Timing of delivery and neonatal outcomes for small-for-gestational-age fetuses

Objectives: To investigate whether antenatal recognition of small-for-gestational-age (SGA) fetuses with normal maternal and fetal Doppler values delivered after 34 weeks' gestation is associated with changes in the risk of adverse maternal and neonatal outcomes.

Methods: In this retrospective study, we included 313 singleton SGA fetuses and 313 appropriate-for-gestational-age control fetuses born between 34 and 42 weeks' gestation from 2009 to 2012. Small-for-gestational-age fetuses identified before delivery (n = 124), for whom antenatal surveillance was performed until delivery (estimated fetal weight twice weekly and Doppler evaluation of the fetal compartment once weekly), were compared to those not identified at delivery (n = 189). The latter group did not undergo antenatal surveillance for several reasons (women for whom a sonographic evaluation or gynecologic consultation was not performed in the third trimester and incorrect sonographic biometric evaluation in the third trimester). Main outcome measures were mode of delivery, perinatal complications, and neonatal intensive care unit admission. The risk of serious fetal complications was assessed by cross-tabulation analysis adjusted for gestational age and degree of SGA.

Results: Prenatally recognized SGA fetuses were smaller and delivered earlier than unrecognized SGA fetuses (P< .05). Fetal acidemia (pH <7.10) was significantly more common in unrecognized SGA fetuses (3.7% versus 0%). Small-for-gestational-age fetuses at or below the 3rd percentile were more commonly recognized prenatally and hospitalized in the neonatal intensive care unit. Unrecognized SGA fetuses also had worse fetal outcomes compared to controls (P< .05). Recognized and unrecognized SGA fetuses were born significantly more frequently by cesarean delivery (P < .05). No significant differences in perinatal outcomes were found between recognized SGA deliveries with or without medical induction.

Conclusions: Antenatal recognition of SGA fetuses delivered after 34 weeks' gestation might improve perinatal outcomes. Medical induction of labor did not modify neonatal outcomes among prenatally recognized SGA fetuses.