Introduction
Abnormal placental morphology and blood flow is associated with pregnancy-related complications and poor perinatal outcomes. The acute haemodynamic changes which occur during an exercise bout act as a stimulus for beneficial vascular adaptations. However, the effect of regular physical activity (PA) and conversely the impact of sedentary behaviour (SB) on placental morphology and vascular function is less clear. This study investigated maternal PA and SB and examined the association of these activities with placental growth and function during gestation and at delivery.
Methods
This study included women recruited from the Queensland Family Cohort study (n=358). Women reported PA behaviours at 24-, 28- and 36-weeks of gestation using a modified Active Australia Survey and were categorised into groups of no activity, low, moderate, and high volume. Participants reported average daily sitting time, whereby SB was considered as ≥8 hours of sitting/day. Placental stiffness and thickness and uterine and umbilical cord arterial resistance were measured through ultrasound at each timepoint, and placental dimensions were measured following delivery. Multivariate regression was used to investigate the associations between PA volume or SB on these placental outcomes.
Results
Engaging in any volume of PA during pregnancy did not affect any placental measures during gestation or at delivery. However, SB at 36-weeks was positively associated with placental stiffness (p=0.025), and negatively associated with thickness (p=0.044) and the umbilical artery pulsatility index (p=0.014). Further, SB was associated with altered morphology at term, demonstrated by a negative correlation with placental weight (p=0.002), depth (p=0.009) and surface area (p=0.043).
Conclusion
PA at any volume during the second half of pregnancy is not associated with significant changes to placental morphology. Although, SB during the antenatal period may be an independent risk to reduced placental growth and development which could result in adverse outcomes for the fetus in complicated pregnancies.