Preterm birth

Birth – what means too soon, too small, too sick?

Every year, about 140 million babies are born. About 30 millions of them require special care and about 10 million need intensive care each year to survive and thrive, because they are born too soon, small or sick. About 2.5 million newborns die within their first 28 days from preventable causes and about 1.3 million survive with major disabilities. To achieve the Sustainable Development Goal to end preventable newborn deaths, all countries must reduce neonatal mortality to 12 deaths or less per 1000 live births by 20301.

Too soon

A pregnancy usually lasts for approximately 37 to 42 weeks. Healthcare professionals have defined different gestational stages in which babies are born:

Every baby born before completion of 37 weeks of pregnancy is born too soon and considered as born “preterm”, before term. Preterm babies did not have enough time to be fully developed. They are born with immaturely developed organs and most of them need special care2.

Worldwide situation
Worldwide, estimated 15 million babies are born preterm annually – 10% of all newborns worldwide. The range of the preterm birth rate varies from country to country from about 5% to 18%. There are huge inequalities in survival rates around the world. In high-income countries, 50% of the babies born extremely preterm with 24 weeks survive, while in low-income settings only 50% survive when they are born at 32 weeks gestational age. This low rate of survival is due to a lack of basic care, like warmth, breastfeeding support, and treatments of infections. Preterm birth complications are the main cause of global under-5 deaths and many survivors face a lifetime of disability, including learning disabilities and visual and hearing problems3.

Causes & risk factors
Preterm birth occurs for a variety of reasons. The majority of preterm births happen spontaneously. Experts have identified several factors, which may increase the risk of preterm birth: Medical conditions, as infections and genetic predispositions, lifestyle factors, as overweight, smoking or high stress levels, as well as demographic factors, as young or old age or socio disadvantages. Some risk factors are “modifiable,” meaning they can be changed to help reduce the risk, while others cannot be changed. However, in about 50% of cases no cause for the baby born too early can be identified. 4/5

Too small

The concept of small for gestational age (SGA) describes babies who are smaller than the usual average for the number of weeks of pregnancy. The definition of SGA is not dependent on the height, but the birth weight being below the 10th percentile. SGA is caused by intrauterine growth restriction (IUGR) due to genetic predispositions or insufficient supply of nutrients, or by physiological reasons, such as unusual small parents 6.

Worldwide situation
About 32 million babies, 27% of the livebirths in low- and middle-income countries are born SGA. The SGA rate is especially high in South Asia, the Sahel region and India [7]. IUGR is the second leading cause of perinatal mortality after preterm birth. Foetuses which are suffering from IUGR have a 5 to 10 times higher risk to die during pregnancy 8.

Causes & risk factors
IUGR has many adverse consequences on the survival, health, growth and development. The most important risk factor in IUGR is poor maternal nutrition. This not only includes the nutritional status during pregnancy, but also before conception. An additional factor is a short mother’s stature due to undernourishment or infections during childhood. Especially in middle-or high income countries, the highest risk factor for IUGR is smoking. 7/9

Too sick

Before, during and in the days after birth, children are especially vulnerable to develop diseases and disorders. Some of these are in severe conditions, which can result in long-term health impairments for the children and their families.

This includes the development of genetically determined disorders, like phenylketonuria, sickle cell anaemia, or any physiological impairments, perinatal health issues, like birth asphyxia, newborn health issues, like jaundice, infections/fever, diarrhoea, Retinopathy of prematurity (ROP) or Respiratory syncytial virus (RSV).
Additionally, maternal infections can be transferred to the newborn, for example Malaria or human immunodeficiency viruses (HIV). Several other diseases threaten the foetus or newborns, like cerebral palsy, spina bifida, Fragile X syndrome, or foetal alcohol and drug-related syndromes.

Worldwide situation
In low and middle income countries, about 6.9 million newborns need specialised or intensive care due to severe infections, such as sepsis, meningitis, pneumonia every year. Worldwide about 7 to 14 million need basic resuscitation at birth, 1.2 million have severe diseases of the brain (encephalopathy) and due to jaundice about half a million newborns need treatment. Other birth defects, such as spina bifida or genetical disorders are diagnosed in about 1.3 million newborns. 1

Causes & risk factors
Causes and risk factors for diseases or disabilities of newborns are various, but often preventable by a high quality care around the time of birth for mother and child. Undernourishment of mother and child, undiagnosed and untreated infections as well as inaccessible professional healthcare play major roles in developing or long-term suffering from diseases or disabilities.

1 Survive and thrive: transforming care for every small and sick newborn. Geneva: World Health Organization; 2019. Licence: CC BY-NC-SA 3.0 IGO.

2 Martin, Richard J., Avroy A. Fanaroff, and Michele C. Walsh. Fanaroff and Martin’s Neonatal-Perinatal Medicine E-Book: Diseases of the Fetus and Infant. Elsevier Health Sciences, 2010.

3 World Health Organization. “Born too soon: the global action report on preterm birth.” (2012).

4 Goldenberg R, Culhane J, Iams JD, Romero R. Epidemiology and causes of preterm birth. 2008. The Lancet. 371(9606): 75–84.

5 Keller M, Saugstad O, van Steenbrugge G, Mader S, Thiele N. European Foundation for the Care of Newborn Infants. Caring for Tomorrow. EFCNI White Paper on Maternal and Newborn Health and Aftercare Services.Munich 2011.

6 Müller-Egloff S. (2006) Small for Gestational Age (SGA) Infants, intrauterine
Wachstumsretardierung (IUWR/IUGR). In: Geburtshilfe Basics. Springer, Berlin, Heidelberg

7 Embleton ND, Katz J, Ziegler EE (eds): Low-Birthweight Baby: Born Too Soon or Too Small. Nestlé Nutr Inst Workshop Ser. Nestec Ltd. Vevey/S. Karger AG Basel, 2015, vol 81, pp 1-7.

8 Suhag, Anju, and Vincenzo Berghella. “Intrauterine growth restriction (IUGR): etiology and diagnosis.” Current Obstetrics and Gynecology Reports 2.2 (2013): 102-111.