FROM OBSTETRICS & GYNECOLOGY
The use of antiplatelet agents in pregnant women at risk for preeclampsia reduces the risk of spontaneous preterm birth by about 7%, while moderate to very preterm birth at less than 34 weeks of gestation is reduced by 14%.
Those are key findings from a meta-analysis of data from 17 trials that evaluated the effect of antiplatelet agents to reduce preeclampsia.
“Preterm birth is one of the most challenging obstetric problems worldwide and occurs in approximately 5%-12% of all deliveries,” wrote Elvira O. G. van Vliet, MD, PhD, of University Medical Centre Utrecht, the Netherlands, and her colleagues. “An increasing body of evidence suggests that uteroplacental ischemia … plays a role in the etiology of spontaneous preterm labor, analogous to its role of preeclampsia. Placental vascular pathology is found in at least one-third of the placentas of women with spontaneous preterm labor or prelabor PROM.”
In an effort to evaluate the efficacy of low-dose aspirin for the prevention of spontaneous preterm birth in women at risk for preeclampsia and to explore the effect in prespecified subgroups, the researchers assessed results from the Perinatal Antiplatelet Review of International Studies Individual Participant Data meta-analysis, which comprised 31 studies that randomized women to low-dose aspirin/dipyridamole or placebo/no treatment as a primary preventive strategy for preeclampsia.
For the current study, researchers from the Netherlands and Australia analyzed data from 17 of the 31 trials that supplied data on type of delivery (spontaneous, compared with indicated birth), which included a total of 28,797 women. The study’s primary endpoints were spontaneous preterm birth at less than 37 weeks, less than 34 weeks, and less than 28 weeks of gestation (Obstet Gynecol. 2017;129:327-36).
Compared with women who received placebo/no treatment, women assigned to antiplatelet treatment had a lower risk of spontaneous preterm birth at less than 37 weeks’ gestation (relative risk, 0.93) and at less than 34 weeks of gestation (RR, 0.86). The relative risk of having a spontaneous preterm birth at less than 37 weeks was even lower for those who had a previous pregnancy (RR, 0.83).
The number needed to treat to prevent 1 case of spontaneous preterm birth at less than 37 weeks’ gestation was 139. The number needed to treat was 242 for spontaneous preterm birth at less than 34 weeks’ gestation.
The researchers noted certain limitations of the analysis, including the potential for the possibility of inconsistency in the definition of spontaneous preterm birth between studies. “Because antiplatelet agents in pregnancy are a low-cost and safe intervention, we suggest that antiplatelet agents may also be a promising intervention for women at high risk for a spontaneous preterm birth, especially in high-risk women with a previous pregnancy,” they wrote. “The current study provides clinicians with the best available evidence to counsel women regarding who might benefit from this intervention.”
The researchers reported having no potential conflicts of interest. Dr. van Vliet was supported by a travel grant of the Dutch Ter Meulen Fund of the Royal Netherlands Academy of Arts and Sciences.