Pregnancy, birth and the newborn

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17 Pregnancy, birth and the newborn

Introduction

The newborn period is a time to celebrate and to support and advise families about the health of their new baby. However, illness may present during this time, and this poses a particular challenge to the family and doctors involved.

The foundations of a child’s health are laid in pregnancy. Many diseases in childhood are linked to the antenatal health of the mother and the wider family. Birth may similarly affect a child’s long-term health, particularly:

• Infants with congenital anomalies (see Chapter 18)

• Premature infants (less than 37 completed weeks of gestation)

• Infants born small for gestational age (see also Chapter 12, p. 147).

Infants in these categories have greatly increased neonatal infant mortality and morbidity in childhood. Additionally, there is a relationship between low birth weight and increased risk of premature cardiovascular disease, diabetes and mortality in adult life – the Barker hypothesis.

The healthy pregnancy

Antenatal care is important. It provides support and reassurance to the mother and her partner, and may detect early signs of ill health in either mother or child. Attendance for antenatal care is associated with improved pregnancy outcomes, whereas late presentation (‘unbooked pregnancy’) is associated with higher rates of maternal morbidity (e.g. anaemia, hypertension) and fetal morbidity (low birth weight) and mortality (stillbirth and early neonatal death).

See Table 17.1 for advice that can be given to women planning pregnancy.

Table 17.1 Health advice for women planning pregnancy

Advice	Reasoning
Folic acid prior to conception	Prevention of neural tube defects
Avoid excess alcohol	Prevention of fetal alcohol syndrome
Avoid excess alcohol	Improves maternal health
Stop or decrease smoking	Reduces the risk of premature birth, intrauterine growth retardation (see Chapter 12, p. 147) and respiratory disease in childhood
Avoid unpasteurized dairy products	Reduce risk of congenital Listeria
Avoid handling cat litter	Reduces risk of toxoplasmosis
Rubella immunization if not immune	Avoidance of congenital rubella (see Chapter 16, p. 235)

Antenatal screening

Pregnant women are screened for a range of maternal and fetal problems:

• Dating scan at ‘booking’ to confirm gestation

• Blood group and antibody screen for potential haemolytic disorders, e.g. rhesus incompatibility (see Chapter 7, p. 60)

• Rubella antibodies

• Hepatitis B, syphilis and HIV serology

• Alpha-fetoprotein for neural tube defects

• Triple test for Down syndrome (alpha-fetoprotein, human chorionic gonadotrophin, unconjugated oestriol) at 16 weeks’ gestation. Ultrasound scanning to detect increased nuchal translucency (11–14 weeks’ gestation) is being progressively introduced throughout the UK as a more sensitive test for detection of increased risk of Down syndrome and other congenital disorders

• Fetal anomaly scan at 18–20 weeks’ gestation (see Box 17.1).

Ultrasound is also useful for monitoring fetal health and growth, potential abnormalities and amniotic fluid volumes in later pregnancy.

Some women are at higher risk of having problems in pregnancy and may be offered additional tests, e.g. amniocentesis for women over 35 years. Pregnancies at increased risk of abnormality include:

Table 17.2 Medication with recognized teratogenic effects on the fetus

Maternal medication	Teratogenic effect on fetus
Carbamazepine	Neural tube defects
Lithium	Congenital heart disease
Phenytoin	Fetal hydantoin syndrome
Propylthiouracil	Hypothyroidism
Tetracycline	Enamel hypoplasia of the teeth
Valproate	Neural tube defects valproate embryopathy
Warfarin	Microcephaly, nasal hypoplasia

Birth

Neonatal resuscitation

Most infants do not require resuscitation. Some may not establish effective respiration and require help. Infant resuscitation is covered in Appendix I. The resuscitation routine is altered if the baby is premature or if the amniotic fluid is stained with meconium.

The Apgar score

The Apgar score (named after Virginia Apgar) is calculated at 1 and 5 minutes of life. It gives an indication of the condition of the baby at this time and provides a standard way of documenting the health of the baby in the first few minutes of life. Many parents know about this score. It is sometimes necessary to reassure worried parents that a score of less than 10 at 1 or 5 minutes is not an indicator for a lifetime of under-achievement! (see Table 17.3).

Table 17.3 Calculating the Apgar score

Adaptation to extra-uterine life

The process of delivery, temperature change and the clamping of the umbilical cord results in gasping and the removal of the remaining lung fluid. The pulmonary vascular resistance falls and pulmonary blood flow increases. The increased left atrial filling closes the foramen ovale and oxygenated blood flowing through the ductus arteriosus causes its eventual closure (see also Chapter 9, pp. 91–93).

The newborn

Examination of the newborn

Every newborn baby is examined soon after birth – usually within the first 24 hours of life. This examination is in part a screening tool but is also an opportunity for parents to raise concerns they might have about their child.

The objectives of the examination are to identify any congenital anomaly not identified by antenatal screening. The most important of these are structural heart lesions (see Chapter 9, pp. 91–95), congenital cataracts and other eye disease detectable through absence of the ‘red reflex’ (see Chapter 14, p. 210), and developmental dysplasia of the hip (see Chapter 6, p. 49) (see Figure 17.1).

Figure 17.1 The post-natal examination.

Birth injuries

Deliveries following an obstructed labour or malpresentation and instrumental deliveries can cause injury. These include nerve palsies, soft-tissue injuries and fractures. The newborn examination will identify these.

Feeding

Breast-feeding

Breast milk is the best food for babies, irrespective of gestation. Exclusive breast-feeding is recommended for the first 4 to 6 months of life. Breast milk is nutritionally complete and ideal for feeding on demand. The benefits of breast milk include anti-infective properties, low allergenicity, improved digestion, fewer episodes of gastroenteritis and a reduced incidence of necrotizing enterocolitis in premature infants. There is some epidemiological evidence for improved cognitive function. Supplements may need to be added to breast milk to optimize growth in preterm infants.

The benefits for mothers who breast-feed are the promotion of attachment with their child, a reduced risk of breast cancer, and possibly a decreased risk of osteoporosis. Mothers who breast-feed show a quicker return to their pre-pregnancy weight.

Whey and casein are the main proteins in breast milk. Whey forms a soft yoghurt-like curd in the stomach which produces a fine texture for digestion by enzymes. Gastric emptying is rapid. Breast milk comprises 60% whey.

Casein forms a firmer curd in the stomach, similar to cottage cheese. This is digested more slowly and gastric emptying is slower. Breast milk comprises 40% casein.

There are very few reasons not to breast-feed a baby. These may include:

• Maternal illness

• Infant illness

• Maternal medications.

Formula milks

Infant formulas have been developed to be either whey dominant or casein dominant. Standard formula comprises 60% whey and 40% casein (whey dominant).

These formulas are recommended for demand-feeding patterns similar to breast-fed infants. They are formulated for bottle-feeding from birth or when moving from breast-feeding, due to the similarity with breast milk composition. Standard formulas are suitable up to 12 months of age. It is important to remember that formula feed needs to be made up in a sterile fashion. The teat needs to suit the baby, and the temperature needs to be correct.

For more information on infant feeding and weaning, see Chapter 13, p. 160)

Preventing illness

Vitamin K

Babies have a limited ability to synthesize vitamin K. This persists for the first 3 months of life. In addition, during early infancy when fed entirely on milk, babies have very little supply of vitamin K, especially if exclusively breast-fed. A very small number of babies suffer bleeding due to vitamin K deficiency. This is called ‘haemorrhagic disease of the newborn’.

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