Ana Pilar Betrán

The worldwide incidence of preterm birth: a systematic review of maternal mortality and morbidity

OBJECTIVE To analyse preterm birth rates worldwide to assess the incidence of this public health problem, map the regional distribution of preterm births and gain insight into existing assessment strategies. METHODS Data on preterm birth rates worldwide were extracted during a previous systematic review of published and unpublished data on maternal mortality and morbidity reported between 1997 and 2002. Those data were supplemented through a complementary search covering the period 2003-2007. Region-specific multiple regression models were used to estimate the preterm birth rates for countries with no data. FINDINGS We estimated that in 2005, 12.9 million births, or 9.6% of all births worldwide, were preterm. Approximately 11 million (85%) of these preterm births were concentrated in Africa and Asia, while about 0.5 million occurred in each of Europe and North America (excluding Mexico) and 0.9 million in Latin America and the Caribbean. The highest rates of preterm birth were in Africa and North America (11.9% and 10.6% of all births, respectively), and the lowest were in Europe (6.2%). CONCLUSION Preterm birth is an important perinatal health problem across the globe. Developing countries, especially those in Africa and southern Asia, incur the highest burden in terms of absolute numbers, although a high rate is also observed in North America. A better understanding of the causes of preterm birth and improved estimates of the incidence of preterm birth at the country level are needed to improve access to effective obstetric and neonatal care.

The Increasing Trend in Caesarean Section Rates: Global, Regional and National Estimates: 1990-2014

Background Caesarean section (CS) rates continue to evoke worldwide concern because of their steady increase, lack of consensus on the appropriate CS rate and the associated additional short- and long-term risks and costs. We present the latest CS rates and trends over the last 24 years. Methods We collected nationally-representative data on CS rates between 1990 to 2014 and calculated regional and subregional weighted averages. We conducted a longitudinal analysis calculating differences in CS rates as absolute change and as the average annual rate of increase (AARI). Results According to the latest data from 150 countries, currently 18.6% of all births occur by CS, ranging from 6% to 27.2% in the least and most developed regions, respectively. Latin America and the Caribbean region has the highest CS rates (40.5%), followed by Northern America (32.3%), Oceania (31.1%), Europe (25%), Asia (19.2%) and Africa (7.3%). Based on the data from 121 countries, the trend analysis showed that between 1990 and 2014, the global average CS rate increased 12.4% (from 6.7% to 19.1%) with an average annual rate of increase of 4.4%. The largest absolute increases occurred in Latin America and the Caribbean (19.4%, from 22.8% to 42.2%), followed by Asia (15.1%, from 4.4% to 19.5%), Oceania (14.1%, from 18.5% to 32.6%), Europe (13.8%, from 11.2% to 25%), Northern America (10%, from 22.3% to 32.3%) and Africa (4.5%, from 2.9% to 7.4%). Asia and Northern America were the regions with the highest and lowest average annual rate of increase (6.4% and 1.6%, respectively). Conclusion The use of CS worldwide has increased to unprecedented levels although the gap between higher- and lower-resource settings remains. The information presented is essential to inform policy and global and regional strategies aimed at optimizing the use of CS.

