Low Risk Neonatal Nurse Exam

This chapter links common maternal illnesses to the newborn problems they cause, so you can anticipate needs before the first assessment.

Maternal glucose crosses the placenta, but insulin does not. When maternal glucose runs high, the fetal pancreas responds with extra insulin. Fetal hyperinsulinism drives growth of fat and organs (macrosomia), increases oxygen use and delays surfactant production. When the cord is clamped, the glucose supply stops abruptly but the high insulin continues, so blood glucose falls, usually within the first 1 to 2 hours.

Problems of the infant of a diabetic mother (IDM) include hypoglycemia, macrosomia and birth injury (shoulder dystocia, brachial plexus injury, clavicle fracture), respiratory distress even near term, polycythemia, hyperbilirubinemia, hypocalcemia, hypomagnesemia and hypertrophic cardiomyopathy. Poorly controlled pregestational diabetes also raises the risk of heart defects, neural tube defects, caudal regression syndrome and small left colon syndrome; gestational diabetes does not raise the anomaly rate in the same way.

Nursing care: begin glucose screening per protocol (often before the second feed or within the first 1 to 2 hours), feed early, keep the infant warm, examine for birth injury and murmur, and watch for jitteriness, tachypnea and jaundice.

Chronic hypertension, gestational hypertension, preeclampsia and HELLP syndrome (hemolysis, elevated liver enzymes, low platelets) reduce placental blood flow. The infant may be growth restricted and preterm by indicated delivery, and may have neutropenia and thrombocytopenia in the first days, plus hypoglycemia and polycythemia.

Magnesium sulfate is given to prevent eclamptic seizures and, before 32 weeks, for fetal neuroprotection. It crosses the placenta freely. A newborn with high magnesium may show hypotonia, weak cry, decreased reflexes, respiratory depression or apnea, poor suck and delayed meconium passage. Effects fade as the kidneys excrete the magnesium over the first days.

In maternal Graves disease, thyroid-stimulating antibodies (TRAb) cross the placenta and can cause neonatal hyperthyroidism even after maternal thyroid surgery or radioiodine. Maternal antithyroid drugs also cross and may mask it for several days, so signs can appear late in the first week or beyond: tachycardia, irritability, sweating, poor weight gain despite good intake, goiter and sometimes heart failure. These infants need thyroid testing and follow-up per protocol.

Untreated maternal hypothyroidism can affect fetal brain development. The infant's own thyroid function is checked by newborn screening.

Maternal anti-Ro (SSA) and anti-La (SSB) antibodies, seen with lupus and Sjogren syndrome, can damage the fetal conduction system and cause congenital complete heart block: a slow, fixed heart rate (often about 50 to 80) that does not rise with stimulation. Neonatal lupus can also cause an annular rash around the eyes, thrombocytopenia and elevated liver enzymes. The nurse obtains an ECG per order, monitors perfusion and anticipates cardiology consultation and possible transfer for pacing.

Maternal obesity raises the risk of gestational diabetes, preeclampsia, cesarean birth, macrosomia, birth injury and neural tube and heart defects, and makes prenatal ultrasound less reliable.

In maternal immune thrombocytopenia (ITP), IgG antiplatelet antibodies cross the placenta and may lower the infant's platelet count. The infant's count often falls further over the first days, with the lowest point commonly around days 2 to 5, so a platelet count is checked at birth and repeated per protocol. Compare this with neonatal alloimmune thrombocytopenia (NAIT), in which the mother's platelet count is normal and the infant may have severe thrombocytopenia and intracranial hemorrhage (Section 6).

Group B streptococcus (GBS). Intrapartum prophylaxis is adequate only when penicillin G, ampicillin or cefazolin is given at least 4 hours before birth. Clindamycin and vancomycin, used for severe penicillin allergy, do not count as adequate for newborn risk assessment, and neither does any antibiotic given less than 4 hours before birth. Other early-onset sepsis risk factors are rupture of membranes 18 hours or longer, maternal fever, intraamniotic infection, preterm birth and a previous infant with GBS disease.

Hepatitis B. If the mother is HBsAg positive, give hepatitis B vaccine and hepatitis B immune globulin (HBIG) within 12 hours of birth in separate thighs. If maternal status is unknown, give the vaccine within 12 hours and test the mother right away; infants under 2,000 g also receive HBIG within 12 hours, while larger infants receive it within 7 days if the mother tests positive. For infants under 2,000 g the birth dose does not count toward the series. Breastfeeding is encouraged.

HIV. Bathe the infant to remove maternal blood and secretions before any injection, and start antiretroviral prophylaxis (such as zidovudine, alone or combined based on maternal viral load) as soon as possible, ideally within 6 hours. In the United States breastfeeding has traditionally not been recommended; current guidance supports shared decision-making with an HIV specialist for mothers with a sustained undetectable viral load on therapy.

Hepatitis C. Vertical transmission is uncommon. The infant is tested with HCV RNA at about 2 to 6 months per current public health guidance. Breastfeeding is allowed unless nipples are cracked or bleeding.

Syphilis. Congenital syphilis is rising and preventable. Infant evaluation compares the infant's nontreponemal titer (RPR or VDRL) with the mother's; an infant titer fourfold or more higher suggests congenital infection. Signs include persistent rhinitis ("snuffles"), hepatosplenomegaly, rash on palms and soles, jaundice, anemia and pseudoparalysis of a limb. Treatment is penicillin G per protocol.

Herpes simplex virus (HSV). Risk is highest with a first (primary) maternal genital infection near delivery and lowest with a recurrent outbreak. An exposed infant is placed on contact precautions and evaluated per the AAP approach. Infection may involve skin, eyes and mouth, the CNS, or be disseminated, often in the second week of life, and can look like bacterial sepsis.

Intraamniotic infection and maternal fever. Intraamniotic infection (chorioamnionitis) is suspected with maternal fever plus findings such as fetal tachycardia, maternal leukocytosis or purulent fluid. The infant needs evaluation for early-onset sepsis per unit protocol. Maternal fever from epidural analgesia can mimic infection, which is one reason many units use a sepsis risk calculator or serial exams for infants 35 weeks or more.

Common Trap: A mother received clindamycin for GBS because of a penicillin allergy 6 hours before birth. This is not adequate prophylaxis for newborn risk assessment, even though it was given more than 4 hours before birth.

Clinical Scenario: A 3,150 g term infant is admitted for observation, and the mother's HBsAg result is not on the chart. The nurse should give hepatitis B vaccine within 12 hours of birth and make sure the mother's HBsAg test is sent immediately. If the result is positive, HBIG is given as soon as possible and within 7 days. Had the infant weighed under 2,000 g, HBIG would also be given within 12 hours without waiting.

• Fetal hyperinsulinism explains most IDM problems: hypoglycemia, macrosomia, delayed lung maturity, polycythemia and cardiomyopathy.
• Magnesium exposure can cause hypotonia, respiratory depression and poor suck; monitor breathing and feed cautiously.
• Maternal anti-Ro/anti-La antibodies cause congenital heart block with a fixed slow heart rate.
• Adequate GBS prophylaxis means penicillin, ampicillin or cefazolin at least 4 hours before birth.
• HBsAg-positive mother: vaccine plus HBIG within 12 hours; HIV exposure: bathe first, start antiretroviral prophylaxis within hours.