Cardiac function in newborns of obese women and the effect of exercise during pregnancy. A randomized controlled trial

Abstract

Background: The prevalence of maternal obesity is rising. Pre-pregnancy obesity is associated with later cardiovascular disease in the child and the underlying pathogenesis begins in early life. Therefore, pregnancy and infancy are key periods for potential intervention. The aim of this study was to study the cardiac function in newborns of obese women compared to newborns of normal-weight women, and to determine if exercise intervention during pregnancy could have an effect on cardiac function of newborns to obese women.

Material and methods: Fifty-five pregnant women, 51 obese (BMI ≥ 30 kg/m2) and four overweight (BMI 28-30 kg/m2), were randomized to an exercise training group (n = 27) or a control group (standard maternity care, n = 28). From gestational week 14 until delivery participants in the intervention group were offered supervised training sessions three times weekly. In addition, they were told to exercise at home once weekly. All newborns had an echocardiogram performed 1-3 days and 6-8 weeks after delivery. The results were compared with newborns of normal weight women (n = 20, standard maternity care).

Results: Newborns of obese women had an impaired systolic and diastolic cardiac function with reduced global strain, strain rate, tissue Doppler velocities and a thicker intraventricular septum at birth and after 6-8 weeks after delivery compared to newborns of normal weight women. Exercise had no statistically significant effect on either of the cardiac function parameters. The mean (± standard deviation) adherence to the exercise protocol was 1.3 ± 0.8 sessions per week for supervised training and 0.8 ± 0.7 sessions per week for home-based exercise training.

Conclusions: Newborns of obese women had reduced cardiac function and thicker intraventricular septum compared to newborns of normal weight women. Exercise training during pregnancy had no significant effect, potentially due to a low number of subjects and low adherence to the exercise protocol.

Trial registration: ClinicalTrials.gov NCT01243554.

Fig 1. Flowchart of the pregnant women in the NeoETIP trial (CONSORT flow diagram).

Women who were lost to follow-up throughout the pregnancy- and delivery period, categorized in the “other reasons”- group, either forgot or chose not to give notice of birth to the study group regarding the scheduled cardiac examination of the newborn. Neonates in the Exercise Training in Pregnancy (NeoETIP), Body mass index (BMI), Number (N).

Fig 2. Flowchart of the newborns in the NeoETIP trial (CONSORT flow diagram).

The final study population: Newborns of normal weight women (NNW), Newborns of obese women (NOW), NOWe randomized to exercise and NOWc randomized to control (standard maternity care). The newborns underwent cardiac examination 1–3 days of age and 6–8 weeks of age. Neonates in the Exercise Training in Pregnancy (NeoETIP), Body mass index (BMI), Number (N).

Fig 3. Cardiac function–Longitudinal strain in the left ventricle.

Examples of apical 4 chamber views with speckle tracking in a newborn of a normal weight women (NNW, the upper image) and a newborn of an obese women in the control group (NOWc, lower image) at 6–8 weeks.

Fig 4. Cardiac function–A comparison between groups over time.

The figure demonstrates the difference between the groups with 95% confidence intervals and the physiologic increase in cardiac function over time during the first weeks of life. The symbols represent the following groups: The filled circle (●) represents newborns of normal weight women (NNW), and a dotted line is drawn between the circles. The triangle (Δ) represents newborns of obese women in the exercise group (NOWe), and a solid line is drawn between the triangles. The square (□) represents newborns of obese women in the control group (NOWc), and a broken line is drawn between the squares. Left ventricle (LV), Right ventricle (RV), S’ peak systolic tissue Doppler velocity (TDV), E’ peak early diastolic TDV, mitral annular-plane systolic excursion (MAPSE), tricuspid annular-plane systolic excursion (TAPSE).