Researchers found that among 1,820 pregnant women, those with the greatest concerns about their pregnancy were nearly three times more likely than those with the least anxiety to deliver prematurely. The findings are published in the journal Psychosomatic Medicine.
Stress during pregnancy has been linked to a higher risk of complications in some studies, though not all. And those that have identified a link have not suggested any simple solutions to the problem.
For the current study, researchers looked specifically at women's worries related to their pregnancy -- including anxiety over labor and delivery, and worries about early pregnancy problems like bleeding and nausea. The goal was to see whether the risk of preterm birth was influenced by the types of anxiety that obstetricians can fairly easily address.
For example, a woman's fears about labor might be allayed by a thorough discussion with her doctor, according to the study authors, led by Dr. Suezanne T. Orr of East Carolina University in Greenville, North Carolina.
For their study, the researchers had 1,820 women complete a questionnaire on pregnancy worries during their first visit for prenatal care. The women were asked whether they were anxious about labor and delivery, the health of the baby, nausea, and pain or bleeding during early pregnancy.
They were then given anxiety "scores" ranging from 0 to 6.
Overall, Orr's team found, women who scored a 5 or 6 were at greater risk of preterm delivery than those with lower scores. This remained true when the researchers considered factors that could both fuel women's anxiety and raise the risk of preterm birth -- such as a history of problems in past pregnancies, or health problems during the current pregnancy.
The findings suggest that excessive anxiety itself may contribute to premature delivery in some women, according to Orr and her colleagues.
"If additional research confirms our findings," they write, "then this might suggest an avenue for intervention to reduce spontaneous preterm birth. Anxiety is a treatable condition."
They point out that pregnancy-related worries, in particular, can be addressed with education.
"Pregnant women could receive information from their healthcare providers about the signs and symptoms of a normal pregnancy and the process of labor and delivery to reduce their worries and concerns about pregnancy, and ultimately their risk of spontaneous preterm birth outcomes," the team notes.