Trends of caesarean delivery from 2008 to 2017, Mexico

Abstract Caesarean delivery rates in Mexico are among the highest in the world. Given heightened public and professional awareness of this problem and the updated 2014 national guidelines to reduce the frequency of caesarean delivery, we analysed trends in caesarean delivery by type of facility in Mexico from 2008 to 2017. We obtained birth-certificate data from the Mexican General Directorate for Health Information and grouped the total number of vaginal and caesarean deliveries into five categories of facility: health-ministry hospitals; private hospitals; government employment-based insurance hospitals; military hospitals; and other facilities. Delivery rates were calculated for each category nationally and for each state. On average, 2 114 630 (95% confidence interval, CI: 2 061 487–2 167 773) live births occurred nationally each year between 2008 and 2017. Of these births, 53.5% (1 130 570; 95% CI: 1 108 068–1 153 072) were vaginal deliveries, and 45.3% (957 105; 95% CI: 922 936–991 274) were caesarean deliveries, with little variation over time. During the study period, the number of live births increased by 4.4% (from 1 978 380 to 2 064 507). The vaginal delivery rate decreased from 54.8% (1 083 331/1 978 380) to 52.9% (1 091 958/2 064 507), giving a relative percentage decrease in the rate of 3.5%. The caesarean delivery rate increased from 43.9% (869 018/1 978 380) to 45.5% (940 206/2 064 507), giving a relative percentage increase in the rate of 3.7%. The biggest change in delivery rates was in private-sector hospitals. Since 2014, rates of caesarean delivery have fallen slightly in all sectors, but they remain high at 45.5%. Policies with appropriate interventions are needed to reduce the caesarean delivery rate in Mexico, particularly in private-sector hospitals.


Introduction
Caesarean delivery is a vital procedure to reduce maternal and neonatal mortality. 1 However, in some middle-and high-income settings, caesarean deliveries have increased sharply. 1 Although no clear optimal rate has been established as a threshold, a caesarean delivery rate of up to 19 per 100 live births is associated with the lowest rates of maternal and neonatal mortality at a population level. 2 Caesarean delivery rates in Mexico, a country with the second largest economy in Latin America 3 and with a population of nearly 120 million 4 , are among the highest in the world. For example, the national rate of caesarean delivery in first-time mothers was 48.7% (292 445/600 124) in 2014, with higher rates in private facilities than non-private facilities, regardless of type of insurance coverage. 5 These rates are of concern because high rates of caesarean delivery can result in harmful consequences for both the mother and baby. 6,7 The government 8,9 and the public 9 have been aware of this problem since the early 2000s. More recently, two newspaper articles 10,11 described several cases of unnecessary caesarean delivery, those performed without medical indication, 12,13 and subsequent morbidity. These cases indicate that Mexico has a high burden of harmful overtreatment during childbirth.
The health ministry reported a considerable increase in unnecessary caesarean deliveries in the public and private sectors in 2002 9 and provided guidelines for indications to perform caesarean deliveries and strategies to reduce their frequency. 9 In 2014, the ministry published updated guidelines to further reduce caesarean deliveries. 14 In the same year, the Mexican Social Security Institute (IMMS), a government affiliated employment-based insurance network, also published clinical practice guidelines to reduce the frequency of caesarean deliveries. 8 The clinical practice guidelines were widely disseminated and endorsed by other governmentaffiliated employment-based insurance networks (Institute for Social Security and Services for State Workers, and PEMEX -Mexican Petroleum), the health ministry, military sectors, and academia. Mexico's national policy on caesarean delivery was again updated in 2016. 15 Given the heightened public and professional awareness of the high rate of caesarean delivery and the 2014 updated national guidelines to reduce the frequency of caesarean deliveries, 8,14 we analysed the trends in caesarean delivery in health-care facilities in Mexico from 2008 to 2017 to assess their impact on caesarean delivery.

Study design and data source
We conducted an ecological analysis of data from publicly available birth certificates from the General Directorate for Health Information of the Mexican health ministry for the period 2008 to 2017. 16 This data set includes all annual live births with a birth certificate in Mexico and provides demographic and clinical information on both mothers and their newborns.

