Fetal and maternal Doppler adaptation to maternal exercise during pregnancy: a randomized controlled trial

Abstract

Background

Regular and supervised exercise during pregnancy is worldwide recommended due to its proven benefits, but, during exercise, maternal blood flow is redirected from the viscera to the muscles and how fetal wellbeing may be affected by this redistribution is still not well known.

Objective

To analyze the longitudinal effect of a supervised moderate physical exercise program during pregnancy on uteroplacental and fetal Doppler parameters.

Methods

This is a planned secondary analysis of an randomized controlled trial (RCT), performed at Hospital Universitario de Torrejón, Madrid, Spain, including 124 women randomized from 12⁺⁰ to 15⁺⁶ weeks of gestation to exercise vs. control group. Fetal umbilical artery (UA), middle cerebral artery, and uterine artery pulsatility index (PI), were longitudinally collected by Doppler ultrasound assessment throughout gestation, and derived cerebroplacental ratio (normalized by z-score), and maternal mean PI in the uterine arteries (normalized by multiplies of the median). Obstetric appointments were scheduled at 12 (baseline, 12⁺⁰ to 13⁺⁵), 20 (19⁺⁰ to 24⁺²), 28 (26⁺³ to 31⁺³) and 35 weeks (32⁺⁶ to 38⁺⁶) of gestation. Generalized estimating equations were adjusted to assess longitudinal changes in the Doppler measurements according to the randomization group.

Results

No significant differences in the fetal or maternal Doppler measurements were found at any of the different checkup time points studied. The only variable that consistently affected the Doppler standardized values was gestational age at the time of assessment. The evolution of the UA PI z-score during the pregnancy was different in the two study groups, with a higher z-score in the exercise group at 20 weeks and a subsequent decrease until delivery while in the control group it remained stable at around zero.

Conclusions

A regular supervised moderate exercise program during pregnancy does not deteriorate fetal or maternal ultrasound Doppler parameters along the pregnancy, suggesting that the fetal well-being is not compromised by the exercise intervention. Fetal UA PI z-score decreases during pregnancy to lower levels in the exercise group compared with the control group.

Keywords:

• Exercise
• pregnancy
• Doppler
• fetal wellbeing
• physical activity

Acknowledgements

The authors thank the women who participate in the study and the Obstetrics Team at Hospital Universitario de Torrejón for their collaboration in the project. We also acknowledge Hospital Universitario de Torrejón, Universidad Politécnica de Madrid, Sanitas Healthcare and the iMaterna Foundation for the financial support.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This research was funded by Research Grants provided by Hospital Universitario de Torrejón (Madrid, Spain), Universidad Politécnica de Madrid (Madrid, Spain), Sanitas Healthcare and iMaterna Foundation (www.imaterna.org).