Cause-Specific Stillbirth and Neonatal Death According to Prepregnancy Obesity and Early Gestational Weight Gain: A Study in the Danish National Birth Cohort.

Ellen Aagaard Nohr,Bodil Hammer Bech,Helene Kirkegaard,Sanne Wolff,Chunsen Wu,Jørn Olsen,Anne-Marie Nybo Andersen

doi:10.3390/nu13051676

Abstract

Maternal obesity is associated with impaired fetal and neonatal survival, but underlying mechanisms are poorly understood. We examined how prepregnancy BMI and early gestational weight gain (GWG) were associated with cause-specific stillbirth and neonatal death. In 85,822 pregnancies in the Danish National Birth Cohort (1996–2002), we identified causes of death from medical records for 272 late stillbirths and 228 neonatal deaths. Prepregnancy BMI and early GWG derived from an early pregnancy interview and Cox regression were used to estimate associations with stillbirth or neonatal death as a combined outcome and nine specific cause-of-death categories. Compared to women with normal weight, risk of stillbirth or neonatal death was increased by 66% with overweight and 78% with obesity. Especially deaths due to placental dysfunction, umbilical cord complications, intrapartum events, and infections were increased in women with obesity. More stillbirths and neonatal deaths were observed in women with BMI < 25 and low GWG. Additionally, unexplained intrauterine death was increased with low GWG, while more early stillbirths were seen with both low and high GWG. In conclusion, causes of death that relate to vascular and metabolic disturbances were increased in women with obesity. Low early GWG in women of normal weight deserves more clinical attention.

Highlights

Among adverse outcomes related to maternal obesity, the increased risk of losing a child, whether it is in late pregnancy or shortly after birth, is probably the most devastating and tragic event
While it is well-established that especially post-term pregnancies in women with obesity are at higher risk of antepartum intrauterine death [2,3], the evidence about other causes or subtypes of stillbirth or neonatal death associated with maternal obesity is less consistent
Unexplained intrauterine death (UID) was only possible for stillbirths, just as the category “preterm birth” could only include neonatal deaths

Summary

Introduction

Among adverse outcomes related to maternal obesity, the increased risk of losing a child, whether it is in late pregnancy or shortly after birth, is probably the most devastating and tragic event. A plenitude of studies contribute to the evidence on impaired survival in the offspring of mothers with obesity, both in late pregnancy and during the first month of life [1], but the underlying mechanisms are still poorly understood. While it is well-established that especially post-term pregnancies in women with obesity are at higher risk of antepartum intrauterine death [2,3], the evidence about other causes or subtypes of stillbirth or neonatal death associated with maternal obesity is less consistent. In contemporary data from Sweden, neonatal deaths from birth asphyxia and other neonatal morbidities were associated with maternal obesity [6]

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