Relaxation of the one child policy and trends in caesarean section rates and birth outcomes in China between 2012 and 2016: observational study of nearly seven million health facility birthsBMJ 2018; 360 doi: https://doi.org/10.1136/bmj.k817 (Published 05 March 2018) Cite this as: BMJ 2018;360:k817
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Re: Relaxation of the one child policy and trends in caesarean section rates and birth outcomes in China between 2012 and 2016: observational study of nearly seven million health facility births
We commend this extensive ecological study of almost 7 million births over a five-year period in China assessing the impact of relaxation of the "one child policy" on cesarean delivery rates. Global cesarean delivery rates are a critically important topic. Cesarean delivery is the most common operation conducted worldwide, yet many cesarean deliveries may be conducted without clinical indication. Cesarean deliveries are associated with increased risk of short-term complications (e.g. blood loss, infection and venous thrombosis) as well as the potentially catastrophic long-term consequences, including life threatening hemorrhage secondary to abnormal placentation and unplanned hysterectomy compared to vaginal deliveries.(1-4)
Nonetheless, there are some caveats that we wish to highlight when interpreting the results of this paper.
1. The authors state that "adjusting the time trends for institutional, sociodemographic, and obstetric characteristics reduced the relative risk [of cesarean] to 0.82 (0.81 to 0.84), suggesting that caesarean section rates declined by 18% between 2012 and 2016." This is an inaccurate interpretation of the statistical analysis and the authors appear to be conflating relative risk and absolute risk in this statement. According to Table 2, the overall cesarean rate in 2012 was 45% and decreased to 41.1% by 2016. We agree that the risk of cesarean delivery decreased over time by 18% (RR =0.82, 95% CI: 0.81 to 0.84); however, the absolute reduction was 4.8% percentage points, or percent change from 2012 to 2016 was 9.3%. Thus, the statement that the cesarean delivery rates declined by 18% is incorrect.
2. The largest gains in reduction of cesarean delivery in this study were observed in nulliparous (37.9%) and multiparous women (18.5%) without a previous uterine scar Moreover, women who had the fewest antenatal visits, with no education or unmarried women had the lowest cesarean delivery rates, but the authors did not hypothesize why this may be the case. Does the socioeconomic status and educational attainment of women impact their choices or are there other financial incentives and social dynamics at play which were not explored?
3. There has been no change in cesarean rates of women with prior uterine scars over the study period with rates remaining stable at around 90% as well an increased incidence of uterine rupture in women with prior uterine scars. These findings may reflect a lack of consistent management of women with uterine scars who wish to have a vaginal delivery. Additionally, there was no mention of the availability of neuraxial analgesia for laboring women. Many women may opt for a repeat cesarean delivery rather than attempt a trial of labor with a scar if there is no/limited epidural availability for pain relief. In the United States, there was a movement toward promoting vaginal birth after cesarean (VBAC) in the 1990s, however controversies about the safety of this method prompted a sharp decline in this mode of delivery.(5) However, in the UK, almost 50% of women attempt VBAC of which almost 60% achieve a successful vaginal delivery giving an overall VBAC rate of about 28%.(6)
4. The authors also contend that "...caesarean section rates were high in women with direct obstetric complications (83.1%) or medical diseases (51.2%)" yet give no evidence of the clinical indications for the cesarean deliveries in this study. They also claim that higher level hospitals did more cesarean deliveries than lower level hospital which was "...fully explained by the varying sociodemographic and obstetric characteristics of the women…" and that even women with no high-risk condition had high rates of cesarean deliveries (40.1%). When risk adjusting for women with medical conditions, variation in cesarean delivery rate is increased, not decreased, indicating that other mechanisms are at play when clinicians decide to deliver by cesarean.(7)
5. Cesarean delivery reduction was only seen in hospitals with extremely high rates (>60%). Increased scrutiny at these hospitals could be capturing low-hanging fruit; whether the rates can be lowered further or sustained is questionable as rates remained stable in hospitals with moderately high rates (20-39%) and actually increased in those with low rates (<20%).
