The research team at the UW School of Medicine and Public Health evaluated 13 different studies of environmental, psychological and biological stress factors for mothers before and during pregnancy.
In general, the most consistent relationship seen was between pre-conception stress and poor obstetric outcomes such as pre-term birth. Women who reported pre-conception “environmental” stress from life events, such as the death of a close relative, were more likely to have a pre-term birth or have an infant who was small for its gestational age.
The association between stress during pregnancy and birth outcomes was more complicated. Environmental stress during pregnancy was significantly associated with a higher risk of pre-term birth in some but not all of the studies. It was also associated with a higher risk for having a low-birthweight infant but not with fetal loss, spontaneous abortion or stillbirth.
Poor obstetric outcomes are serious public health problems and account for more than 40 percent of all neonatal deaths and a substantial proportion of neural developmental disabilities in the United States.
“Up until recently, the focus in this field has been on how stress during pregnancy may influence birth outcomes,” said Dr. Whitney P. Witt, assistant professor in the department of population health sciences and principal investigator in the Lifecourse Epidemiology and Family Health (LEAF) lab.
“However, we are beginning to realize that stress before pregnancy may be just as important, or even more important, than stress during pregnancy. Figuring out which time periods are the most sensitive to stress, like early childhood, adolescence, or the period right before pregnancy, will be critical in determining how to prevent stress from negatively impacting women’s pregnancies and the health of their babies.”
More comprehensive studies examining stress influences on birth outcomes are necessary, according to Witt, because gaps exist in the research to date.
This study is published online in the Maternal and Child Health Journal. This study was funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, and the National Children’s Study Wisconsin Study Center.
University of Wisconsin School of Medicine and Public Health