Treatment of hypertension in pregnancy: effect of atenolol on maternal disease, preterm delivery, and fetal growth

OBJECTIVE: To assess the impact of antihypertensive therapy initiated early in pregnancy on maternal and fetal outcomes. METHODS: A retrospective review of patients treated in early pregnancy with atenolol was conducted. Therapy was directed by measurements of cardiac output. Fetal growth was analyzed with reference to prior pregnancy outcome, treatment inconsistent with standards present at the end of the study period, and year of treatment. Data were analyzed by paired and unpaired t-test, analysis of variance for multiple comparisons, and linear regression. RESULTS: Two hundred thirty-five pregnancies at risk for preeclampsia were studied. Ten percent (n = 22) received additional therapy with furosemide; 20% (n = 48) with hydralazine. Six and one half percent had treatment inconsistencies. Fifty-five percent had greater than 100 mg of proteinuria at baseline. One patient developed severe preeclampsia. Only 2.1% delivered before 32 weeks; 4.7% delivered before 34 weeks. Low percentile birth weight was strongly associated with a prior pregnancy with intrauterine growth restriction (P = 0.001), treatment inconsistency (P <.001), and a pregnancy earlier in our treatment experience (P <.001). Percentile birth weight increased from the 20th at the beginning of the study period to the 40th by the end (P = 0.002). CONCLUSION: Early intervention with antihypertensive therapy was associated with a low rate of severe maternal hypertension and preterm delivery. The failure to adjust therapy in response to an excessive fall in cardiac output or increase in vascular resistance was associated with reduced fetal growth.