(695) Maternal height and risk of neonatal morbidity in pregnancies complicated by fetal growth restriction

To evaluate the role of maternal height in differentiating constitutionally small infants from pathologically growth-restricted infants who have not met their genetic growth potential by assessing risk of neonatal morbidity.

Study Design:

Pregnancies complicated by fetal growth restriction (FGR) were identified within a large, NIH-funded database of pregnancies resulting in delivery of live, singleton, non-anomalous infants at a single center 2002-2013. Neonatal morbidity was defined as one or more of the following: 5-minute Apgar < 7, arterial cord pH < 7.0, sepsis, neonatal death, or need for respiratory support, chest compressions, phototherapy, exchange transfusion, or hypoglycemia treatment. Maternal heights were compared between infants who experienced neonatal morbidity and those who did not, using raw height and the ratio of maternal height to infant birth weight. 

Results:

Neonatal morbidity occurred in 174 of 575 eligible pregnancies (30%) and was associated with greater maternal height (160 vs 159cm, p = 0.03) and greater ratio of maternal height to infant birth weight (77 vs 66, p < 0.01) – an infant of a given birth weight was more likely to experience neonatal morbidity if delivered to a tall mother. Unadjusted odds ratio was 1.06 (95% confidence interval 1.04-1.08). Area under the received operating characteristic curve was 0.71 (Figure). This remained statistically significant after adjusting for umbilical artery Doppler findings, age, and insurance status (aOR 1.06, 95% CI 1.04-1.08, p < 0.01). There were no statistically significant differences in gestational age at delivery, ultrasound estimated fetal weight centile, or rates of diabetes, hypertension, renal disease, cardiac disease, smoking, or illicit substance use.

Conclusion:

Among pregnancies complicated by fetal growth restriction, neonatal morbidity occurred more frequently among infants delivered to taller mothers and in cases of a higher ratio of maternal height to infant birth weight. However, the effect size is modest and further study is needed.

The views expressed in this article are those of the authors and do not necessarily reflect the official policy or position of the Department of the Navy, Department of Defense, or the United States Government. CD and ML are military service members, who contributed to this work as part of their official duties. Their contributions are inseparable from the contribution of ME. Title 17 U.S.C. 105 provides that “Copyright protection under this title is not available for any work of the United States Government,” which includes work prepared by a military service member or employee of the United States Government as part of that person’s official duties. Research data derived from an approved Care New England - Women & Infants IRB protocol.