By David Douglas
WESTPORT, CT (Reuters Health) – Antihypertensive therapy begun early in pregnancy can improve outcome, but less than optimal treatment may lead to reduced fetal growth, researchers report in the September issue of Obstetrics and Gynecology.
Dr. Thomas R. Easterling and colleagues at the University of Washington in Seattle conducted a retrospective review of women who were treated in early pregnancy with atenolol. The reason behind the study, Dr. Easterling told Reuters Health, is that "pharmacological treatment of blood pressure in pregnancy is controversial."
Overall, he said, "the patients that we treated had a very low rate of life-threatening maternal hypertension and preterm birth due to hypertension. However, they also had an elevated incidence of smaller babies than would be expected at the gestational age that they delivered."
In total, the researchers examined 235 pregnancies in which the mothers were at risk for preeclampsia. Furosemide was used as additional therapy in 10% and hydralazine was employed in 20%. One patient developed severe preeclampsia, 2.1% delivered before 32 weeks and 4.7% delivered before 34 weeks. "Percentile birth weight increased from the 20th at the beginning of the study period to the 40th by the end."
Two factors significantly contributed to the risk for reduced fetal growth, Dr. Easterling said. "First, women with prior pregnancies with small babies were at higher risk. Second, if we allowed the cardiac output to fall below the expected average cardiac output or if we allowed the blood vessels to constrict excessively, the risk for small babies was increased. As we learned to treat mothers to avoid these hemodynamic abnormalities, the average size of the babies increased significantly."
Treatment of hypertension can improve maternal and fetal outcome, the researchers conclude, and although "overtreatment can result in small babies," said Dr. Easterling, "careful intervention based on maternal blood flow characteristics can allow the physician to optimize pregnancy outcome and fetal growth."