Effects of Physical Activity on Preterm Birth

Abstract

The authors conducted a cohort study of low income women to determine the effect of physical activity on the risk of preterm birth. Women were sampled prenatally from four clinic sites and were scheduled for delivery at the University of Maryland Medical Systems (UMMS). Women who delivered infants at UMMS but who had received no prenatal care were also eligible. Preterm delivery was defined as a delivery prior to 37 completed weeks gestation. After adjusting for confounders, the odds of preterm delivery were increased for women who climbed stairs > or = 10 times per day (odds ratio (OR) = 1.60, 95% confidence interval 1.05-2.46) and for women who engaged in purposive walking > or = 4 days per week (OR = 2.10, 95% CI 1.38-3.20). Leisure-time exercise (> or = 60 days in the first and second trimesters combined) had a protective effect on preterm delivery (OR = 0.51, 95% CI 0.27-0.95). Television viewing had a U-shaped relation with preterm delivery (ORs (95% CI): < 15 hours, 2.09 (1.21-3.61); 29-42 hours, 1.50 (0.84-2.67); > 42 hours, 3.05 (1.75-5.40)). While the results support current recommendations regarding leisure-time activities, activities of daily living appear to increase risk of preterm delivery among low income women. These findings and those for television watching warrant further investigation.

Non-occupational physical activity during pregnancy and the risk of preterm birth: a meta-analysis of observational and interventional studies

“…Therefore, 37 eligible studies (7 case control studies, 18 cohort studies, and 12 interventional studies) were included in the meta-analysis. All the included 25 observational studies (7 case-control studies and 18 cohort studies) were rated as either high18 or moderate91920212223242526272829303132333435363738394041 quality (see Supplemental Tables S1 and S2). …”

“…It may not be appropriate to combine all domains of PA into a single score and link it to health endpoints including PTB because different domains of PA may have different health impacts. For instance, one study9 found that leisure-time PA was inversely associated with the risk of PTB, but commuting PA appeared to be positively related to the risk.…”

Occupational factors and risk of preterm birth in nurses

“…19, 20 However, individual studies report widely varying results, with relative risks ranging from 0.7 to 5.6 for night or rotating shift work, possibly due to inconsistent definitions of work schedule and insufficient sample sizes in the night or shift work categories. 24, 26, 27, 29, 33, 34, 35 …”

The Impact of Symptoms of Depression and Walking on Gestational Age at Birth in African American Women

“…However, research specifically focused on the relationship between walking for a purpose and preterm birth in African-American women is limited and the results are inconclusive. In a prior study of low income African-American women in Baltimore, the researchers found an increased odds of preterm birth for women who walked for a purpose four days or more per week (Misra, Strobino, Stashinko, Nagey, & Nanda, 1998). In contrast, another study in the same city (different institution) reported that African-American women who walked for a purpose for more than 30 minutes per day during pregnancy had lower risk of preterm birth (Sealy-Jefferson, Hegner, & Misra, 2014).…”

“…In contrast, another study in the same city (different institution) reported that African-American women who walked for a purpose for more than 30 minutes per day during pregnancy had lower risk of preterm birth (Sealy-Jefferson, Hegner, & Misra, 2014). Misra and associates (1998) defined walking for a purpose as the average number of days per week in the first and second trimesters combined that a woman spent walking for a purpose and did not collect duration of walking for a purpose (i.e., minutes per day). In contrast, Sealy-Jefferson and colleagues (2014) asked open-ended questions about the duration of walking for a purpose (minutes per day) which may have decreased recall bias.…”