Impact of change in maternal age composition on the incidence of Caesarean section and low birth weight: analysis of delivery records at a tertiary hospital in Tanzania, 1999–2005

Projestine S Muganyizi,Hussein L Kidanto

doi:10.1186/1471-2393-9-30

Abstract

BackgroundPrevious studies on change in maternal age composition in Tanzania do not indicate its impact on adverse pregnancy outcomes. We sought to establish temporal changes in maternal age composition and their impact on annual Caesarean section (CS) and low birth weight deliveries (LBWT) at Muhimbili National Hospital in Tanzania.MethodsWe conducted data analysis of 91,699 singleton deliveries that took place in the hospital between 1999 and 2005. The data were extracted from the obstetric data base. Annual proportions of individual age groups were calculated and their trends over the years studied. Multiple logistic analyses were conducted to ascertain trends in the risks of CS and LBWT. The impact of age composition changes on CS and LBWT was estimated by calculating annual numbers of these outcomes with and without the major changes in age composition, all others remaining equal. In all statistics, a p value < 0.05 was considered significant.ResultsThe proportion of teenage mothers (12–19 years) progressively decreased over time while that of 30–34 years age group increased. From 1999, the risk of Caesarean delivery increased steadily to a maximum in 2005 [adjusted OR = 1.7; 95%CI (1.6–1.8)] whereas that of LBWT declined to a minimum in 2005 (adjusted OR = 0.76; 95% CI (0.71–0.82). The current major changes in age trend were responsible for shifts in the number of CS of up to206 cases per year. Likewise, the shift in LBWT was up to 158 cases per year, but the 30–34 years age group had no impact on this.ConclusionThe population of mothers giving birth at MNH is progressively becoming older with substantial impact on the incidence of CS and LBWT. Further research is needed to estimate the health cost implications of this change.

Highlights

Previous studies on change in maternal age composition in Tanzania do not indicate its impact on adverse pregnancy outcomes
Using hospital data in USA, the peak proportion of teenage mothers was recorded in the mid 1970s, but the proportion of older mothers steadily increased in late 1970s [5]
Studies in Africa indicate that overall Sub-Saharan Africa (SSA) has the highest rates of fertility in the world including that for adolescents

Summary

Introduction

Previous studies on change in maternal age composition in Tanzania do not indicate its impact on adverse pregnancy outcomes. Changes in age composition of the childbearing women population can strongly influence birth outcomes, health costs and social welfare of the women [1,2]. Such changes are reported in some countries, but the direction of change could differ between countries and even in the same country with time. 40% rate of teenage pregnancy in USA has remained the highest [3]. Studies in Africa indicate that overall Sub-Saharan Africa (SSA) has the highest rates of fertility in the world including that for adolescents. Since the 1980s, several countries in SSA have begun a transition toward lower fertility with an upward trend in the age at first birth, wide variations still remain across countries and social groups [6]

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