Variables
We extracted data on the following variables for each of the 32 Mexican states and overall: total live births; mode of delivery (vaginal delivery, caesarean delivery, forceps-assisted vaginal delivery; complicated delivery such as vaginal breech delivery, other modes of delivery and unspecified mode of delivery); and the organizations funding the facility where delivery occurred. The healthcare facilities were the health ministry; the Mexican Social Security Institute (IMSS), a tax-funded government institution that provides employment-based insurance and health services to its beneficiaries and retirees; IMSS-Oportunidades, a government programme that extends social and health services to rural and urban, marginalized and indigenous populations; the Institute for Social Security and Services for State Workers, which provides health-care coverage for government employees; PE-MEX, which provides health-care coverage for its employees, retirees and their families; the Office for National Defence, which provides health-care coverage for its employees, retirees and family members of individuals affiliated with Mexico's army and air force; the Office for the Navy which provides health-care coverage for its employees, retirees and family members of individuals affiliated with the Mexican Navy; and other public and private facilities, roadside delivery (on the way to a health-care facility), home delivery, other, and unspecified.
The outcome variables were the total number of vaginal, caesarean and other deliveries, which were categorized into five types of facility: (i) healthministry hospitals, (ii) private hospitals, (iii) government employment-based insurance hospitals (Social Security Institute, IMSS-Oportunidades, Institute for Social Security and Services for State Workers, and PEMEX), (iv) military hospitals (Office for National Defence and Office for the Navy), and (v) other facilities. Delivery rates were calculated for each category of health facility and overall, nationally and by state. We calculated the difference in the rates of vaginal and caesarean delivery between 2008 and 2017 and present this relative change in rate as a percentage of the 2008 rate.

Statistical analysis
We performed multivariable logistic regression with the year as a continuous covariate to test for trends and determine if there were statistically significant differences (P < 0.05) between rates of caesarean delivery within each type of facility over time, using the health-ministry facilities as the reference category. Statistical analyses were performed using SAS 9.4 (SAS Institute, Cary, United States of America).  (Table 1).

Findings National and state
Data for 2008 show substantial variation in the overall rates of caesarean delivery by state, ranging from 31% in Nayarit, San Luis Potosi and Zacatecas to 51% in Nuevo Leon (Fig. 2). In the private sector, the variation was even greater than the overall rates, ranging from 56% in Chihuahua to 83% in Nuevo Leon (Fig. 3). In 2017, overall rates of caesarean delivery varied considerably by state, ranging from 31% in Chiapas to 53% in Nuevo Leon (Fig. 2). Again, in the private sector, the variation was even greater, ranging from 61% in San Luis Potosi to 92% in Tamaulipas (Fig. 3). Fig. 4 and Fig. 5 show the rates of caesarean delivery in health-ministry and employment-based insurance hospitals, respectively, in 2008 and 2017.
The rates of vaginal and caesarean delivery by state are shown in Table 2. In most states (25 out of 32), the rate of      The change in the rate of caesarean delivery over this 10-year period in government employment-based insurance facilities was statistically significant compared with the change in rate in the public sector (P < 0.001).
Caesarean delivery rates in government employment-based insurance facilities decreased from 44.9% in 2014, when the clinical practice guidelines were published, to 41.2% in 2015 and thereafter plateaued. In

Military facilities
In military facilities, there were 12 875 (95% CI: 12 116-13 633) deliveries a year on average between 2008 and 2017, of which 7522 (95% CI: 7159-7884) were vaginal deliveries and 5285 (95% CI: 4831-5739) were caesarean deliveries. In military facilities, 58.4% of births were vaginal delivery and 41.0% were caesarean delivery, with little variation over time (Fig. 1). The number of live births in military facilities decreased by 23.7% (from 13 924 to 10 628) during the 10-year period. The rate of vaginal delivery increased by 1.4 percentage points (from 58.7% to 60.1%; Table 3) giving a relative percentage increase in the rate of vaginal delivery of 2.4%. The rate of caesarean delivery decreased by 1.6 percentage points (from 40.8% to 39.2%; Table 3), giving a relative percentage increase in the rate of caesarean delivery of 4.0%. There was no statistically significant difference in the change in rate of caesarean delivery in military facilities over this 10-year period compared with the change in rate in the public sector (P = 0.28).   (Fig. 1). There was a 31.6% decrease (from 101 317 to 69 262) in the total number of live births during this 10-year period. The rate of vaginal delivery decreased by 3.5 percentage points (from 73.5% to 70.0%; Table 3), giving a relative percentage decrease in the rate of vaginal delivery of 4.7%. The rate of caesarean delivery increased by 2.4 percentage points (from 25.6% to 28.0%; Table 3), giving a relative percentage increase in caesarean delivery of 9.3%. There was no statistically significant difference in the change in the rate of caesarean delivery in other facilities over this 10-year period compared with the change in rate in the public sector (P = 0.39).

