In 1999, 27% of deliveries in Hong Kong were by caesarean section (C-section). This high rate of C-section prompted Leung et al1 to explore the consequences of caesarean delivery for the infant's health, with results presented in this issue. Hong Kong is not unique. There has been a striking increase in C-sections in medium- and high-income countries around the world. There are several and complex reasons for this trend.2
C-section is a surgical procedure developed to prevent or treat life-threatening maternal or fetal complications. Changes in medical indications do not explain the recent increases in C-section rates. One reason sometimes mentioned for the increase is women's choice.3 However, at least in Latin American countries, pregnant women still favor vaginal delivery, either because recovery is faster or because it is the natural way to deliver.4,5 This preference is found even among women receiving a C-section and at hospitals with extremely high C-section rates.
What level of C-sections in the population is appropriate? Twenty years ago, the World Health Organization6 recommended that no more than 15% of deliveries should be delivered by C-section, pending evidence that higher levels benefit either mothers or their offspring. Of 60 medium- and high-income countries reviewed in a recent study,7 the majority (62%) had national rates of C-section above 15%. If we assume, based on the World Health Organization recommendations, that C-section rates above 15% lack medical justification, then there are 3.5 million medically unjustified interventions performed among these countries yearly.
What are the consequences of these trends for the health of women and babies? To the extent that high rates of C-sections are not medically indicated, they unnecessarily expose the mother and child to consequences that are not fully understood.7,8 In such procedures, the mother and her partner have no active participation in the birth of their child. The costs and benefits of this elective procedure, both physical and emotional, should be seriously explored before accepting the liberalization of its use.
Elective caesarean section may provide some benefits. A systematic review of 79 studies of elective C-sections versus vaginal deliveries, including observational and randomized trials, has shown that women with C-section have decreased urinary incontinence at 3 months and decreased perineal pain in comparison with those having a vaginal delivery.9 On the other hand, C-section was associated with a higher risk of maternal mortality, hysterectomy, ureteral tract and vesical injury, abdominal pain, neonatal respiratory morbidity, fetal death, placenta previa, and uterine rupture in future pregnancies.10 One limitation of observational studies is that the associations with poor outcomes could be due to the conditions that trigger the C-section rather than the C-section itself, despite statistical efforts to adjust for these confounders. Consequently, the strength of this evidence should be considered with caution.
Two recent reviews of observational or ecological studies have examined the association of C-section rates with maternal and neonatal mortality and morbidity. One is the study mentioned above, using data on 60 medium- and high-income countries of all regions,7 and the other is based on data from Latin American countries.2 Both reviews found no evidence for reductions in maternal and neonatal mortality and morbidity with increases in C-section rates to above 10%. In fact, higher rates of C-section were associated with higher rates of maternal and neonatal mortality and morbidity.2 For example, Barros et al11 showed that, between 1982 and 2004, the C-section rate in one city in southern Brazil increased from 28% to 43%, whereas the preterm birth rate has increased from 6% to 16%. The increase in preterm births occurred despite improvements in socioeconomic and nutritional conditions in the population.11 The increase in C-section rates and also an increase in elective induction of labor contributed to this trend.
Most observational studies have focused on the outcomes of next pregnancy. The study by Leung et al1 provides useful data on the postpartum morbidity of the offspring themselves delivered by C-section. While the authors found no clear evidence of either harm or benefit among the offspring delivered by C-section compared with vaginal delivery, their study is a good example of studies that expand the range of possible outcomes related to mode of delivery. Other outcomes might include short- and long-term maternal satisfaction and maternal-infant bonding.
Given the lack of evidence for substantial benefit from elective C-section and the possibility of substantial harm, research is also needed to better understand the reasons for the rising trends, and to design and test interventions that can reduce unnecessary C-sections. Recent attempts tested in a rigorous trial have resulted in only a small decrease in C-section rates.12
All of the actors involved in women's health care should be aware of the health, economic and social consequences of elective C-section. Women's organizations need to play a relevant part in empowering women to play more participatory roles in their care and to improve their knowledge regarding the rationale for the use of C-sections and the consequences of unnecessary use.
From a different perspective, many are arguing about the need for a trial comparing elective C-section versus an attempt to deliver vaginally.13 Whether such a trial can be justified on an ethical and public health basis is still a matter of debate. In our view, this is not currently a priority question for the developing world.
1. Leung GM, Ho LM, Schooling CM, et al. Health care consequences of caesarean birth during the first 18 months of life: the 1997 Hong Kong Birth Cohort. Epidemiology
2. Villar J, Valladares E, Wojdyla D, et al. Caesarean delivery rates and pregnancy outcomes: the 2005 WHO global survey on maternal and perinatal health in Latin America. Lancet
3. What is the right number of caesarean sections? Lancet
4. Osis MJD, Padua KS, Duarte GA, et al. The opinion of Brazilian women regarding vaginal labor and caesarean section. Int J Gynecol Obstet
5. Potter JE, Berquo E, Perpetuo IH, et al. Unwanted caesarean sections among public and private patients in Brazil: prospective study. BMJ
6. World Health Organization. Appropriate technology for birth. Lancet
7. Althabe F, Sosa C, Belizán JM, et al. Caesarean section rates and maternal and neonatal mortality in low-, medium-, and high-income countries: an ecological study. Birth
8. Belizán JM, Althabe F, Barros FC, et al. Rates and implications of caesarean sections in Latin America: ecological study. BMJ
9. National Collaborating Centre for Women's and Children's Health. Commissioned by the National Institute for Clinical Excellence. Caesarean Section Clinical Guideline, April 2004. Available at http://www.nice.org.uk/page.aspx?o=113190
. Accessed April 11, 2007.
10. Belizán JM, Cafferata ML, Althabe F, et al. Risk of patient choice caesarean. Birth
11. Barros FC, Victora CG, Barros AJ, et al. The challenge of reducing neonatal mortality in middle income countries: findings from three Brazilian birth cohorts in 1982, 1993, and 2004. Lancet
12. Althabe F, Belizán JM, Villar J, et al. Mandatory second opinion to reduce rates of unnecessary caesarean sections in Latin America: a cluster randomised controlled trial. Lancet
13. Lavender T, Kingdon C, Hart A, et al. Could a randomised trial answer the controversy relating to elective caesarean section? National survey of consultant obstetricians and heads of midwifery. BMJ