The acceptance rate of two exercise programs during pregnancy and their effect on some maternal, fetal, and neonatal outcomes

Abstract

Introduction: Despite the known benefits of physical activity and exercise during pregnancy, few pregnant women regularly exercise. Most studies on exercise have focused on supervised exercise, and there is limited evidence on adherence to and the effect of other exercise programs on pregnancy outcomes. This study thus aimed to determine the acceptance rate of two exercise programs during pregnancy (exercise with adjusted supervision and home workout) and their effect on the mean depression and positive and negative affect scores during pregnancy and after delivery, as well as the infant's birth weight (primary outcomes).

Method: In this three-arm parallel controlled randomized clinical trial, 150 eligible pregnant women with a gestational age of 12-18 weeks in Mahabad (Iran) were conveniently selected and allocated to three groups (supervised exercise, home workout, and control). The allocation sequence was determined by a person not involved in sampling and data collection via stratified (primiparous and multiparous) randomized block design, with centralized allocation concealment. Blinding was not possible due to the nature of the study.

In the first experimental group (supervised exercise), based on a schedule set with them, the women participated in three exercise sessions per week (including a face-to-face session which was held one-on-one or in groups of up to four) from the time they were enrolled in the study until the 38th week of pregnancy. For the second experimental group, in weeks 12-18 and 26-28 of pregnancy, an aerobic exercise training session suitable to their gestational age was held practically (face-to-face one-on-one session or in groups of up to four). After delivering the educational video and providing explanations, both experimental groups were asked to exercise at home or walk while watching the video, based on the defined program. The control group did not receive any intervention.

The women's physical activity was measured via the Pregnancy Physical Activity Questionnaire (PPAQ) at the baseline; depression was assessed via the Edinburgh Postnatal Depression Scale (EPDS) on weeks 26-28 of pregnancy and six weeks post-delivery; and the positive and negative affect was measured via the Positive and Negative Affect Schedule (PANAS) in weeks 26-28 and 36-38 of pregnancy and six weeks post-delivery (in addition to the baseline).

An analysis of covariance (ANCOVA) was run to compare groups in terms of the mean quantitative outcomes with a normal distribution (by controlling the effect of the stratification factor). The Kruskal-Wallis test was performed to compare the mean rank scores of quantitative outcomes with a non-normal distribution. The Mann-Whitney U test was run for the pairwise comparison of the group.

Results: Out of 50 people allocated to each group of supervised exercise, home workout, and control, respectively 47, 46, and 49 women were followed-up in weeks 26-28 of pregnancy; 45, 47, and 47 women in weeks 36-38 of pregnancy; and 45, 47, and 46 people six weeks post-delivery. There was no significant difference among the groups in terms of baseline characteristics. About two-thirds (65%) of the women were primiparous, and 87% were homemakers. The mean (SD) of their age was 27.0 years and that of their body mass index (BMI) was 26.0. The median of their physical activity was 124 MET hours per week at the baseline (25th percentile is 86, 75th percentile is 152).

In the supervised exercise group, of the 29 exercise sessions, 13 women (26%) attended at least 70% of the sessions, and 19 women (38%) attended 50-70% of the sessions. In the Home base group, 42 women (84%) participated in both training sessions. In the supervised exercise group, 32% of women in weeks 20-27 of pregnancy and 42% in weeks 28-35 of pregnancy, and in the Home base group, 44-52% of the women in weeks 20-35 of pregnancy performed total exercise (aerobics and walking) of less than 150 minutes per week. The mean rank of the overall exercise in weeks 20-27 was significantly more in the supervised exercise than the Home base group. The median duration of aerobics in the supervised exercise group was 90 minutes per week in weeks 20-31 of pregnancy, and it decreased to 60 minutes per week in weeks 32-40; in the Home base group, this value was 55 minutes per week in weeks 20-23 and then decreased, such that more than half of the women in this group did not perform this exercise from week 32 of pregnancy onwards.

There was no significant difference between the groups in terms of the scores of depression during pregnancy, positive and negative affect during pregnancy and post-delivery, and the infant's birth weight. However, six weeks post-delivery, the depression score was significantly lower in the supervised exercise than the control group (mean difference -9.1, 95% CI: -4 to -0.1, P=0.018).

Conclusion: In both experimental groups, the degree of adherence to the exercise programs, especially home workout, was relatively low, and the frequency of not exercising for the minimum time recommended (150 minutes per week) was high in both groups, especially the Home base group. These results highlight the need to hold more supervised exercise sessions. Exercise programs with adjusted supervision only had a positive effect on reducing the postpartum depression score, while the home workout program did not have a significant positive effect on any of the examined primary outcomes.