Post-term Newborn

Description

• A post-term pregnancy is one that extends beyond 42 weeks’ gestation. The post-term infant may be LGA, AGA, SGA, or dysmature, depending on placental function.

Etiology

• The cause of prolonged pregnancy is unknown. Factors associated with postmaturity include anencephaly and trisomy 16 to 18.

Pathophysiolgy

1. If the placenta continues to function well, the fetus will continue to grow, which results in an LGA infant who may manifest problems such as birth trauma and hypoglycemia.
2. If placental function decreases, the fetus may not receive adequate nutrition. The fetus will utilize its subcutaneous fat stores for energy. Wasting of subcutaneous fat occurs, resulting in fetal dysmaturity syndrome. There are three stages of fetal dysmaturity syndrome.
   • Stage 1- Chronic placental insufficiency
   1. • Dry, cracked, peeling, loose, and wrinkled skin
      • Malnourished appearance
      • Open-eyed and alert baby
   • Stage 2– Acute placental insufficiency
   1. • All features of stage 1 except point iii
      • Meconium staining
      • Perinatal depression
   • Stage 3– Subacute placental insufficiency
   1. • Findings of stage 1 and 2 except point iii
      • Green staining of skin, nails, cord, and placental membrane
      • A higher risk of fetal inrapartum or neonatal death
3. The newborn is at increased risk for developing complications related to compromised uteroplacental perfusion and hypoxia (e.g., meconium aspiration syndrome MAS)
4. Chronic intrauterine hypoxia causes increased fetal erythropoietin and red blood cell production resulting in polycythemia.
5. Post-term infants are susceptible to hypoglycemia because of the rapid use of glycogen stores.

Assessment Findings

Clinical manifestations include:

1. A long, thin newborn with wasted appearance, parchment-like skin, and meconium-stained skin, nails, and umbilical cor. Fingernails are long and lanugo is absent.
2. Meconium aspiration syndrome is manifested by fetal hypoxia, meconium staining of amniotic fluid, respiratory distress at delivery, and meconium-stained vocal cords.

Nursing Management

1. Manage meconium aspiration syndrome.

• Suction the infant’s mouth and nares while the head is on the perineum and before the first breath is taken to prevent aspiration of meconium that is in the airway.
• Once the infant is dry and on the warmer, intubate with direct tracheal suctioning.
• Perform chest physiotherapy with suctioning to remove excess meconium and secretions.
• Provide supplemental oxygen and respiratory support as needed.

2. Obtain serial blood glucose measurements.

3. Provide early feeding to prevent hypoglycemia, if not contraindicated by respiratory status.

4. Maintain skin integrity.

• Keep the skin clean and dry.
• Avoid the use of powders, creams, and lotions.
• Avoid the use of tape.