Risk factors associated with preterm birth at Muhimbili National Hospital, Dar es Salaam, Tanzania: unmatched case control study

Abstract

Background Preterm birth, birth of a baby prior to 37 weeks gestation age, is one of the major public health burdens worldwide. It has far reaching consequences to the mother and the newborn with both short-term and long-term effects. It is estimated that more than one in ten babies were born prematurely worldwide in 2010 making approximately 15 million preterm births, of which more than 1 million died due to the complications of preterm birth. Dealing with premature babies has been seen to pose a number of challenges due to inadequate care provided to these babies. In order to combat this burden, reduction of preterm birth should be highly emphasized. This can be done by first identifying the risk factors associated with preterm birth and then come up with appropriate preventive measures. Objective The objective of this study was to determine the risk factors associated with preterm birth at Muhimbili National Hospital, Dar es Salaam, Tanzania. Methodology Unmatched hospital-based case-control study was conducted between Feb 2015 and April 2016 involving 140 cases who were women who delivered preterm babies between 28 and 36 weeks and 280 controls who were women who delivered term babies at 37 weeks gestation or more at Muhimbili National Hospital. Data collection was through face to face interview using a questionnaire which contained information on socio-demographic characteristics of the women, maternal factors and fetal factors and it was supplemented by maternal data from the case notes and antenatal cards. Data analysis was done using IBM SPSS version 20. Chi square and Odds ratio (OR) with 95% CI were used to assess the relationship between independent variables and dependent variables. T-test was used for continuous variables. Logistic regression was done to find independent risk factors associated with preterm birth. P value < 0.05 was considered significant. Results The prevalence of prematurity in this study was 17.9%. Factors that were independently associated with preterm birth after adjusting for confounders were few number(<2) of antenatal visits (AOR=2.8, 95%CI 1.5-5.1), antepartum hemorrhage (AOR = 6.2, 95% CI 3.3-11.8), maternal hypertension (AOR = 4.9, 95% CI 3.5-6.9), premature rupture of membranes (AOR = 8.4, 95% CI 5.3-13.4), history of preterm birth (AOR = 2.2, 95% CI 1.2-3.9) and history of stillbirth (AOR = 2.1, 95% CI 1.0-4.3) and multiple gestation (AOR = 2.3, 95% CI 1.3-3.9). Conclusion Prematurity still remains one of the major public health burdens. This study has highlighted the prevalence of prematurity in our setting and its associated risk factors. Therefore, early detection of these risk factors is recommended in order to help to improve prenatal care especially in high risk pregnancies in order to prevent preterm birth hence reducing significantly neonatal morbidity and mortality.