A global reference for fetal-weight and birthweight percentiles

BACKGROUND Definition of small for gestational age in various populations worldwide remains a challenge. References based on birthweight are deficient for preterm births, those derived from ultrasound estimates might not be applicable to all populations, and the individualised reference can be too complex to use in developing countries. Our aim was to create a generic reference for fetal weight and birthweight that overcame these deficiencies and could be readily adapted to local populations. METHODS We used the fetal-weight reference developed by Hadlock and colleagues and the notion of proportionality proposed by Gardosi and colleagues and made the weight reference easily adjustable according to the mean birthweight at 40 weeks of gestation for any local population. For application and validation, we used data from 24 countries in Africa, Latin America, and Asia that participated in the 2004-08 WHO Global Survey on Maternal and Perinatal Health (237,025 births). We compared our reference with that of Hadlock and colleagues (non-customised) and with that of Gardosi and colleagues (individualised). For every reference, the odds ratio (OR) of adverse perinatal outcomes (stillbirths, neonatal deaths, referral to higher-level or special care unit, or Apgar score lower than 7 at 5 min) for infants who were small for gestational age versus those who were not was estimated with multilevel logistic regression. FINDINGS OR of adverse outcomes for infants small for gestational age versus those not small for gestational age was 1·59 (95% CI 1·53-1·66) for the non-customised fetal-weight reference compared with 2·87 (2·73-3·01) for our country-specific reference, and 2·84 (2·71-2·99) for the fully individualised reference. INTERPRETATION Our generic reference for fetal-weight and birthweight percentiles can be easily adapted to local populations. It has a better ability to predict adverse perinatal outcomes than has the non-customised fetal-weight reference, and is simpler to use than the individualised reference without loss of predictive ability. FUNDING None.

Inequities in the use of cesarean section deliveries in the world

OBJECTIVE The purpose of this study was to describe the unequal distribution in the performance of cesarean section delivery (CS) in the world and the resource-use implications of such inequity. STUDY DESIGN We obtained data on the number of CSs performed in 137 countries in 2008. The consensus is that countries should achieve a 10% rate of CS; therefore, for countries that are below that rate, we calculated the cost to achieve a 10% rate. For countries with a CS rate of >15%, we calculated the savings that could be made by the achievement of a 15% rate. RESULTS Fifty-four countries had CS rates of <10%, whereas 69 countries showed rates of >15%. The cost of the global saving by a reduction of CS rates to 15% was estimated to be

Classifications for Cesarean Section: A Systematic Review

2.32 billion (US dollars); the cost to attain a 10% CS rate was

WHO Statement on Caesarean Section Rates

432 million (US dollars). CONCLUSION CSs that are potentially medically unjustified appear to command a disproportionate share of global economic resources.

Maternal BMI and preterm birth: A systematic review of the literature with meta-analysis

Background Rising cesarean section (CS) rates are a major public health concern and cause worldwide debates. To propose and implement effective measures to reduce or increase CS rates where necessary requires an appropriate classification. Despite several existing CS classifications, there has not yet been a systematic review of these. This study aimed to 1) identify the main CS classifications used worldwide, 2) analyze advantages and deficiencies of each system. Methods and Findings Three electronic databases were searched for classifications published 1968–2008. Two reviewers independently assessed classifications using a form created based on items rated as important by international experts. Seven domains (ease, clarity, mutually exclusive categories, totally inclusive classification, prospective identification of categories, reproducibility, implementability) were assessed and graded. Classifications were tested in 12 hypothetical clinical case-scenarios. From a total of 2948 citations, 60 were selected for full-text evaluation and 27 classifications identified. Indications classifications present important limitations and their overall score ranged from 2–9 (maximum grade = 14). Degree of urgency classifications also had several drawbacks (overall scores 6–9). Woman-based classifications performed best (scores 5–14). Other types of classifications require data not routinely collected and may not be relevant in all settings (scores 3–8). Conclusions This review and critical appraisal of CS classifications is a methodologically sound contribution to establish the basis for the appropriate monitoring and rational use of CS. Results suggest that women-based classifications in general, and Robsons classification, in particular, would be in the best position to fulfill current international and local needs and that efforts to develop an internationally applicable CS classification would be most appropriately placed in building upon this classification. The use of a single CS classification will facilitate auditing, analyzing and comparing CS rates across different settings and help to create and implement effective strategies specifically targeted to optimize CS rates where necessary.

