Risk factors of preterm birth in Sri Lanka: case-control study

Introduction: Preterm birth is a major challenge as a contributor to neonatal and child mortality in low- and middle-income countries (LMIC). Many countries toil to prevent and care for preterm babies. Country-specific solid data on risk factors of preterm births are crucial to formulate preventive strategies. Objectives: To determine the antenatal risk factors of preterm births in Sri Lanka Methods: An unmatched case-control study was conducted in seven Government hospitals with obstetric and neonatal care facilities in Colombo District in Sri Lanka. Live-born, spontaneous or provider-initiated, 374 preterm babies (<37 & >24 weeks of gestation) as cases and live-born 374 term babies as controls were recruited from mothers who had a dating scan before 22 weeks. A risk factor profile worked out by extensive literature search and consultation of experts was subjected to multivariable analysis to identify risk factors. Results: Risk factors identified were: multiple pregnancy (adjusted odds ratio (aOR)=10.57; 95% CI: 3.48, 32.08); bleeding/spotting during pregnancy (aOR=3.51; 95% CI: 1.77, 6.98), past preterm birth (aOR= 2.83; 95% CI: 1.09, 7.36), recent stressful life event (aOR=2.62; 95% CI: 1.43, 4.81), higher gravidity (aOR=2.58; 95% CI: 1.35, 4.9), dissatisfaction with self-assessed own health (aOR=2.54; 95% CI: 1.52, 4.22), pregnancy induced hypertension (aOR=2.25; 95% CI: 1.16, 4.38), no antenatal dental assessment (aOR=2.16; 95% CI: 1.23, 3.81), unsatisfactory oral hygiene (aOR=2.01; 95% CI: 1.33, 3.04), long standing hours during 3rd trimester (aOR=1.91; 95% CI: 1.24, 2.94) and cooking using firewood (aOR=1.51; 95% CI: 1.01, 2.25). Sexual abstinence (aOR=0.46; 95% CI: 0.26, 0.81) was a protective factor. Conclusions & Recommendations: Modifiable and unmodifiable factors for preterm births were identified. Special care during pregnancy and early admission is recommended for multiple pregnancy, those had spotting during pregnancy and those had past preterm delivery. Avoiding stress during pregnancy and emphasizing oral hygiene are recommended.