population's rate.

Further, 28 percent of women with chronic hypertension gave birth early (before 37 weeks), a rate 2.7 times greater than that of the general population.

About 17 percent of women with high blood pressure gave birth to babies with a birthweight below 5.5 pounds, a rate three times greater than that of the general population.

Finally, 4 percent of the women with high blood pressure had a newborn who died, a rate about four times higher than that found in the general population.

In pregnant women with chronic high blood pressure, "adverse outcomes of pregnancy are common and [this] emphasizes a need for heightened [prenatal] surveillance," the authors wrote.

According to Andre Hall, MD, an OBGYN at Birth and Women's Care, PA in Fayetteville, NC, chronic hypertension is defined as an elected blood pressure before 20 weeks gestation. It is a significant risk factor for both mom and a developing pregnancy, he said.

"Hypertension predisposes the fetus to higher pressures in what is normally a low pressure system," Dr. Hall said. "This leads to potential problems with developing organs and leads to babies that are intrauterine growth restricted (IUGR)."

The consequences of this condition can last long beyond birth, he noted.

"Women are also at risk as poorly controlled blood pressures can also lead to organ failure, heart attacks and strokes," Dr. Hall said. "The key point is that careful attention needs to be paid to the blood pressure issues and this can only be done by attending regular prenatal visits."

This study was published April 15 in the journal BMJ. The research was funded by the National Institute for Health Research. No conflicts of interest were reported.

Review Date: 
April 15, 2014
Last Updated:
April 24, 2014