More adverse outcomes seen with fetal growth restriction even when prenatally resolved

Key takeaways:

• Pregnancies with resolved or persistent fetal growth restriction had increased adverse perinatal outcomes.
• Findings were continual for pregnancies with resolved or persistent fetal growth restriction.

Neonates with prenatally resolved fetal growth restriction continue to have increased risks for adverse perinatal outcomes, according to study results published in the American Journal of Obstetrics and Gynecology.

“Fetal growth restriction (FGR) is associated with an increased risk of adverse maternal and perinatal outcomes. In our experience, prenatal sonographic resolution of FGR commonly occurs,” Luke N. Roberts, MD, resident physician in the division of maternal-fetal medicine in the department of obstetrics and gynecology at Maine Medical Center, and colleagues wrote. “Considering that maternal and perinatal outcomes in these pregnancies have not been widely studied, we compared the outcomes of these pregnancies to those without FGR and those with persistent FGR.”

Roberts and colleagues conducted a retrospective cohort study with data from 359 singleton pregnancies from women who delivered at a single institution from 2020 to 2022. Researchers identified pregnancies with FGR diagnosed at 26 weeks or more gestation by fetal abdominal circumference and/or estimated fetal weight below the 10th percentile for gestational age. The reference group consisted of every two consecutive pregnancies without FGR identified after each index FGR pregnancy.

Primary outcomes were one or more of the following adverse perinatal outcomes:

• fetal or neonatal death;
• seizures;
• respiratory distress syndrome;
• necrotizing enterocolitis;
• intraventricular hemorrhage;
• sepsis;
• NICU admission for more than 24 hours;
• hypoglycemia requiring care;
• thrombocytopenia;
• transient tachypnea of the newborn;
• hyperbilirubinemia; and
• 5-minute Apgar score of less than 7.

Secondary outcomes included birth weight, birth weight percentile of 10% or less, cesarean delivery and operative vaginal delivery.

Overall, 181 pregnancies were used as references, 81 had resolved FGR and 97 had persistent FGR. Pregnancies with resolved FGR (OR = 1.9; 95% CI, 1.1-3.5; P = .026) and pregnancies with persistent FGR (OR = 2.8; 95% CI, 1.7-4.9; P < .001) experienced the primary outcome more frequently compared with the reference group. This was especially true for hypoglycemia requiring care (resolved FGR, 21%; persistent FGR, 21.6% vs. no FGR, 8.8%) and NICU admission for more than 24 hours (resolved FGR, 14.8%; persistent FGR, 19.6% vs. no FGR, 8.3%).

When adjusting for oligohydramnios, chronic hypertension, opioid use disorder and maternal age, researchers observed persistent findings for pregnancies with resolved FGR (adjusted OR = 2.04; 95% CI, 1.11-3.74; P = .022) and pregnancies with persistent FGR (aOR = 2.83; 95% CI, 1.58-5.07; P < .001).

In addition, more pregnancies with resolved FGR and pregnancies with persistent FGR had lower mean birth weight (2,945 g and 2,538 g, respectively vs. no FGR, 3,481 g) and a higher percentage of these pregnancies had a birth weight percentile of 10% or less (21% and 47.4%, respectively vs. no FGR, 3.9%), but similar rates of cesarean section and operative vaginal delivery.

“Larger studies are warranted to assess the interval and duration of antepartum fetal surveillance as well as the role of umbilical artery Doppler velocimetry in stratifying risk in the resolved FGR population,” the researchers wrote.