Discussion
Caesarean delivery rates are still alarmingly high in Mexico and increased between 2008 and 2017, with the big-gest increase in private hospitals. These trends were statistically significant in the private and the employment-based insurance facilities compared with health-ministry facilities. However, in 2015 and 2016, after the 2014 clinical practice guidelines were published, rates of caesarean delivery decreased slightly in all types of facility, although they rose again in 2017 in all but health-ministry facilities. These findings illustrate the difficulty in implementing and sustaining change across a mulitsectoral healthcare system.
The 2014 clinical practice guidelines of the Social Security Institute aimed to reduce the number of unnecessary caesarean deliveries. 8 Our subanalysis of trends in caesarean deliveries in Social Security Institute facilities showed an Lack of compliance with the recommendations on caesarean delivery could be associated with factors at different levels: the health system and facilities, health professionals, and patients and their communities. Regarding health system and facility factors, the healthcare infrastructure varies widely by sector and state, including in human resources, labour rooms and quality committees to evaluate caesarean deliveries. Health professionals may resist following updated clinical guidelines because of habit and perverse financial incentives (e.g. they get paid more for caesarean deliveries than vaginal deliveries). For women and the community, health professionals need to provide clear and accurate information about the benefits of vaginal delivery, including the options for pain control, and for caesarean delivery when clinically indicated. Reinforcing the dissemination and implementation of the clinical guidelines and regulating financial incentives are both needed to ensure health professionals follow the national policy on caesarean delivery.
Nationally, one could argue that the national policy had a positive effect because caesarean delivery rates showed a slight, but promising decrease in 2015. Unfortunately, after 2015, the overall rates have gradually increased, but have not reached the 2014 level. States showed variation in caesarean delivery rates; states with more resources had higher overall caesarean delivery rates than those with fewer resources, on average. In all states, the lowest caesarean delivery rates were in health-ministry hospitals (except Oaxaca in 2017 where the lowest rate was in government employment-based insurance facilities) and the highest rates were in private facilities in both 2008 and 2017. States where caesarean delivery decreased or increased considerably over the 10-year period should be further investigated to identify strategies that work and do not work so that successful interventions can be tailored and applied in other states.
The large difference between caesarean delivery rates in the private sector compared with other sectors is a cause for concern. Factors that may explain this difference include perverse economic incentives which exist at all levels of the health-care system: at the health system level (i.e. insurance coverage for caesarean delivery only), facility level (i.e. for-profit hospitals), 17 and the physician level (i.e. induced demand for caesarean delivery, 18 increased income through higher reimbursement for caesarean delivery than vaginal delivery). In addition, patients' perceptions and preferences (e.g. fear of pain during delivery) 19 can affect caesarean delivery rates. In fact, while policies on caesarean delivery provide useful guidance aimed at reducing the number of unnecessary caesarean deliveries based on clinical evidence, the technical guideline also highlights two points of concern: that some insurance policies only cover caesarean delivery and not vaginal delivery, and that women are requesting caesarean delivery rather than vaginal delivery to avoid pain, the slow progression of labour and perceived harm to their newborns with vaginal delivery.
The policies and guidelines are unlikely to reverse the trend in caesarean delivery unless they are part of a multilevel, multistakeholder approach that has continuing support. 8 A multipronged approach tailored to the local context that includes clinical and nonclinical health-care interventions has been proposed as a means to optimize the use of caesarean delivery. 12 For example, a mandatory second opinion before a caesarean delivery can be performed has been proposed. 20 Some suggested non-clinical interventions that are relevant to Mexico include: sharing appropriate evidence-based information on caesarean and vaginal delivery with women and their communities; creating financial arrangements that do not reward caesarean delivery and penalize vaginal delivery; and strengthening systems to provide trained staff and adequate pain relief in childbirth care. 12,21 While higher socioeconomic status has been associated with an increase in caesarean delivery, 22,23 vulnerable populations, such as indigenous groups, are also at risk of unnecessary caesarean delivery and should be monitored when assessing the effect of policies on caesarean delivery. 23 Unfortunately, vulnerable populations who had access to health care through Mexico's universal healthcare insurance, Seguro Popular, might again be at risk, given current attempts to abolish it. 24 Reversal of imperfect yet successful programmes such as Seguro Popular is likely to negatively affect efforts to reduce caesarean delivery in the public sector. If these programmes are reduced or abolished, the effect on maternal and neonatal health care, including on caesarean delivery, will require close monitoring and further research.
Mexico has a robust data collection system with several publicly-available data sets. However, improvements could be made in capturing relevant indicators of maternal and neonatal health, creating a system for quality assurance of data, and standardizing the definitions and classification of variables. Indications for caesarean delivery are poorly documented in both public and private sectors, which could be improved through audits and feedback. 13 In addition, linking data sets, using unique record identifiers that protect the identity of individuals, is important, so that the clinical effects of high rates of caesarean delivery can be monitored over time, such as, hysterectomy during caesarean because of abnormal placentation.
Our study has two main limitations. First, we used publicly available data from birth certificates and births that occurred without a birth certificate were not included. Second, the analysis is based on live births and important information on maternal outcomes from stillbirths and abortions is not captured. Despite these limitations, the data set covers about 98% of Mexico's population. 25

Conclusion
Reducing caesarean delivery rates in Mexico will require more than public awareness, guidelines and policies. First, an improved data collection and quality assurance system is necessary to better understand the consequences of Caesarean delivery, Mexico Tarsicio Uribe-Leitz et al.