A team of researchers from Quebec and London conducted a study to determine the effects of aspirin on preeclampsia or PE, a condition characterized by high blood pressure that occurs during pregnancy, and fetal growth restriction or FGR, when fetal weight is below the 10th percentile, presents a hefty burden on maternal and fetal health, while putting the pregnancy outcome at risk.
Preeclampsia can put the mother at risk of premature cardiovascular disease, such as stroke and chronic hypertension later in life. After preeclamptic pregnancy, a newborn with a low birth weight will have an increased risk of coronary heart disease and stroke in adult life. Since preeclampsia can cause abnormal placentation, which is linked to events occurring in the first trimester of pregnancy, it can have a complex pathophysiology.
The team of researchers examined randomized controlled trials or RCTs to decide the exact phase of pregnancy that the optimal dosage of aspirin should be introduced to the mother to decrease the risk of preeclampsia. Meta-analysis and systematic review were the methods utilized for the study. The new study examined a total of 45 studies that included 20,909 women, who were pregnant. Those women were given a placebo (no treatment) or aspirin beginning after, before or at 16 weeks of gestation.
The findings revealed that the women, who started taking aspirin before or at 16 weeks of gestation showed lower risk of fetal growth restriction and preeclampsia than the women, who started taking aspirin after 16 weeks of gestation. The researchers also discovered that the greater the dose, the greater the decrease in the risks of PE and FGR, before or at 16 weeks of gestation.
The findings in the new study validate previous studies and therefore yield evidence that aspirin can prevent PE and FGR. However, the studies conclude that aspirin needs to be given before or at 16 weeks in order to prevent the conditions in high-risk women. Simultaneously, the findings confirmed that the effects of aspirin on the prevention of FGR and PE are optimal and dose dependent.
The small groups of RCTs placed limitations on study, which could make it biased and difficult to determine the optimal dose of aspirin. The researchers note that further studies are needed to determine the mechanism whereby aspirin acts to prevent FGR and PE.
The study was published in the American Journal of Obstetrics and Gynecology in February 2017.