Year

2016

Degree Name

Doctor of Philosophy in Health Sciences

Abstract

The Australian physical activity guidelines recommend that pregnant women without exercise contraindication or medical complications can safely continue to participate in physical activity. Participation in physical activity during pregnancy may have possible health benefits such as ease of delivery, reducing birth complications and developing a risk of gestational diabetes. These likely benefits are demonstrated in the Australian recommendation which indicated that women in pregnancy should involve in 30 minutes a day or more of moderate exercise for 3 days or most of the week days.

Despite these recommendations, little is known about patterns of physical activity among Australian pregnant women. The purpose of this research was to evaluate the level of self-reported physical activity in Australian pregnant women when compared with the recommended National Physical Activity Guidelines for Australians and temporal changes in physical activity before, during and after pregnancy. Also determine the perceived barriers and benefits for pregnant women and examined the association between physical activity prior to and during pregnancy and birth outcomes. The research was conducted at Randwick hospital, Sydney and Wollongong hospital, Wollongong, NSW Australia. Data from volunteer women were collected using two modified validated questionnaires, Pregnancy Physical Activity Questionnaire and Active Australia Survey (n = 740).

The main study examined the level of physical activity among pregnant women by evaluating frequency, duration and intensity of various common maternal activities. Results using the Pregnancy Physical Activity Questionnaire demonstrated a significant reduction in the total weekly energy expenditure (MET-h.wk-1) from prior pregnancy 33.5 (SD 10.6) to approximately 25.7 ±8.3 and 25.1 (SD 7.7) in 1st and 2nd trimesters and continued decreasing in the 3rd trimester and after birth 23.3, 21.7 (SD 6.6, 8.3). Results also confirmed that there was a significant change in physical activity levels across the five different time periods of the study. The study findings indicated that occupational energy expenditure was the highest in prior to pregnancy and also it was the largest contribution to energy expenditure 22.8 ± 19.7 MET-h.wk-1. Whereas exercise energy expenditure was the lowest and recorded the least contribution to energy expenditure with mean of 1.2 ±0.1 MET-h.wk-1. Results using the Active Australia Survey showed a significant reduction in the mean weekly energy expenditure (MET-h.wk-1) prior pregnancy (13.8 ±8.1) and trimester 1 (8.1 ±9.0), trimester 2 (9.5 ±8.4), trimester 3 (7.1 ±5.7) and after pregnancy (7.1 ±8.2) where decrease in energy expenditure were occurred. Based on type of activity, pregnant women reported the highest mean level of energy expenditure in walking quickly which was approximately identical among participants prior to pregnancy and after birth (24.4 MET-h.wk-1). Pregnant women spent the least energy expenditure (0.8 MET- xv h.wk-1) in strong leisure activity. The study also observed that Australian pregnant women did not meet the minimum Australian physical activity guidelines (≥ 10 MET-h.wk).

Women participated mostly in light to moderate physical activity. Light intensity was prior pregnancy (12.8 METs-h.wk-1), 1st trimester (9.9 METs-h.wk-1), 2nd trimester (10.5 METs-h.wk-1), 3rd trimester (11.3 METs-h.wk-1) and postpartum (12.8 METs-h.wk-1), while moderate intensity was unchanged during trimesters compared with prior and post pregnancy. Participation in vigorous intensity physical activity was the lowest and quite steady across the 1st and 2nd trimesters (0.94, 0.99 METs-h.wk-1) and was more limited in the 3rd trimester (0.57 METs-h.wk-1).

The birth outcomes variables was analysed separately against mean total physical activity among active women who met the physical activity guidelines (>10 MET-h.wk) before and during pregnancy. The Pregnancy Physical Activity Questionnaire indicated that physical activity prior to and during in 1st and 2nd trimesters was not associated with normal birth, decreased risk of Caesarean Section, time baby spend in intensive unit care and baby’s physical condition. Physical activity during the 2nd and 3rd trimesters was significantly associated with Apgar scores and gestational age at birth. Data using Active Australia Survey showed a significant correlation between physical activity prior to pregnancy and in the 2nd with birth weight and time spent in the neonatal care. No relationship between physical activity energy expenditure and other related birth outcomes such as maternal age, Apgar scores and gestational diabetes. Despite the few association between physical activity and birth outcomes which was found, strong support for increased the effect of physical activity prior to and during pregnancy on birth outcomes was not significantly found in most of the birth outcomes variables. Further investigation indicated there was no correlation between having level of education and participation level of physical activity before, during and after pregnancy.

Pregnant women visit their health care provider on a regular basis right through pregnancy. The research suggests that this may be the right place where essential information on the barriers to and benefits of physical activity during pregnancy can be provided. Women identified a number of barriers for being physically inactive; responses indicated the most commonly perceived barrier to physical activity was personal difficulties and lack of time. Mean scores for selected barriers were between 2.0 and 2.8, which equated between disagree and strongly disagree on the exercise barriers and benefit scoring scale. Approximately most of the pregnant women (60%) in the current investigation believed there were several advantages for participation in exercise. Most women in pre pregnancy, during 1st , 2nd , 3rd trimesters and postpartum xvi reported that participating in physical activity would improve their physical development and feeling better as the most leading benefits of exercise. Mean scores for the most important benefits were ranged between 2.3 and 3.6 which associated between agree and disagree on the exercise barriers and benefit scoring scale.

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Unless otherwise indicated, the views expressed in this thesis are those of the author and do not necessarily represent the views of the University of Wollongong.