Deceased antithrombin (AT) levels, signifying a hypercoagulative state, have been reported in women with preeclampsia. Randomized trials of AT treatment have demonstrated significant improvement in maternal symptoms and preservation of fetal weight gain. The present report is a subgroup re-analysis of a randomized controlled trial of AT, given at 24 to 35 weeks’ gestation to women with severe preeclampsia, defined as a blood pressure exceeding 160/110 mm Hg despite bed rest and proteinuria greater than 2 g daily. Groups of 42 patients were randomly assigned to receive either 3000 IU of AT daily or an albumin placebo for 1 week. Fetal weight gain, heart rate, and biophysical profile scores were monitored up to the time of delivery.
Nearly two-thirds of women in each group completed the assigned intervention. AT treatment significantly countered worsening of both the fetal biophysical profile and the fetal heart rate (relative risk [RR], 0.24; 95% confidence interval [CI], 0.07–0.8) and increased the frequency of an estimated fetal weight gain exceeding 15 g/day during the week of treatment (RR, 3.1; 95% CI, 1.0–9.9). In addition, gestational age was lengthened to at least 34 weeks of gestation more often in the AT group (RR, 3.6; 95% CI, 1.05–12.6). Infant mortality rates were similar in the active treatment and placebo groups. No AT-related side effects were observed, and none of the women developed HELLP (eclampsia or hemolysis, elevated liver enzymes, low platelets) syndrome.
These findings show that AT treatment can prolong pregnancy in women with early-onset preeclampsia without adversely affecting the biophysical state of the fetus.