Unit 1: The Importance of Optimal Nutrition for Preterm Infants

The definition of a preterm infant is an infant born before completion of 37 weeks of gestation. The World Health Organization (WHO) uses the following categories when describing preterm infants:

Source: ENeA own, information from WHO et al. 2012

In 2012 the WHO published "Born Too Soon: The Global Action Report on Preterm Birth" with global statistics on preterm birth and suggested approaches to address this enormous public health problem (WHO et al. 2012). Despite medical progress, the rate of preterm birth is rising in most countries and ranges from 5-18% of all births, an estimated 15 million babies each year. Preterm birth is the leading cause of death among infants under 4 weeks of age. Many of these deaths would be preventable, even without advanced technology or expensive treatments. The rates of preterm birth across countries are quite varied (Figure 1), with areas in sub-Saharan Africa and Southern Asia showing the highest regional rates of preterm birth (WHO et al. 2012).

Preterm birth comprises a heterogeneous spectrum of underlying causes, which can be divided into two broad sub-groups: spontaneous preterm and provider-initiated preterm birth (Blencowe et al. 2012). Spontaneous preterm is a multifactorial process, in which a number of risk factors can play a role (Romero et al. 2014):

• Age: Young mothers and older mothers have a higher risk of preterm birth (Chen et al. 2007)

• Pregnancy spacing: short pregnancy interval is linked to early labor (DeFranco et al. 2014)

• Multiple pregnancy

• Maternal chronic medical conditions: diabetes, anemia, hypertension, asthma, thyroid disorders
  

• Maternal infections: HIV, urinary tract infections, malaria, chorioamnionitis, bacterial vaginosis

• Undernutrition, micronutrient deficiencies, obesity (Johansson et al. 2014)

• Smoking, alcohol consumption, recreational drug use, air pollution exposure (Chang et al. 2015)

• Excess of physical activity and work

• Depression, psychosocial stress (Raisanen et al. 2014, Cardwell 2013)

• Genetic background and family history of preterm birth (Burris & Collins 2010)

• Cervical incompetence

• Previous cervical dilatation and curettage to manage pregnancy loss (McCarthy et al. 2013)

• Intra-uterine growth restriction

• Congenital abnormality

Provider-related preterm birth happens when labor is either induced or cesarean section is performed before 37 weeks of gestational age. This type of preterm birth is mostly found in high and middle income countries, where pre-natal care and higher cesarean section birth rates are found. Severe pre-eclampsia, placental abruption, uterine rupture and fetal distress are some of the clinical maternal or fetal conditions leading to a provider initiated preterm birth.