Analysis of global trends in caesarean section rates using the Robson classification

Cesarean section (CS) is the most widespread surgery in the world, and the worldwide upward trend has been observed for recent decades. According to the latest data, one in five women gives birth by a surgical operation [1]. The percentage of abdominal delivery is an important global indicator to measure access to obstetric services [2].

Since 1985, in the international community of healthcare specialists, it has been accepted to consider that an ideal indicator of the CS frequency shall not be more than 10.0–15.0% of all childbirths. According to the WHO data, the frequency of abdominal delivery correlates, within 10.0%, with the decrease in maternal and perinatal mortality, and the increase in this parameter does not give any advantages for a mother and her child, excluding the situation when operative delivery is essential [3].

In many countries (especially in the countries with a high level of income), for the last three decades, the rate of CS has been steadily on the rise [4]. Some authors reason that such circumstance is significantly defined by the increased use of the non-medical CS delivery according to a patient’s desire [5].

In the view of some authors, the CS performed without indications increases the frequency of unfavorable obstetric and perinatal outcomes [6].

The steadfast growth of the CS frequency made the global community conduct trials to determine effective measures aimed at a safe decrease in the operative delivery frequency. Nevertheless, the adopted measures demonstrated a low efficiency [7][8].

As a global standard for the assessment, monitoring, and comparison of the CS indicators in medical institutions and between them, the World Health Organization (WHO) and International Federation of Gynecology and Obstetrics (FIGO) recommend using Robson’s classification (RC) [9][10][11].

The RC uses the primary obstetric characteristics to classify all women admitted to labor by dividing them into 10 mutually exclusive and fully inclusive groups (Table 1). 

Table 1

In 2011, Torloni et al. evaluated 27 classifications for the CS assessment, which had been published in 1968–2008. The following parameters were evaluated: simplicity, clarity, mutually excluding categories, fully inclusive classification, prospective identification of categories, reproducibility, and feasibility. Female classifications demonstrated the best results, while other types of classifications require data that are not routinely acquired and may not always be relevant. The results of this study showed a possibility to use the RC for audit, analysis, and comparison of the CS frequency [12].

The global leading position in terms of the abdominal delivery frequency is occupied by Brazil which is one of the first Latin American countries where surgeons began doing CS at a woman’s request without medical indications, and operative deliveries became a part of the established cultural stereotype. In Brazil, the healthcare system is funded through both governmental and private sources [13][14].

In 2019, the study “Robson Classification System Applied to the Brazilian Reality” was published. Therein, Brazilian hospitals were divided into “typical” (standard perinatal care) and “atypical” (specialty care) with having named “typical” institutions as child good-minded hospitals. The CS level was substantially lower in “atypical” inpatient clinics as compared to “typical” ones (47.8% and 90.8%, respectively) [15]. In 2020, Rudey et al. carried out the study “Cesarean Section Rates in Brazil: Trend Analysis Using the Robson Classification System.” According to the obtained data, in Brazil, from 2014 to 2017, 11,774,665 live births were recorded. Therewith, the CS rate was 55.8%. In the regions with a high index of human development, significantly higher indicators were noted as compared with the regions with a low level of birthrates. The share of Robson’s groups (RGs) I – IV is 60.2% live births and 47.1% of all CS. Attention is drawn to the fact that RGs I–IV are precisely the ones that represent favorable conditions for vaginal deliveries. Thereupon, nulliparous patients from RGs I and II are classified into RG V while increasing the CS global level by 1% per annum. In 2016, in Brazil, a study was conducted with the purpose to determine whether the delivery source of funding has any influence on the rate of operative delivery [16]. According to the data of this study, the CS rate amounted to 42.9% in the public healthcare sector and 87.9% in the private healthcare sector. The patients of RGs II, V, and X contributed significantly to the structure of operative delivery both in public and private clinics. The share of these patients was more than 70% of operative labor. Nevertheless, only in the public sector, the patients of a risk category had substantially higher indicators of CS as compared to women with a low risk almost in all RGs.

