Standing Long Hours During Pregnancy Affects Baby's Growth

by James T. Gibson

Working and PregnancyDoes your work require you to stand for long periods of time or to work long hours? If so, your pregnancy working conditions might hamper your baby's growth, especially during the third trimester, a recent study reveals.

Past research raised concerns that certain work-related factors, like long work hours, prolonged standing, psychological job strain, and physical demands, could have negative effects on birth outcomes.

To explore the relationship between work factors, fetal growth, and birth outcomes, researchers from Erasmus University Medical Center looked at data from the Generation R Study, a prospective cohort study tracking participants from birth to young adulthood.

About the Study

The Dutch study team collected data on more than 4600 women who gave birth to a live-born singleton between April 2002 and January 2006. Each woman had paid employment and completed a mid-pregnancy questionnaire about working conditions.

Moms-to-be who had jobs requiring long hours standing, such as sales, child care and teaching, had infants with heads about 1 cm smaller than women who worked in other jobs during their pregnancies, the researchers found.

Working more than 40 hours a week was associated with a smaller head circumference and lower growth rate.

"This effect seems to be of similar magnitude that the effects of other well-known lifestyle factors, such as smoking and caffeine intake," the authors wrote.

These findings may mean that not sitting and working very long hours has a negative effect on the infant's development, Burdorf's group said. There are indications that a smaller head could negatively affect brain development. How it might play into any one child's development isn't predictable. The effect can only be determined by following them over time.

The study team didn't find any adverse outcomes between physically demanding work or long hours, such as preterm labor, small for gestational age or low birth weight babies.

"This study does not present concrete information on the required reduction in duration and level of work demands," Burdorf and colleagues wrote.

It does raise concerns about pregnancy and work-related factors. Preventative measures that reduce certain occupational conditions such as shift work, night hours, standing for long hours and heavy lifting have shown to reduce the risk of birth complications.

In the light of this study, do you think employers should make accommodations for pregnant women?

Medical references:
- Snijder C, et al. (June 27, 2012) "Physically demanding work, fetal growth, and the risk of adverse birth outcomes. The Generation R study" Occup Environ Med 2012; DOI: 10.1136/oemed-2011-100615.