preterm baby and the small baby

Chapter 44 The preterm baby and the small baby


For the purpose of classification, management and research studies, newborn babies are considered according to their gestation, their birthweight relative to their gestation (centiles) and their actual birthweight. The midwife’s role centres on the prevention of prematurity, on preparing parents for identifying risk factors antenatally, and, in the event of preterm birth, on working with the team to support parents in the neonatal period. Please see website for more in-depth information.


Low gestational age at birth is a principal factor associated with perinatal mortality. Babies born very preterm are at particular risk of sensory, cognitive and motor dysfunction (Cooke 2005, Marlowe et al 2005). Data are now available to monitor trends, and inform care for preterm births. In 2006 in England and Wales, 7.6% of live births were preterm, 88% were born at term, and 4% were born post term, with corresponding infant mortality rates of 41.0, 1.9, and 1.5 deaths per 1000 live births (ONS 2009). Almost two-thirds of all infant deaths occurred to babies born preterm. Infant mortality was highest at the very low gestational ages.

Antenatally, gestation is estimated from the date of the last menstrual period and the woman’s normal cycle, clinical examination and early ultrasound scan measurements and uterine growth (see Chs 32 and 33).

Scoring systems estimate the neonatal gestation following delivery and neonatal units will use one, or an adaptation of one or two of the common ones. Improved accuracy of antenatal ultrasound scans has led to less reliance on these scales. The Dubowitz scale (Dubowitz et al 1970) (see Fig. 44.1) is the most widely used in the UK, and providing the baby is well and examined within a few hours of delivery, is accurate to within 2 weeks. It involves scoring the baby on neurological states as well as external criteria but may be inappropriate for use with sick or ventilated neonates.

The Ballard score (an adaptation of the Dubowitz score) is a newer system (Fig. 44.2).

These scoring systems require careful examination of the baby, looking at characteristics of appearance, reflexes and behaviour, providing an indication of whether the baby is small or premature.


Using an appropriate centile chart, the weight, head circumference and length of the baby is plotted against gestation and an assessment made of the growth. The centile chart forms an important part in providing a dynamic growth record and a link to the neonatal management (see Ch. 41).

The UK World Health Organization (WHO) growth charts (2009) are based on measurements collected by the WHO in six different countries (Fig. 44.3) (see website). These describe optimal rather than average growth and set breastfeeding as the norm, illustrating how all healthy children are expected to grow.

The preterm baby

Labour and delivery

Antenatal factors that influence fetal outcome include gestational age; steroid administration; predicted fetal weight; multiple pregnancy; sex; sepsis; presence and severity of any pathology; fetal growth restriction with abnormal Doppler flow studies; and fetal anomaly.

Preterm labour often progresses rapidly. If preterm labour is anticipated, birth should be planned in a maternity unit with the appropriate level of neonatal intensive care facilities. Transfer to another hospital is increasingly likely within a managed clinical network and should be discussed if clinically appropriate. Written information, including this possibility, should be given to all parents at booking.

All resuscitation equipment must be checked and fully functional prior to the birth. An experienced paediatrician and midwife or neonatal nurse must be present at delivery to ensure immediate and expert resuscitation. Thermal care is vital at this point, as cold stress can increase mortality and morbidity in preterm infants (see Ch. 42). The radiant heater should be turned on prior to delivery. The room temperature should be increased to 26°C.

Infants over 30 weeks’ gestation should be dried thoroughly and wrapped in a warm towel, and a hat applied. Infants under 30 weeks’ gestation should not be dried but should have their bodies placed immediately in a plastic occlusive wrap. This should not be covered with a towel as the radiant heater needs to be directly above the baby (UK Resuscitation Council 2008). This allows visualization of the chest and ease of access whilst preventing evaporative heat loss and skin damage.

Usually, preterm infants are small and fragile and are born requiring stabilization rather than active resuscitation. Some units administer surfactant prophylactically on the resuscitaire if infants require intubation under 30 weeks’ gestation. Other babies are given surfactant if they require ventilation and a diagnosis of respiratory distress syndrome is confirmed.

Common problems


The most common problems for preterm babies are respiratory disorders (discussed more fully in Chapter 45). The more preterm the baby, the more structurally and physiologically immature the respiratory system.

Respiratory distress syndrome

The incidence of respiratory distress syndrome (RDS) is inversely related to the gestational age of the baby. RDS is a developmental deficiency in surfactant synthesis accompanied by lung immaturity and hypoperfusion. Surfactant is usually produced in larger quantities between 32 and 35 weeks’ gestation and RDS is therefore rarely seen in infants beyond this gestation. Surfactant is produced by type II pneumocytes; it assists in the reduction of the surface tension of the lung and prevents complete alveolar collapse on expiration. Surfactant synthesis is reduced with hypoxaemia and acidaemia and the asphyxiated preterm infant may make such weak respiratory effort that he cannot release what little surfactant he has from the pneumocytes. The work of breathing is increased and the baby quickly becomes exhausted. The baby tries to compensate by increasing the respiratory rate and pressures. In term or more mature preterm infants, an expiratory grunt may be audible in the baby’s attempt to maintain lung volume. Intercostal and substernal recession can be quite marked – almost pulling to the backbone. There is a characteristic ‘ground glass’ appearance on chest X-ray with an air bronchogram as the air-filled major airways stand out.

Onset is before 4 hours, and the pattern of the disease gets worse over the first 24–36 hours, then stabilizes and gradually improves. Treatment is aimed at support and active intervention. Support includes maintaining oxygenation, ventilation, a normal pH and adequate perfusion, tissue oxygenation and hydration. Active intervention includes administration of exogenous surfactant and use of continuous positive airways pressure (CPAP) or other modes of ventilatory support if required.


Many preterm babies have apnoeas associated with their prematurity and require constant monitoring (Finer et al 2006). Parents need to understand the reasons for this, appreciating they resolve with maturity. Airway position is essential when nursing preterm infants, to reduce the potential for apnoeas caused by mechanical obstruction of the airway. Apnoea monitors should be removed several days prior to discharge so that parents gain confidence and do not become reliant on them. Caffeine is given as a stimulant until these apnoeas of prematurity resolve (Darnell et al 2006).

Jun 18, 2016 | Posted by in MIDWIFERY | Comments Off on preterm baby and the small baby

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