MAGNITUDE OF THE PROBLEM

The prevalence of specific birth defects varies widely with the ethnic, geographic, cultural, and economic characteristics of populations (Kuliev and Modell, 1990). The combined prevalence of all birth defects is estimated to be about 4–5 percent of live births in developed countries (Kuliev and Modell, 1990; World Health Organization, 1999; Penchaszadeh, 1994). In the developing countries with stronger health care systems and more complete data on birth defects, the birth prevalence of recognizable birth defects is estimated to be similar to that in developed countries (about 2–3 percent) (Castilla and Lopez-Camelo, 1990; International Clearinghouse for Birth Defects Monitoring Systems, 1998; Heredero, 1992; Delport et al., 1995; Venter et al., 1995; World Health Organization, 1997). Rates may be higher in some developing countries, underscoring the need for better surveillance data. Prevalence at birth represents only part of the total prevalence of birth defects because many conditions are not recognized for months or years after birth (Christianson et al., 1981; World Health Organization, 1997; Venter et al., 1995).

Global burden-of-disease data from 1990 show congenital anomalies to be the tenth leading cause of disability-adjusted life years in developing countries. This estimate, although the best available, is limited by a lack of accurate data on birth defects in many countries and by inadequate data on infants and children for conditions not detected at birth (Murray and Lopez, 1997; World Health Organization, 1999, 2000). What is certain, however, is that birth defects have a severe impact on individuals and their families because they manifest early in development and can cause early death or lifelong impairment. The prognosis for many children with birth defects can be improved only through surgical procedures, which may not be available or affordable. Even those who receive treatment may require long-term care from their families—a particular hardship for families in which more than one member is affected (Penchaszadeh, 1994). Birth defects therefore diminish the productivity and quality of life for affected individuals, for their families and communities, and ultimately for society as a whole.

INCREASE IN THE IMPORTANCE OF BIRTH DEFECTS WITH DECREASING INFANT MORTALITY

Over the last four decades, the average infant mortality rate in developing countries has fallen from 137 to 66 per 1000 live births, largely as a result of improvements in safe childbirth and control of infectious diseases and malnutrition. Progress in lowering infant mortality rates has, however, varied greatly among developing countries. Those that have made the least progress toward this goal—located mainly in sub-Saharan Africa and South Asia—tend to have weaker health care systems (United Nations Children's Fund, 1998). Early progress in sub-Saharan Africa has been checked by the HIV/AIDS epidemic.¹ Most perinatal deaths in sub-Saharan Africa and South Asia are caused by complicated deliveries, birth asphyxia, infections, and low birth weight. In these settings, infant mortality is best addressed by focusing on cost-effective medical services for basic reproductive care and safe delivery, control of infectious diseases, and treatment of nutritional inadequacies (Jenkins, 1977; Stoll and Measham, 2001).

The most impressive reductions in infant mortality rates over the last four decades have been in Latin America and the Caribbean (from 105 to 35 per 1,000 live births), East Asia and the Pacific (133 to 41 per 1,000), and the Middle East and North Africa (154 to 50 per 1,000) (United Nations Children's Fund, 1998). By 1997, infant mortality rates had declined to less than 40 per 1,000 live births in 67 of the 142 developing countries, and 8 more countries had rates between 41 and 50 per 1,000. The population of the 75 countries with infant mortality rates below 50 per 1,000 was 2.8 billion, which represents 60 percent of the population of the developing world (United Nations Children's Fund, 1998).

As infant mortality rates fall, birth defects are responsible for an increasing proportion of the infant mortality and morbidity (Modell and Kuliev, 1989; World Health Organization, 1997, 1999). In the majority of Latin American and Middle Eastern countries that have reduced infant mortality to less than 50 per 1,000, the infant mortality due to birth defects is as high as 25 percent (World Health Organization, 1997), which is similar to the proportion in developed countries.

The increasing role of birth defects in countries that have lowered infant mortality rates is reflected in admissions to pediatric hospitals: 8–19 percent of total admissions in Middle Eastern Countries (World Health Organization, 1997) and 10–25 percent in some urban centers in Latin America. These hospital stays also tend to be longer and more expensive (Penchaszadeh, 1979; Carnevale et al., 1985).

REDUCING BIRTH DEFECTS IN COUNTRIES WITH LOW INFANT MORTALITY

Figure 1-1 shows decreases in the infant mortality rate over the last two decades for North Africa, the Middle East, and Pakistan. As these rates have decreased to a range of 20 to 40 per 1,000, several countries in these regions have introduced genetic screening programs for specific birth defects (Alwan and Modell, 1997). Such programs are less cost-effective than interventions that address basic reproductive care, but they have been identified by these countries as the next essential step in lowering infant mortality rates cost-effectively. In 1981, Cuba established national genetic screening in primary care programs, with referral to secondary and tertiary health care (Heredero, 1992). Cyprus, South Africa, and Iran also have primary care programs with genetic screening for specific birth defects (see Boxes 3-1 and 3-6 in Chapter 3) (Christianson et al., 1995; Christianson, 2000; Gaudet, 1999; Khoury et al., 2000). In many other developing countries, including India and several in Latin America, genetic screening services are accessible only to middle- and high-income patients in the tertiary care centers of major cities (Jenkins, 1990; Penchaszadeh, 1992, 1993).

