First-trimester screening for fetal growth restriction and adverse maternal/perinatal outcomes.

Objective: To evaluate the association between first-trimester screening for fetal growth restriction (FGR) and the effect of aspirin use as prophylaxis for this condition, as well as its effect on adverse maternal and perinatal outcomes. A secondary objective was to evaluate the association between a high risk of FGR and adverse perinatal outcomes.

Materials and methods: This was a retrospective cohort study of pregnant women who did or did not undergo first-trimester screening for FGR. Screening for FGR involved the evaluation of maternal characteristics, mean arterial pressure, and the results of uterine artery Doppler. Pregnancies with an estimated risk ≥ 1:155 were categorized as high risk, whereas those with an estimated risk < 1:155 were categorized as low risk.

Results: We evaluated 499 pregnant women who did not undergo first-trimester screening for FGR (unscreened group) and 615 who did (screened group). The risk of gestational hypertension was lower in the screened group, as evidenced by an adjusted odds ratio (aOR) of 0.24 (95% CI: 0.14-0.39; p < 0.001), as was the risk of spontaneous preterm birth at < 37 weeks of gestation (aOR: 0.22; 95% CI: 0.10-0.45; p < 0.001). The risk of delivery at < 32 weeks was higher in the screened group (aOR: 8.25; 95% CI: 1.05-65.71; p < 0.045) as was the risk of delivery at < 37 weeks (aOR: 5.91; 95% CI: 2.62-13.31; p < 0.001). Among all of the pregnancies at high risk of FGR (in both groups), there was an increased risk of delivery at < 32 weeks (3.1% vs. 0.2%; OR: 16.20; 95% CI: 2.20-190.90; p = 0.004), and at < 37 weeks (10.7% vs. 1.4%; OR: 8.41; 95% CI: 3.60-22.10; p < 0.0001). The use of aspirin was associated with a greater prevalence of gestational hypertension (8.0% vs. 2.1%; OR: 4.1; 95% CI: 1.77-10.10; p = 0.0014) and of a birth weight < 2,500 g (14.5% vs. 7.3%; OR: 2.14; 95% CI: 1.25-3.71; p = 0.009).

Conclusion: First-trimester screening for FGR seems to be associated with a higher risk of preterm birth (at < 32 and < 37 weeks). Pregnancies that are at high risk of FGR appear to also be at a higher risk of adverse perinatal outcomes. Aspirin use seems to be associated with a greater prevalence of developing gestational hypertension and of a birth weight < 2,500 g.