In 2020, the results of a study conducted in the USA were published [17]. The authors used the RC for comparing the rate of operative deliveries in the hospitals where midwives worked and in the inpatient clinics with no midwives in their staff. In this study, the data of 90,000 patients having performed delivery for 2002–2008 were analyzed. In inpatient clinics where midwives assisted in providing medical care, lower indicators of labor induction in RG II (11.1% against 23.4%) and CS (26.1% against 33.5%), as well as higher indicators of vaginal delivery following a prior abdominal delivery (73.8% against 85.1%), were noted. The CS rate in women with a higher risk of complications was the same in both categories of hospitals. In 2018, the data of the population-based analysis “Cesarean Delivery in the United States 2005 through 2014: A Population-based Analysis Using the Robson’s 10-Group Classification System” were published [18]. This population-based analysis applied the RC system to 27,044,217 labors performed in the United States of America from 2005 to 2014. The total CS rate was 31.6. The labors in RG III were widespread, and the labors in RG V included the greatest part of abdominal deliveries. The percent in this group was increased from 27% of all CS in 2005–2006 to 34% in 2013–2014. In RGs VI and VII, the CS rate was above 90%.

The study performed in Canada in 2020 covered 286,201 labors performed for the period 2016–2017. In RG V, the operative delivery rate was 80.5%. This was precisely the group that had had a major contribution to the CS level (36.6%). In the women, the labor of which was induced (RG II), the CS rate was nearly twice as high as in the women with spontaneous labor (RG I) 33.5% and 18.4%, respectively. These two groups had a similar amount contribution to the total level of abdominal delivery (15.7% and 14.1%, respectively) [19].

The study performed in Iceland covered the period of 2005–2014. For 10 years, 88,004 mothers brought into life 89,649 children of a weight ≥ 500 g; the share of women older than 35 years roses from 28.4% to 39.4%, and the rate of abdominal delivery annually increased by 0.6% (from 18.3% to 23.5%). The main contribution to the CS rate increase was made by RGs II and V. In RG V, no increase in the CS rate was noted [20].

In Turkey, in 2017, the CS total level was 51.2%. To analyze the CS high level, electronic records of 887,683 women, which had been sent by public, private, and university hospitals, were examined. The CS rate in public, private, and university hospitals amounted to 39.7%, 70.6%, and 70.3%, respectively, which gives evidence of significant differences between private and public sectors. Further evaluations were performed to reveal a rank order of RGs influencing the CS indicators. RGs I–V and X were six groups comprising more than 80% of women present in medical institutions. The women of RG V fulfilled a prevailing role with 25.2% by the group size and 24.4% by a contribution to the final CS indicator. Thirty-two and 3 tenth percent of women were included in RGs I and II with the total level of abdominal delivery of 19.6% and 59.6%, respectively. RGs III and IV included 32.9% of women, with the CS indicators of 11.2 and 36.8%, respectively, and a contribution of both groups to the final indicator of 5.6%. All single pregnancies with the <37 stage of gestation in RG X were 3.1% of the entire group with a contribution of 2.3% to the CS indicator. The CS total level for RG X was 70.5%. Investigators made unpromising conclusions on the consequences of the commercialization for the healthcare system and the necessity of focusing the public policy on the private sector where 44.7% of labors occur and where the CS indications are not determined by medical reasons to the full extent.

In 2020, the CS level analysis results for 27 member states of the EU, as well as Iceland, Norway, Switzerland, and the United Kingdom, were published [22]. The CS rate varied from 16.1 to 56.9%. In the countries where the RC is used, the CS rate was lower than in the countries without these data (25.8% against 32.9%). Based on the conducted study, the authors made conclusions on the efficiency of the CS routine use for the implementation of scientifically grounded CS policy on a national scale. In 2014, a multi-center study was carried out in 13 maternity hospitals in France. The CS rate in 2014 corresponded to 19% (2924 of 15,413 labors). The maximum contribution to the total indicator was made by RGs I, II, and V with respective shares of 14.3%, 16.7%, and 32.1% of CS [23]. In 2016, the study “Can We Decrease Cesarean Rate at a University Hospital Treating High-Risk Pregnancies?” was conducted. According to the provided data, to decrease the CS rate without negative influence on perinatal outcome, large experience in managing vaginal deliveries in patients with breech position, thorough selection of patients for inducing labors, differentiation of indications for scheduled operative delivery, such as multiple pregnancy and uterine scar, are favorable [24].

