High-Risk Newborn: Complications Associated with Gestational Age and Development

A preterm infant is born before 37 completed weeks of gestation, which refers to the period between conception and birth, that typically lasts for 40 weeks.

Now, the cause of preterm birth can be medically indicated, when there are maternal, fetal, and placental complications such as preeclampsia, fetal anomalies, or placenta previa.

Preterm birth can also be spontaneous, in which case the cause is often unknown, but there are certain factors that can lead to premature birth.

These include maternal factors such as extremes of age, like teenage pregnancy or age over 40 years; history of prior preterm birth; being underweight or having a poor nutritional status; use of assisted reproductive technology, like with in vitro fertilization; cervical insufficiency; substance use, including tobacco, alcohol, or illicit drugs; infections, like bacterial vaginosis or an intrauterine infection; as well as factors like late or no prenatal care; high levels of stress; long working hours, especially when there’s long periods of standing; lack of social support; and intimate partner violence.

Regardless of the cause, preterm infants are more likely to develop severe or life-threatening complications. Respiratory complications are common and are mostly related to insufficient surfactant production. This prevents the alveoli from expanding completely, resulting in hypoxia and respiratory distress syndrome. Other respiratory complications include transient tachypnea of the newborn, because of decreased absorption of fetal lung fluid and subsequent decreased gas exchange; pulmonary hemorrhage; apnea with accompanying bradycardia; as well as persistent pulmonary hypertension of the newborn, where pulmonary pressure remains high, resulting in continued shunting of blood away from the lungs through a patent ductus arteriosus.

Given these complications, preterm infants may remain on prolonged mechanical ventilation. Unfortunately, mechanical ventilation can damage the lungs over time, leading to problems like bronchopulmonary dysplasia, a lung condition that can cause chronic respiratory and developmental problems, even after the baby is discharged. Moreover, premature infants usually require prolonged oxygen therapy, increasing the risk of retinopathy of prematurity, which can result in vision loss.

Neurologic complications can occur due to the presence of fragile blood vessels, called the germinal matrix, that surround the ventricles in the brain. These vessels can easily bleed, causing an intraventricular hemorrhage, which can result in long-term complications such as cerebral palsy, and sensory or cognitive deficits.

Other problems experienced by preterm infants include impaired thermoregulation, due to their lack of subcutaneous fat, their relatively large body surface-to-weight ratio, and a decreased ability to generate heat due to absent or low levels of brown fat; hypoglycemia due to insufficient glycogen stores and increased glucose needs; infection, due to an immature immune system and lack of IgG antibodies, which are normally transferred through the placenta around 34 weeks of gestation; as well as fluid and electrolyte imbalance, anemia, and hyperbilirubinemia.

Finally, because premature infants have an underdeveloped GI system, they at risk for necrotizing enterocolitis, or NEC for short, which involves inflammation, ischemia, and necrosis of the bowel.

Clinical manifestations of prematurity will vary depending on the gestational age; however, some common ones include a disproportionately large head compared to the rest of the body, thin extremities, low muscle tone, and lack of subcutaneous fat. Skin can appear gelatinous or transparent, with visible blood vessels.

As far as behavior goes, preterm infants are often lethargic, but can also be jittery, easily stressed by external stimuli, and difficult to soothe. Other findings include temperature instability, a weak sucking reflex, and poor feeding.

Treatment typically involves supportive care in the neonatal intensive care unit, and includes close monitoring of respiratory status, and providing respiratory support. Body temperature, fluid, and glucose levels are kept within a normal range. Additionally, it’s important to prevent complications and treat them, if they do occur.