Role of perceived stress in the occurrence of preterm labor and preterm birth among urban women.

INTRODUCTION

This study examined whether prenatal perceived stress levels during pregnancy were associated with preterm labor or preterm birth.

METHODS

Perceived stress levels were measured at 16 weeks' gestation or less and between 20 and 24 weeks' gestation in a sample of 1069 low-income pregnant women attending Temple University prenatal care clinics. Scores were averaged to create a single measure of prenatal stress. Preterm birth was defined as the occurrence of a spontaneous birth prior to 37 weeks' gestation. Preterm labor was defined as the occurrence of regular contractions between 20 and 37 weeks' gestation that were associated with changes in the cervix.

RESULTS

Independent of potential confounding factors, prenatal perceived stress was not associated with preterm labor (odds ratio [OR], 1.10; 95% confidence interval [CI], 0.69-1.78; P = .66); however, prenatal stress trended toward an association with preterm birth (OR, 1.49; 95% CI, 1.00-2.23; P = .05). The strongest predictor of preterm labor was a history of preterm labor in a prior pregnancy. Women with a history of preterm labor were 2 times more likely to experience preterm labor in the current pregnancy than women who did not have a preterm labor history (OR, 2.16; 95% CI, 1.05-4.41; P = .04). Historical risk factors for preterm birth, such as African American race, a history of abortion, or a history of preterm birth, were not related to preterm labor. The strongest predictor of preterm birth was having a history of preterm birth in a prior pregnancy (OR, 2.55; 95% CI, 1.54-4.24; P < .001).

DISCUSSION

Prenatal perceived stress levels may be a risk factor for preterm birth independent of preterm labor; however, prenatal stress was not associated with preterm labor. Risk factors for preterm labor may be different from those of preterm birth.