In 2020, the article “Impact of National Guidelines on the Cesarean Delivery Rate in France: a 2010–2016 Comparison Using the Robson Classification” was published. The CS level was 20.5% in 2010 and 19.5% in 2016. Therewith, the CS share before eutocia was reduced (10.9% against 9.2%). RG V more significantly contributed to the rate both in 2010 and in 2016 (5.8% and 5.4%, respectively). The conducted study allowed making conclusions on the efficiency of clinical protocols and national guidelines for making decisions on the way of delivery and reducing the rate of abdominal delivery [25].

Taking into account the significant growth of CS in Italy in 2015, the large-scale study “Identification of Obstetric Targets for Reducing Cesarean Section Rate Using the Robson Ten Group Classification In A Tertiary Level Hospital” was performed [26]. The period from 1998 to 2011 with 17,886 deliveries was analyzed. In women with previous CS (RG V), a subsequent CS was routinely performed, which led to the maximum increase in the CS rate. A significant contribution to increasing the rate of operative delivery was made by RG I and II patients.

In 2015, the global analysis “Use of the Robson Classification to Assess Caesarean Section Trends in 21 Countries: A Secondary Analysis of Two WHO Surveys” was carried out [27]. The authors examined labors performed at 287 institutions in 21 countries, which were included both in “Global Survey on Maternal and Perinatal Health” and in “WHO Multicountry Survey on Maternal and Newborn Health” [28][29].

These data were used to determine an average annual percentage change in the CS rate in each country. States were stratified in accordance with a group of the Human Development Index (HDI) (very high/high/moderate/low). In fact, the CS rate taken as a whole increased between the two surveys (from 26.4% to 31.2%) in all countries, except Japan. The use of obstetric interventions (induction, CS) rose. The abdominal delivery rate increased in a majority of RGs in all categories regardless of HDI. The CS share with labor induction and before eutocia rose in the countries with very high/high, and low HDI, and the rate of operative delivery after induction in patients with multiple pregnancies rose in all groups. The share of women with previous CS along with the CS indicator for these women increased in the countries with moderate and low HDI. According to the conducted analysis, the strategy on decreasing the CS rate should include both the refusal of the first CS unnecessary from a medical point of view and improvement of the selection of patients for inducing labors and conducting abdominal delivery before eutocia.

One of the studies covered data on using CS in more than 33 million women from 31 countries [30]. Authors analyzed “what works, what does not work, and how it might be improved.” Users of the RC appreciated the simplicity, reliability, reproducibility, and flexibility of its classification, its clinical significance. A good consensus existed among the investigators that the classification may be used to reduce the CS rate, as well as may help in the analysis of a contribution of induced labor to the total CS rate [31].

Resources necessary to implement the classification are considered to be minimal, which makes it suitable for low-resource settings. This classification testifies that the information on a significant increase in the rate of operative deliveries in patients with breech positions and multiple pregnancies is contrary to fact.

Users determine the following RC disadvantages: this scale does not take into account other factors of a mother and fetus, which substantially influence the CS rate (for example, the maternal age, former conditions, or complications), and thus to take these factors into account, it is necessary to introduce additional variables.

So, under conditions of the worldwide growth of the rate of abdominal delivery, further modification of the scale will allow not only assessing the CS rate but also estimating the levels of perinatal morbidity and mortality in the groups that made the weightiest contribution to the CS level. Worldwide trends of labor commercialization require global approaches necessary to reduce the level of abdominal delivery in the population.