Abstract
Objective This study aimed to evaluate whether transient fetal growth restriction (FGR) that
resolves prior to delivery confers a similar risk of neonatal morbidity as uncomplicated
FGR that persists at term.
Study Design This is a secondary analysis of a medical record abstraction study of singleton live-born
pregnancies delivered at a tertiary care center between 2002 and 2013. Patients with
fetuses that had either persistent or transient FGR and delivered at 38 weeks or later
were included. Patients with abnormal umbilical artery Doppler studies were excluded.
Persistent FGR was defined as estimated fetal weight (EFW) <10th percentile by gestational
age from diagnosis through delivery. Transient FGR was defined as EFW <10th percentile
on at least one ultrasound, but not on the last ultrasound prior to delivery. The
primary outcome was a composite of neonatal morbidity: neonatal intensive care unit
admission, Apgar's score <7 at 5 minutes, neonatal resuscitation, arterial cord pH
<7.1, respiratory distress syndrome, transient tachypnea of the newborn, hypoglycemia,
sepsis, or death. Baseline characteristics and obstetric and neonatal outcomes were
compared using Wilcoxon's rank-sum and Fisher's exact test. Log binomial regression
was used to adjust for confounders.
Results Of 777 patients studied, 686 (88%) had persistent FGR and 91 (12%) had transient
FGR. Patients with transient FGR were more likely to have a higher body mass index,
gestational diabetes, diagnosed with FGR earlier in pregnancy, have spontaneous labor,
and deliver at later gestational ages. There was no difference in the composite neonatal
outcome (relative risk = 1.03, 95% confidence interval [CI] 0.72, 1.47) for transient
versus persistent FGR after adjusting for confounders (adjusted relative risk = 0.79,
95% CI 0.54, 1.17). There were no differences in cesarean delivery or delivery complications
between groups.
Conclusion Neonates born at term after transient FGR do not appear to have differences in composite
morbidity compared with those where uncomplicated FGR persists at term.
Key Points
-
No differences in neonatal outcomes in uncomplicated persistent versus transient FGR
at term.
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Transient FGR pregnancies more likely to deliver at later gestational ages.
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No differences in mode of delivery or obstetric complications in persistent versus
transient FGR at term.
Keywords
fetal growth restriction - antepartum surveillance - neonatal outcomes - small for
gestational age - composite neonatal morbidity
