The Relationship of Objectively Measured Physical Activity and Sedentary Behaviour with Gestational Weight Gain and Birth Weight

Objective. To evaluate the relationship of physical activity (PA) and sedentary behaviour with gestational weight gain (GWG) and birth weight. Design. Combined data from two prospective studies: (1) nulliparous pregnant women without BMI restrictions and (2) overweight and obese pregnant women at risk for gestational diabetes. Methods. Daily PA and sedentary behaviour were measured with an accelerometer around 15 and at 32–35 weeks of gestation. The association between time spent in moderate-to-vigorous PA (MVPA) and in sedentary activities with GWG and birth weight was determined. Main outcome measures were GWG between 15 and 32 weeks of gestation, average GWG per week, and birth weight. Results. We studied 111 women. Early in pregnancy, 32% of women spent ≥30 minutes/day in at least moderate PA versus 12% in late pregnancy. No significant associations were found between time spent in MVPA or sedentary behaviour with GWG or birth weight. Conclusions. We found no relation between MVPA and sedentary behaviour with GWG or birth weight. The small percentage of women meeting the recommended levels of PA indicates the need to inform and support pregnant women to maintain regular PA, as there seems to be no adverse effect on birth weight and maintaining PA increases overall health. 1. Introduction Excessive weight gain during pregnancy is associated with an increased risk of obstetrical, maternal, and fetal complications [1–4] and postpartum weight retention [5]. It increases the risk of obesity in children [5–7]. This contributes to the prevalence of women who are overweight or obese and increases the long-term risk of body weight-associated diseases, which impose a great pressure on health care [5, 8–12]. The American Institute of Medicine (IOM) updated their evidence-based guidelines for weight development during pregnancy in 2009 [13]. However, 53% of all women gain more weight than advised by the IOM. This is even more pronounced in women with overweight or obesity, with 68.9% and 59.8%, respectively, exceeding the recommendations [14]. Many trials have been conducted evaluating the effect of different lifestyle interventions on gestational weight gain (GWG) and adverse pregnancy outcomes, which were recently reviewed and combined in a meta-analysis [15, 16]. Combining results of 15 interventions consisting of physical activity (PA) alone did not result in a statistically significant effect on GWG and showed a very small but statistically significant reduction in mean birth weight. However, it must be noted that the compliance with the interventions was