Association of third-trimester abdominal circumference with provider-initiated preterm delivery

• Published in: The journal of maternal-fetal & neonatal medicine Vol. 27; no. 12; pp. 1228 - 1231
• Main Authors: Hawkins, Leah K., Schnettler, William T., Modest, Anna M., Hacker, Michele R., Rodriguez, Diana
• Format: Journal Article
• Language: English
• Published: England Informa UK Ltd 01-08-2014; Taylor & Francis
• Subjects: Abdomen - anatomy & histology; Abdominal circumference; Adult; Decision Making; Delivery, Obstetric - methods; Delivery, Obstetric - statistics & numerical data; Female; Fetal Growth Retardation - diagnosis; Fetal Growth Retardation - epidemiology; Fetal Growth Retardation - therapy; fetal surveillance; Fetal Weight; Health Personnel; Humans; Infant, Newborn; Infant, Small for Gestational Age; obstetrics; Pregnancy; Pregnancy Outcome - epidemiology; Pregnancy Trimester, Third; Premature Birth - epidemiology; preterm delivery; Retrospective Studies; Sagittal Abdominal Diameter; third-trimester ultrasound; Waist Circumference; Abdominal circumference; obstetrics; fetal surveillance; third-trimester ultrasound; preterm delivery
• ISSN: 1476-7058; 1476-4954
• DOI: 10.3109/14767058.2013.852171

Abstract
Objective: Evaluate the association of a small third-trimester abdominal circumference (AC < 10th percentile) in the setting of a normal estimated fetal weight (EFW 10th percentile) with gestational age at delivery, indication for delivery and neonatal outcomes.
Methods: Retrospective cohort study at an academic hospital of women with singleton pregnancy seen for ultrasound from 28+0-33+6 weeks of gestation during 2009-2011. Outcomes were compared between two groups: normal AC (AC and EFW 10th percentile) and small AC (AC < 10th percentile and EFW 10th percentile).
Results: Among 592 pregnancies, fetuses in the small AC group (n = 55) experienced a higher incidence of overall preterm delivery (RR: 2.2, 95% CI: 1.3-3.7) and provider-initiated preterm delivery (RR: 3.7, CI: 1.8-7.5) compared to those in the normal AC group (n = 537). Neonates in the small AC group had a lower median birth weight whether delivered at term (p < 0.001) or preterm (p = 0.04), but were not more likely to experience intensive care unit admission or respiratory distress syndrome (all p   0.35).
Conclusions: Small AC, even in the setting of an EFW 10th percentile, was associated with a higher incidence of overall and provider-initiated preterm delivery despite similar neonatal outcomes. Further investigation is warranted to determine whether these preterm deliveries could be prevented.