Pregnancy outcome after false diagnosis of fetal growth restriction

To evaluate pregnancy outcome following false diagnosis of fetal growth restriction (FGR).

Retrospective analysis of all singleton term deliveries of appropriately grown fetuses (10-90th weight percentiles) in a single medical center (2007-2014). Elective cesarean-section, diabetes, and hypertension were excluded. Cohort was stratified based on third trimester sonographic estimated-fetal-weight (≥32 weeks). Women with false diagnosis FGR (<10th percentile) were compared with the rest (control). Induction of labor, cesarean deliveries, and short-term perinatal outcome were compared. Logistic regression analysis was performed to adjust outcome for birth weight and gestational age at delivery.

Of 34,474 pregnancies, 415 were falsely diagnosed as FGR (1.2%). Women in study group delivered earlier (38.6 ± 1.1 versus. 39.0 ± 0.9) with lower birth weights (2856 ± 270 versus 3271 ± 307 grams) and increased rate of labor inductions (19.8% versus 6.4%) and cesarean deliveries (10.8% versus 5.7%). Despite appropriate birth weight, study group neonates had higher rates of NICU admissions (10.6% versus 6.8%), mechanical ventilation (1.7% versus 0.5%), transient tachypnea of the newborn (1.7% versus 0.5%), hypoglycemia (1.7% versus 0.5%), and jaundice (11.3% versus 7.0%). p < 0.01 for all. All remained significant after adjustment to confounders.

False diagnosis of FGR is associated with higher rates of induction of labor, cesarean deliveries, and short-term adverse neonatal outcome.