6. The authors describe a variety of top-down interventions, which they believe have reduced cesarean delivery rates, including clinician and patient educational efforts, audit and feedback strategies and payment reform implemented since 2009. Yet, there is no description of how these policies were implemented or the receptivity of clinicians to educational and audit efforts. Without this understanding, it is challenging to draw generalizable lessons from the results.
7. The statement that China is the only country that has reversed rising trends in cesarean delivery rates is inaccurate. Many countries are working to address this exact issue with some success. Examples include: 1) The United States has been active in reducing cesarean rates with clinical guidance and broad professional alignment to reduce unnecessary cesarean delivery, and in the past five years, primary cesarean rates have started to fall.(5,8) 2) Brazil has one of the highest cesarean rates in the world and has shown evidence of reducing cesarean trends by increasing rate of vaginal birth from 21.6% to 38% over 18 months in 26 public and private hospitals.(9) 3) Portugal has also shown a steady decline in cesarean delivery rates since 2009 using concerted action including provider education and use of cesarean delivery rates as a quality marker for hospital funding.(10)
8. The cumulative impact of cesarean delivery on adverse outcomes after relaxing the one-child policy is likely not apparent due to the short time frame (2013-2016). Most women would only have one additional birth, if any, in those 3 years. We probably a longer time period and higher parity at a population level to detect a change in rare adverse outcomes from cumulative surgical risks.
We look forward to hearing the authors' responses to our comments and questions.
1. Witt WP, Wisk LE, Cheng ER, et al. Determinants of Cesarean Delivery in the US: A Lifecourse Approach. Matern Child Health J. 2015;19(1):84-93. doi:10.1007/s10995-014-1498-8.
2. Silver RM, Landon MB, Rouse DJ, et al. Maternal Morbidity Associated With Multiple Repeat Cesarean Deliveries. Obstet Gynecol. 2006;107(6):1226-1232. doi:10.1097/01.AOG.0000219750.79480.84.
3. Clark EAS, Silver RM. Long-term maternal morbidity associated with repeat cesarean delivery. Am J Obstet Gynecol. 2011;205(6):S2-S10. doi:10.1016/j.ajog.2011.09.028.
4. Lindquist SAI, Shah N, Overgaard C, et al. Association of Previous Cesarean Delivery With Surgical Complications After a Hysterectomy Later in Life. JAMA Surg. 2017;122(1):70-74. doi:10.1001/jamasurg.2017.2825.
5. Martin JA, Hamilton BE, Osterman MJ, Driscoll AK, Matthews TJ. Births: Final Data for 2015. Natl Vital Stat Reports. 2017;66(1).
6. Cromwell D, Senior N, Miss MA, et al. National Maternity and Perinatal Audit A snapshot of NHS maternity and neonatal services in England, Scotland and Wales in January 2017.
7. Kozhimannil KB, Arcaya MC, Subramanian S V., et al. Maternal Clinical Diagnoses and Hospital Variation in the Risk of Cesarean Delivery: Analyses of a National US Hospital Discharge Database. Smith GC, ed. PLoS Med. 2014;11(10):e1001745. doi:10.1371/journal.pmed.1001745.
8. ACOG. ACOG - Safe Prevention of the Primary Cesarean Delivery.
9. Institute for Healthcare Improvement: IHI and Brazil's Hospital Israelita Albert Einstein Expand Successful Approach to Reduce Unnecessary C-Sections. http://www.ihi.org/about/news/Pages/Expand-Successful-Approach-Reducing-.... Accessed March 23, 2018.
10. Ayres-De-Campos D, Cruz J, Medeiros-Borges C, Costa-Santos C, Vicente L. Lowered national cesarean section rates after a concerted action. Acta Obstet Gynecol Scand. 2015;94(4):391-398. doi:10.1111/aogs.12582.
