Background/Aims: Maternal changes in diet quality and physical activity (PA) throughout pregnancy are unclear. This study described the changes in diet quality and PA (i.e., trajectories) during pregnancy and examined their associations with maternal characteristics and gestational weight gain (GWG).
Method: Dietary intake and PA were collected through surveys at 18-, 28-, and 36-week gestation among pregnant women (n=688) recruited from three health sectors in New South Wales. Diet quality was assessed by Dietary Guideline Index (DGI) with higher score representing greater adherence. Multi-trajectory modelling identified joint trajectories of DGI and PA. Multivariable logistic regression assessed maternal determinants of DGI and PA trajectories and their association with GWG.
Results: Most women (58.0%) exhibited a “high-stable DGI low-stable PA” trajectory, 34.5% followed the “low-increasing DGI low-stable PA” trajectory, and 7.5% of the women had a “mid-stable DGI high-decreasing PA” trajectory. Higher maternal age (OR 1.07, 95%CI 1.04, 1.11), being married (OR 3.26, 95%CI 1.66, 6.42) and the diagnosis of gestational diabetes (OR 2.79, 95%CI 1.55,5.03) were associated with higher odds of being in the “high-stable DGI low-stable PA” than the “low-increasing DGI low-stable PA” trajectory. Women who were not working (OR 0.56, 95%CI 0.36, 0.86), identified as Aboriginal or Torres Strait Islander (OR 0.48, 95%CI 0.25, 0.94) and with high school (OR 0.27, 95%CI 0.18, 0.43) or certificate/diploma education (OR 0.50, 95% 0.34, 0.74) showed a lower likelihood of following the “high-stable DGI low-stable PA” trajectory. Maternal age, working status, education and gestational diabetes were also associated with the “mid-stable DGI high-decreasing PA” trajectory. No evidence of an association was found between DGI and PA trajectories and GWG.
Conclusions: Three heterogeneous joint-trajectories of DGI and PA were identified during pregnancy. Maternal age, marital status, gestational diabetes, education level and working status were identified as significant determinants of DGI and PA trajectories.