Ecological study of effect of breast feeding on infant mortality in Latin America

In 1985 when a group of experts convened by the World Health Organization in Fortaleza, Brazil, met to discuss the appropriate technology for birth, they echoed what at that moment was considered an unjustified and remarkable increase of caesarean section (CS) rates worldwide.1 Based on the evidence available at that time, the experts in Fortaleza concluded: ‘there is no justification for any region to have a caesarean section rate higher than 10–15%’.1 Over the years, this quote has become ubiquitous in scientific literature, being interpreted as the ideal CS rate. Although this reference range was intended for ‘populations’, which are defined by geopolitical boundaries, in many instances it has been mistakenly used as the measurement for healthcare facilities regardless of their complexity or other characteristics. In addition to the case mix of the obstetric population served, the use of CS at healthcare facilities is also affected by factors such as their capacity to handle cases, availability of resource and the clinical management protocols used locally.

Use of the Robson classification to assess caesarean section trends in 21 countries: a secondary analysis of two WHO multicountry surveys

Objectives. To examine the association between high prepregnancy maternal body mass index (BMI) and the risk of preterm birth (PTB). Methods. A systematic review of the literature. We included cohorts and case-control studies published since 1968 that examined the association between BMI and PTB of all types, spontaneous (s), elective and with ruptured membranes (PPROM) in three gestational age categories: general (<37 weeks), moderate (32–36 weeks) and very (<32 weeks) PTB. Results. 20,401 citations were screened and 39 studies (1,788,633 women) were included. Preobese (BMI, 25–29.9) and obese I (BMI, 30–34.9) women have a reduced risk for sPTB: AOR = 0.85 (95% CI: 0.80–0.92) and 0.83 (95% CI: 0.75–0.92), respectively. Their risk for moderate PTB was 1.20 (95% CI: 1.04–1.38) and 1.60 (95% CI: 1.32–1.94), respectively. Obese II women (BMI, 35–40) have an increased risk for PTB in general (AOR = 1.33, 95% CI: 1.12–1.57) moderate (AOR = 2.43, 95% CI: 1.46–4.05) and very PTB (AOR = 1.96, 95% CI: 1.66–2.31). Obese III women (BMI > 40) have an even higher risk for very PTB (AOR = 2.27, 95%CI: 1.76–2.94). High BMI does not modify the risk for PPROM and increases the risk for elective PTB. Conclusions. High maternal BMI may have different effects on different types of PTB.

Outdoor Air Pollution, Preterm Birth, and Low Birth Weight: Analysis of the World Health Organization Global Survey on Maternal and Perinatal Health

Abstract Objective: To estimate the effect of exclusive breast feeding and partial breast feeding on infant mortality from diarrhoeal disease and acute respiratory infections in Latin America. Design: Attributable fraction analysis of national data on infant mortality and breast feeding. Setting: Latin America and the Caribbean. Main outcome measures: Mortality from diarrhoeal disease and acute respiratory infections and nationally representative breastfeeding rates. Results: 55% of infant deaths from diarrhoeal disease and acute respiratory infections in Latin America are preventable by exclusive breast feeding among infants aged 0-3 months and partial breast feeding throughout the remainder of infancy. Among infants aged 0-3 months, 66% of deaths from these causes are preventable by exclusive breast feeding; among infants aged 4-11 months, 32% of such deaths are preventable by partial breast feeding. 13.9% of infant deaths from all causes are preventable by these breastfeeding patterns. The annual number of preventable deaths is about 52 000 for the region. Conclusions: Exclusive breast feeding of infants aged 0-3 months and partial breast feeding throughout the remainder of infancy could substantially reduce infant mortality in Latin America. Interventions to promote breast feeding should target younger infants. What is already known on this topic Infant mortality is lower among breast fed than non-breast fed infants The reductions are greatest for deaths from diarrhoeal disease and acute respiratory infections What this study adds Exclusive breast feeding of infants aged 0-3 months and partial breast feeding for the remainder of the first year would prevent about 52 000 infant deaths a year in Latin America This corresponds to 13.9% of infant deaths from all causes Promotion of breast feeding has an important role in increasing survival of infants