Competing interests: No competing interests
It is stated by Juan Liang and co-workers that “Overuse of caesarean section (SC) adversely affects the health of the mother and the child”  with references to [2,3]. However, there are no such or similar statements in [2,3]. The first sentence of  reads: “Caesarean delivery can improve maternal and child health” . It is also pointed out that “much of the evidence linking caesarean delivery to chronic disease is observational” . The commentary  concludes: “Given the lack of evidence for substantial benefit from elective CS and the possibility of substantial harm, research is also needed” and “From a different perspective, many are arguing about the need for a trial comparing elective SC versus an attempt to deliver vaginally” , which can be agreed with.
The well-known advantage of elective CS is the relatively low risk of foetal injury and negative association of neonatal mortality and morbidity in term pregnancy . Some reports on enhanced maternal morbidity/mortality may be biased as they confound CS with diseases related to maternal death that do not depend on the mode of delivery [5,6]. Therefore, CS may be a potential marker for pre-existing morbidities rather than a risk factor of itself . In a logistic regression model adjusted for 5 maternal age groups and severe preeclampsia, women who had CS were not at significantly higher risk for pregnancy-related death compared to those who had vaginal delivery . Moreover, in regard to certain maternal complications e.g. pelvic floor injury and postpartum urinary incontinence elective CS was reported to be protective compared to vaginal delivery and emergent CS [8,9].
Finally, CS facilitates tubal sterilization. It should be mentioned that tubal ligation has been associated with a decreased risk of endometrioid and serous ovarian cancers , that female sterilization probably has a positive impact upon sexuality (unless the woman has been ambivalent over the procedure) , and that the majority of women are pleased with their decision to be sterilized . Admittedly, CS as a form of delivery is associated with a higher risk in areas with limited medical facilities; however, surgical procedures generally tend to improve. In the author’s opinion, CS with tubal sterilization should be considered for women not planning further pregnancies, which is of particular importance for populations with excessive birth rate .
1. Juan Liang, Yi Mu, Xiaohong Li, et al. Relaxation of the one child policy and trends in caesarean section rates and birth outcomes in China between 2012 and 2016: observational study of nearly seven million health facility births. BMJ 2018;360:k817.
2. Blustein J, Liu J. Time to consider the risks of caesarean delivery for long term child health. BMJ2015;350:h2410.
3. Belizán JM, Althabe F, Cafferata ML. Health consequences of the increasing caesarean section rates. Epidemiology2007;18:485-6.
4. Machado Júnior LC, Sevrin CE, et al. Association between mode of delivery and neonatal deaths and complications in term pregnancy: a cohort study in Brazil. Minerva Pediatr 2014;66(2):111-22.
5. Kilsztajn S, Carmo MS, Machado LC Jr, et al. Caesarean sections and maternal mortality in Sao Paulo. Eur J Obstet Gynecol Reprod Biol 2007;132(1):64-9.
6. Nomura RM, Alves EA, Zugaib M. Maternal complications associated with type of delivery in a university hospital. Rev Saude Publica 2004;38(1):9-15.
7. Lydon-Rochelle M, Holt VL, Easterling TR, Martin DP. Cesarean delivery and postpartum mortality among primiparas in Washington State, 1987-1996(1). Obstet Gynecol 2001;97(2):169-74.
8. Salim R, Shalev E. Health implications resulting from the timing of elective cesarean delivery. Reprod Biol Endocrinol 2010;8:68.
9. Di Stefano M, Caserta D, Marci R, Moscarini M. Urinary incontinence in pregnancy and prevention of perineal complications of labour. Minerva Ginecologica 2000;52:307-12.
10. Walker JL, Powell CB, Chen LM, et al. Society of Gynecologic Oncology recommendations for the prevention of ovarian cancer. Cancer 2015;121:2108-20.
11. Shah MB, Hoffstetter S. Contraception and sexuality. Minerva Ginecol 2010;62:331-47.
12. Contraception by female sterilisation. Br Med J 1980;280(6224):1154-5.
13. Jargin SV. Demographical aspects of environmental damage and climate change. Climate Change 2015;1(3):158-60. https://www.researchgate.net/publication/279533880_Demographical_aspects...
Competing interests: No competing interests