Increasing caesarean section rates among low-risk groups: a panel study classifying deliveries according to Robson at a university hospital in Tanzania

BACKGROUND: Rising caesarean section (CS) rates have been observed worldwide in recent decades. This study sought to analyse trends in CS rates and outcomes among a variety of obstetric groups at a university hospital in a low-income country. METHODS: We conducted a hospital-based panel study at Muhimbili National Hospital, Dar es Salaam, Tanzania. All deliveries between 2000 and 2011 with gestational age ≥ 28 weeks were included in the study. The 12 years were divided into four periods: 2000 to 2002, 2003 to 2005, 2006 to 2008, and 2009 to 2011. Main outcome measures included CS rate, relative size of obstetric groups, contribution to overall CS rate, perinatal mortality ratio, neonatal distress, and maternal mortality ratio. Time trends were analysed within the ten Robson groups, based on maternal and obstetric characteristics. We applied the χ(2) test for trend to determine whether changes were statistically significant. Odds ratios of CS were evaluated using multivariate logistic regression, accounting for maternal age, referral status, and private healthcare insurance. RESULTS: We included 137,094 deliveries. The total CS rate rose from 19% to 49%, involving nine out of ten groups. Multipara without previous CS with single, cephalic pregnancies in spontaneous labour had a CS rate of 33% in 2009 to 2011. Adjusted analysis explained some of the increase. Perinatal mortality and neonatal distress decreased in multiple pregnancies (p < 0.001 and p = 0.003) and nullipara with breech pregnancies (p < 0.001 and p = 0.024). Although not statistically significant, there was an increase in perinatal mortality (p = 0.381) and neonatal distress (p = 0.171) among multipara with single cephalic pregnancies in spontaneous labour. The maternal mortality ratio increased from 463/100, 000 live births in 2000 to 2002 to 650/100, 000 live births in 2009 to 2011 (p = 0.031). CONCLUSION: The high CS rate among low-risk groups suggests that many CSs might have been performed on questionable indications. Such a trend may result in even higher CS rates in the future. While CS can improve perinatal outcomes, it does not necessarily do so if performed routinely in low-risk groups.