FIGURE 1-1

Infant mortality rates in North Africa, the Middle East, and Pakistan over two decades.

SOURCE: Alwin and Modell, 1997.

SOCIAL, ECONOMIC, AND HEALTH CONTEXT

Effective strategies to address birth defects in developing countries must consider the competing health needs of these populations, as well as a variety of social, economic, and health system–specific factors that limit resources for health care. These factors include the following (World Health Organization, 1999):

• Financial resources: The average per capita gross national products of developing countries are 10 to 40 times lower than those of developed countries.
• Income distribution: Extreme income inequalities result in a smaller proportion of the population having access to quality health care. In fact, about one-quarter of the combined population of all developing countries survives on less than $1 per day.
• Education: Literacy rates in developing countries range from 57 to 87 percent and are generally lower among women than men.
• Fertility: Developing-country fertility rates are high relative to those of developed countries, particularly among less-educated women.
• Infrastructure: Developing-country populations frequently lack access to safe water (70 percent), adequate sanitation (42 percent), transportation, and communication.
• Infant mortality: Rates of infant mortality in the developing world vary—from as low as 9 deaths per 1,000 live births in Cuba to as high as 191 per 1,000 live births in Niger.
• Burden of disease: By the end of the twentieth century, about 42 percent of all deaths in developing countries were caused by avoidable conditions such as infectious diseases, lack of reproductive health care, and nutritional deficiencies, compared with 6 percent in developed countries.

To address these challenges, programs must be tailored to the needs and resources of communities in each country. The recommendations in this report are intended to guide the development of a capacity to address birth defects that is integrated with and builds on current health care services for mothers, infants, and children.

STUDY PURPOSE

Despite major improvements in the knowledge of birth defects, their incidence and impact remain high in most countries. As infant and neonatal mortality decline, an increasing proportion of adverse outcomes at birth are due to birth defects. This study addresses the steps needed to improve the prevention of and care for birth defects by:

• Reviewing current knowledge and practices for a healthy pregnancy;
• Identifying cost-effective opportunities for prevention of birth defects and support of families with a handicapped infant; and
• Recommending capacity-building, priority research, and institutional and global efforts to reduce the incidence and impact of birth defects in developing countries.

This report is intended to engage a broad spectrum of individuals and organizations that have the potential to lead efforts to address the global impact of birth defects. Such individuals and groups include, but are not limited to, policy makers, health ministries, United Nations agencies, multilateral development banks, international donor agencies, foundations, nongovernmental organizations, professional societies, pharmaceutical and medical-device companies, advocacy groups, health care professionals, researchers, consumer and patient advocacy groups, and interested members of the public. This diverse and influential audience holds the key to raising public awareness and generating the commitment and resources necessary to reduce the burden of birth defects in developing countries.

STUDY APPROACH

The Institute of Medicine (IOM) assembled a study committee with broad international expertise in public health, neonatology, obstetrics, genetics, epidemiology, pediatrics, and clinical research to prepare a report on improving birth outcomes in developing countries. The committee members are listed at the beginning of the report (biographies are provided in Appendix B). This report was prepared by the committee with the assistance of expert consultants to more fully address the issues involved in reducing birth defects. Although most committee members give highest priority to the issues covered in the broader report, they acknowledge the lack of epidemiological information on the rates and disease burden of birth defects in many developing countries; the potential value of several affordable interventions; and, as countries reduce neonatal and infant mortality rates, the increasing proportion of the disease burden caused by birth defects.

The data used for this study were assembled from bibliographic references on related topics and from databases such as MEDLINE, university libraries, and Internet sites of organizations associated with research and services for birth defects. Although much of the published information on these disorders in developing countries was found in international and national journals and reports, some of the evidence has appeared in local journals, proceedings of meetings, and unpublished reports prepared for the World Health Organization and other international organizations. To tap this broad knowledge base, the committee enlisted experts with recent research or service experience in developing countries. Data and evidence were provided by these experts through workshop presentations and technical consultation on the report chapters. The framework for the committee's examination of birth defects included an overview of epidemiological parameters; review of the current knowledge base on interventions; and examination of the feasibility, cost, and impact of proposed interventions. This combination of evidence, the committee believes, is an accurate representation of the state of knowledge concerning the epidemiology of birth defects, their prevention and care in developing countries, and the capacity of local health care systems to undertake prevention and care programs. Evaluation of this evidence enabled the committee to identify gaps in knowledge and to propose strategies for operational research to fill these gaps.

ORGANIZATION OF THE REPORT

The next three chapters address the challenges of birth defects in developing countries. Chapter 2 describes the causes of the major classes and types of birth defects, epidemiological parameters, and the burden of disease in low-resource settings. Chapter 3 describes interventions that can reduce the impact of birth defects: first those that are effective and affordable in settings with limited resources, and then screening services for genetic birth defects that are appropriate for countries in which infant and neonatal mortality rates have been lowered using the most cost-effective interventions. Examples of interventions from developing countries are described in boxes throughout the text. Chapter 4 provides a framework for implementing such interventions in primary health care systems.

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Footnotes

1

Although further discussion of HIV/AIDS is beyond the scope of this report, perinatal transmission of HIV/AIDS is discussed in detail in a companion report, Improving Birth Outcomes: Meeting the Challenge in the DevelopingWorld, also authored by this committee.