Abstract
Objective There is wide variation in the management of pregnancies complicated by abnormal
placental cord insertion (PCI), which includes velamentous cord insertion (VCI) and
marginal cord insertion (MCI). We tested the hypothesis that abnormal PCI is associated
with small for gestational age (SGA) infants.
Study Design This is a retrospective cohort study of all pregnant patients undergoing anatomic
ultrasound at a single institution from 2010 to 2017. Patients with abnormal PCI were
matched in a 1:2 ratio by race, parity, gestational age at the time of ultrasound,
and obesity to patients with normal PCIs. The primary outcome was SGA at delivery.
Secondary outcomes were cesarean delivery, preterm delivery, cesarean delivery for
nonreassuring fetal status, 5-minute Apgar score < 7, umbilical artery pH < 7.1, and
neonatal intensive care unit admission. These outcomes were compared using univariate
and bivariate analyses.
Results Abnormal PCI was associated with an increased risk of SGA (relative risk [RR]: 2.43;
95% confidence interval [CI]: 1.26–4.69), increased risk of preterm delivery <37 weeks
(RR: 3.60; 95% CI: 1.74–7.46), and <34 weeks (RR: 3.50; 95% CI: 1.05–11.63) compared
with patients with normal PCI. There was no difference in rates of cesarean delivery,
Apgar score of <7 at 5 minutes, acidemia, or neonatal intensive care unit admission
between normal and abnormal PCI groups. In a stratified analysis, the association
between abnormal PCI and SGA did not differ by the type of abnormal PCI (p for interaction = 0.46).
Conclusion Abnormal PCI is associated with an increased risk of SGA and preterm delivery. These
results suggest that serial fetal growth assessments in this population may be warranted.
Key Points
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Abnormal PCI is associated with SGA infants and preterm birth.
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If an abnormal PCI is identified, the provider should consider serial growth ultrasounds.
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There is no difference in obstetric outcomes between VCI and MCI.
Keywords
placental cord insertion - small for gestational age - velamentous cord insertion
- marginal cord insertion - preterm delivery - ultrasound - anatomic survey
