Preterm birth and low birth weight
Globally, preterm birth (i.e. birth before 37 completed weeks of gestation) is the leading cause of death in children under 5 years of age, responsible for approximately 1 million deaths in 2015 (see indicator “Under age 5 mortality” in Chapter 3). In almost all countries with reliable data, preterm birth rates are increasing. Many survivors of preterm births also face a lifetime of disability, including learning disabilities and visual and hearing problems as well as long-term development (WHO, 2018[4]).
In LAC, most countries are near the regional average of 9.5% of births being preterm. Colombia is the only country significantly above average with near 15% of preterm births, followed by Brazil with 11%. The lowest rates were observed in Cuba (6%) and Mexico (7%) (Figure 4.3, left panel). Most LAC countries rates are lower than the global rate, but there are opportunities for further improvements through interventions such as a national focus on improved obstetric and neonatal care, and the systematic establishment of referral systems with higher capacity of neonatal care units and staff and equipment (Howson, Kinney and Lawn, 2012[5]). On average, 10 new-borns out of 100 had low weight at birth across LAC countries (Figure 4.3, right panel). There are very significant differences between countries in the region, ranging from a low 5% in Cuba and 6% in Chile, to the highest rate of 23% in Haiti, followed by Guyana with 16%.
Low birth weight has decreased an average of 0.4 percentage points in LAC26 countries in the 2000-15 period, suggesting that, overall, the region still has room for improvement in regards to this indicator. Chile, Brazil, Venezuela and Costa Rica are the only LAC countries to have increased low birth weight new-borns, while the largest reduction happened in Surinam, Guatemala and Honduras with more than 1 percentage point of decrease between 2000 and 2015 (Figure 4.4).
Antenatal care can help women prepare for delivery and understand warning signs during pregnancy and childbirth. Higher coverage of antenatal care is associated with higher birth weight in LAC countries, suggesting the significance of antenatal care over infant health status across countries (Figure 4.5). However, the correlation does not apply equally in all countries. For instance, Trinidad and Tobago and Barbados report to have 100% and 98% of at least four antenatal care visits, but their low birth weight prevalence is 12%, over the LAC average of 10%. This might be explained partly by a low quality of care in their antenatal care visits. On the other hand, countries like Grenada, Paraguay and Bolivia show an antenatal care coverage below the LAC24 average of 87%, but also a low birth weight prevalence of 7-9%. Some of the differences between countries can be attributed to cultural practices and preferences, such as different approaches to privacy or perceptions about what antenatal and postnatal care entail.
Preterm birth can be largely prevented. Effective interventions to reduce preterm births include smoking cessation, progesterone supplementation, cervical cerclage, preterm surveillance clinics and screening, diagnosis and preparation, corticosteroids, magnesium sulphate, and tocolysis (Osman, Manikam and Watters, 2018[6]). Most of these exist in several LAC countries and could be further developed. In addition, three-quarters of deaths associated with preterm birth can be saved even without intensive care facilities. Current cost-effective interventions include kangaroo mother care (continuous skin-to-skin contact initiated within the first minute of birth), early initiation and exclusive breastfeeding (initiated within the first hour of birth) and basic care for infections and breathing difficulties (WHO, 2018[4]), all of which can also be scaled up in LAC countries.
Preterm birth is defined as babies born alive before 37 weeks of pregnancy are completed. There are sub-categories of preterm birth based on gestational age: extremely preterm (less than 28 weeks); very preterm (28-32 weeks); moderate to late preterm (32-37 weeks). Low birthweight is defined by the World Health Organization as the weight of an infant at birth of less than 2 500 grammes (5.5 pounds) irrespective of the gestational age of the infant. This figure is based on epidemiological observations regarding the increased risk of death to the infant and serves for international comparative health statistics. In developed countries, the main information sources are national birth registers. For developing countries, low birthweight estimates are primarily derived from mothers participating in national household surveys, as well as routine reporting systems (WHO and UNICEF, 2004[7]).
Antenatal care (ANC) is defined as the care provided by skilled health-care professionals to pregnant women and adolescent girls in order to ensure the best health conditions for both mother and baby during pregnancy. The recommendation is to provide at least four visits during pregnancy (WHO, 2016[8]).
References
[5] Howson, C., M. Kinney and J. Lawn (eds.) (2012), Born Too Soon: The Global Action Report on Preterm Birth, World Health Organization, Geneva, https://www.who.int/maternal_child_adolescent/documents/born_too_soon/en/.
[6] Osman, R., L. Manikam and K. Watters (2018), “Interventions to reduce premature births: a review of the evidence”, The Lancet, Vol. 392, p. S69, https://doi.org/10.1016/s0140-6736(18)32188-3.
[7] WHO and UNICEF (2004), Low birthweight: country, regional and global estimates, World Health Organization, https://apps.who.int/iris/handle/10665/43184.
[8] WHO (2016), WHO recommendations on antenatal care for a positive pregnancy experience, World Health Organization, https://www.who.int/reproductivehealth/publications/maternal_perinatal_health/anc-positive-pregnancy-experience/en/.
[4] WHO (2018), Preterm birth, World Health Organization, https://www.who.int/news-room/fact-sheets/detail/preterm-birth.
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Source: UNICEF, 2019.
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Source: UNICEF-WHO Low birthweight estimates, 2019.
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Source: WHO GHO 2018.