Factors associated with insomnia in pregnancy: A prospective Cohort Study.

OBJECTIVE: To quantify insomnia and their components in a longitudinal cohort of pregnant women and factors associated with insomnia.

STUDY DESIGN: A prospective cohort of 486 healthy singleton pregnancies assembled before the 14th gestational week (February 2013 to March 2016). Insomnia data were collected pre-gestationally, in each trimester and six months post-partum, analysing five different moments. Multiple logistic regression analysis was performed to generate adjusted Odds Ratios (aOR) with 95% confidence intervals (CI) of determinants of insomnia in each trimester, defined using Athens Insomnia Scale (AIS) as score ≥8.

RESULTS: Insomnia prevalence was 6.1% (3.9-8.9) pre-gestational, 44.2% (39.3-49.6) in first trimester (T1), 46.3% (41.9-51.3) in second (T2) and 63.7% (57.7-67.8) in third trimester (T3). Post-gestational insomnia was 33.2% (28.2-37.9) (p < 0.001 pre-gestational vs T1, T2 vs T3 and T3 vs after pregnancy). There was worsening mean AIS score, from: 2.34 before pregnancy to 9.87 in T3 because the deterioration of nighttime sleep, in absolute terms, but daytime impact was higher in T1. Previous trimester insomnia was associated with insomnia in T2 (aOR = 4.21, 95% CI 2.78-6.37) and T3 (aOR = 4.43, 95% CI 2.77-7.08). Pre-gestational insomnia was determinant of insomnia in T1 (aOR 12.50, 95% CI 3.58-43.60) and obesity was associated with insomnia in T3 (aOR = 2.30, 95% CI 0.99-5.32). On the contrary, moderate physical activity reduced the odds of insomnia in T3 (aOR 0.65, 95% CI 0.40-1.03).

CONCLUSIONS: Insomnia prevalence was high from the beginning of pregnancy, associated with pre-gestational insomnia. In late pregnancy, two out of three pregnant women suffering insomnia. Insomnia prevention should be targeted particularly to those with high body mass index and pre-gestational insomnia.