Examining the Impact of Anxiety and Prenatal BMI on Preterm Birth

Anxiety is a significant predictor of preterm delivery. High prenatal BMI is also associated with pregnancy complications such as preterm birth. However, there is a lack of research establishing a relationship between prenatal weight, psychosocial factors, and preterm birth. The purpose of this research is to determine if there is a relationship between prenatal anxiety, BMI and preterm birth. A multi-center longitudinal study of 377 ethnically diverse pregnant women with repeated measures design was used. Women greater than 18 years old with singleton gestation were included. BMI was calculated using first trimester weight (kg) and height (cm). Participants’ weights were categorized based on ACOG groups (81 of normal weight, 53 overweight, 48 obese). Anxiety was measured in all three trimester using the State and trait anxiety inventory (STAI). Data analysis included descriptive statistics, t-tests, and ANOVA using SAS 9.3 and an alpha of 0.05. Overall, there was no significant difference in anxiety score across the trimesters, with the highest anxiety reported in third trimester (1st: 34.4; 2nd: 32.9; 3rd: 34.5). First trimester BMI was not associated with anxiety or preterm birth (p=.34; p=.16 respectively). In the third trimester, there was a significant difference between mean STAI score when comparing term and preterm birth (p=.05). There was no association in the 2nd trimester (p=.69); however, this relationship approached significance in the 1st trimester (p=.06). When examining anxiety scores by ethnicity, African American (AA) women consistently reported the highest anxiety scores in each trimester; whereas Caucasian (CA) women reported the lowest. There were significant differences between AA and CA anxiety scores in the first and third trimesters (p=.01; p=.01 respectively). Maternal anxiety in the third trimester is significantly associated with preterm birth. Prenatal BMI does not appear to affect anxiety scores throughout pregnancy. Anxiety scores were consistently highest among AA women and lowest among CA women. These data support the need for assessment of anxiety throughout pregnancy, especially in high risk populations. Future research should investigate interventions to reduce anxiety in high risk women