Prevalence and factors associated with preterm birth at Kenyatta national hospital

Abstract

Background: The World Health Organization (WHO) estimates the prevalence of preterm birth to be between 5 and 18% across 184 countries. Most countries lack reliable data on the burden of preterm birth with only 65 countries having had such data in 2010. Of the estimated 3 million neonatal deaths occurring globally each year, about 1 million are directly related to prematurity. The burden of prematurity has further hindered the achievement of Millennium Development Goal (MDG)-4. Kenyatta National Hospital (KNH) is the largest referral and teaching hospital in Kenya and handles many high risk pregnancies whose outcomes include preterm birth. Despite this, few studies have been carried out locally to determine the prevalence of as well as factors associated with preterm delivery. Objective: To determine the prevalence and the factors associated with preterm birth at Kenyatta National Hospital. Design: A hospital based cross-sectional descriptive study. Setting: Maternity unit, Kenyatta National Hospital, Nairobi. Methods: All mothers who had live births at Kenyatta National Hospital and their newborns were included in the study. Mothers were interviewed using a standard pretested questionnaire to identify factors associated with preterm birth. Additional data was also extracted from maternal records. The mothers’ nutritional status was assessed using MUAC measured on the left. Gestational age was assessed clinically using the Finnstrom Score. Results: A total of 322 mother-baby pairs were enrolled into the study. The mean maternal age (± standard deviation) was 26±5 while most mothers (83%) were married and had attained postprimary education (85%). There was no difference between the socio-demographic preterm deliveries was 39±3 and 33±3 weeks respectively while the mean weight was 3059 ±538 grams and 2031±585 grams respectively. The prevalence of preterm birth in KNH was found to be 18.3% (95% CI of 14.1-22.5). Parity ≥ 4, previous preterm birth, multiple gestation, pregnancy induced hypertension (PIH), antepartum hemorrhage (APH), prolonged preterm prelabor rupture of membranes (PPROM) and urinary tract infection (UTI) in pregnancy were all significantly associated with preterm birth (p=<0.05). On logistic regression, only PIH, APH and prolonged PPROM remained significant. Marital status, maternal level of education, smoking, alcohol use in pregnancy, maternal occupation, ANC attendance, HIV status, anaemia, low maternal MUAC and interpregnancy interval were not associated with preterm birth. APH and parity ≥ 4 were more associated with early than late preterm (OR=4.7 versus 1.7 and OR=6.2 versus 3.9 respectively) while those who had multiple gestation had an almost 7 fold risk of delivering late preterms (OR=6.7). Conclusion: The prevalence of preterm birth in KNH was 18.3%. Parity ≥ 4, previous preterm birth, twin pregnancy, PIH, APH, preterm PROM and UTI were associated with preterm birth. PIH, APH and prolonged PPROM were independent determinants of preterm birth. APH and parity were predictors of early preterm birth while multiple gestation and UTI were strongly associated with late preterm delivery. At-risk mothers should receive intensified antenatal care to mitigate preterm birth.