Neonatal Nurse Practitioner Exam

This chapter covers maternal infections that change newborn management, then prescription, over-the-counter and illicit drug exposures and their expected neonatal findings.

Universal screening for GBS colonization by vaginal-rectal culture is performed at 36 0/7 to 37 6/7 weeks. Intrapartum antibiotic prophylaxis (IAP) is indicated for a positive screen, GBS bacteriuria at any time in the pregnancy, a prior infant with invasive GBS disease, or unknown status with any of the following: delivery before 37 weeks, rupture of membranes 18 hours or more, intrapartum temperature 38.0 °C or higher, or a positive intrapartum nucleic acid test.

For newborn risk assessment, IAP is considered adequate only when penicillin, ampicillin or cefazolin was given 4 hours or more before delivery. Clindamycin and vancomycin, used for severe penicillin allergy, are not counted as adequate for this purpose.

Intraamniotic infection (chorioamnionitis) is a major risk factor for early-onset sepsis. The clinical diagnosis rests on maternal fever with supporting findings such as maternal leukocytosis, purulent cervical drainage or fetal tachycardia. The NNP applies the unit's early-onset sepsis approach (categorical algorithm, multivariable sepsis risk calculator for infants at 35 weeks or more, or enhanced clinical observation). Preterm infants born to mothers with intraamniotic infection generally receive blood culture and empiric antibiotics, while preterm infants delivered by cesarean for maternal indications without labor or rupture of membranes are low risk.

Maternal Infections and Neonatal Management Principles

HSV: the risk of neonatal HSV is much higher with a first-episode (primary) maternal infection at delivery than with a recurrence, because the mother has not yet made protective IgG. Cesarean delivery is recommended when genital lesions or prodromal symptoms are present at labor, and maternal acyclovir or valacyclovir suppression from about 36 weeks reduces recurrences. For an asymptomatic infant delivered vaginally or by cesarean through active lesions, the NNP obtains surface swabs and blood PCR at about 24 hours of age; if the maternal episode is first-episode, CSF PCR, serum ALT and empiric IV acyclovir are added while results are pending.

HIV: a mother with sustained viral suppression on antiretroviral therapy has a very low transmission risk. Maternal intravenous zidovudine during labor is recommended when viral load is above about 1,000 copies/mL or unknown near delivery. Infants at low risk receive zidovudine prophylaxis; infants at higher risk (no maternal therapy, detectable viral load near delivery, acute maternal infection) receive multidrug presumptive therapy. Infant diagnosis uses HIV nucleic acid tests (DNA or RNA PCR), not antibody tests, because maternal antibody persists.

Hepatitis B: the infant of an HBsAg-positive mother receives hepatitis B vaccine and hepatitis B immune globulin (HBIG) within 12 hours of birth, regardless of weight. If maternal status is unknown, give vaccine within 12 hours; infants under 2,000 g also receive HBIG within 12 hours, while infants at 2,000 g or more may receive HBIG within 7 days if the mother tests positive. Breastfeeding is encouraged.

Hepatitis C: vertical transmission occurs in a minority of exposed infants, higher with HIV coinfection. Breastfeeding is permitted unless nipples are cracked or bleeding. Infants are tested with HCV RNA in early infancy, or with antibody testing after maternal antibody has cleared, per current guidance.

Syphilis: maternal treatment is adequate when a stage-appropriate penicillin regimen was started at least 30 days before delivery and the mother had an appropriate titer response. The NNP compares maternal and infant nontreponemal titers (RPR or VDRL) drawn on infant serum, not cord blood. An infant titer fourfold or higher than the mother's, or an abnormal examination, makes congenital syphilis proven or highly probable and calls for a full evaluation and 10 days of aqueous penicillin G.

CMV: the most common congenital infection. Primary maternal infection carries the highest transmission risk, but reactivation or reinfection causes many cases. Findings include SGA, microcephaly, periventricular calcifications, hepatosplenomegaly, petechiae and sensorineural hearing loss.

Zika virus: congenital Zika syndrome includes severe microcephaly with partially collapsed skull, subcortical calcifications, ocular abnormalities, congenital contractures and hypertonia. Evaluate exposed infants with examination, head imaging, eye examination, hearing screening and laboratory testing per public health guidance.

Selected Fetal and Neonatal Drug Effects

SSRI neonatal adaptation syndrome appears within the first days as jitteriness, irritability, tachypnea, poor feeding and occasionally hypoglycemia. It is self-limited and managed supportively; the NNP should not stop breastfeeding because of it.

Magnesium sulfate is used for seizure prophylaxis in preeclampsia and for fetal neuroprotection before 32 weeks, where it reduces the risk of cerebral palsy. Newborn effects reflect hypermagnesemia: hypotonia, weak cry, respiratory depression or apnea, decreased gut motility with delayed stooling, and rarely hypotension. Most infants need only observation and supportive care. Magnesium and aminoglycosides both impair neuromuscular transmission, so a hypotonic, hypermagnesemic infant on gentamicin deserves close respiratory monitoring.

Antenatal corticosteroids are among the most effective perinatal interventions. A course of betamethasone (12 mg IM, two doses 24 hours apart) or dexamethasone (6 mg IM every 12 hours for four doses) is recommended from 24 0/7 to 33 6/7 weeks when preterm delivery within 7 days is likely, may be considered from 22 0/7 weeks after counseling, and may be given at 34 0/7 to 36 6/7 weeks in selected women who have not already received a course. Benefits include lower rates of RDS, IVH, NEC and death. The greatest benefit occurs from 24 hours after the first dose to about 7 days. Late preterm exposure increases neonatal hypoglycemia risk.

Exam Tip: When a stem asks what single antenatal intervention most improves survival and reduces IVH and RDS in a 26-week fetus, the best answer is antenatal corticosteroids. Magnesium sulfate is the answer when the outcome named is cerebral palsy.

Substance Exposure and Expected Newborn Findings

Opioid withdrawal timing depends on half-life: short-acting opioids such as heroin or oxycodone typically produce signs within about 24 to 48 hours; buprenorphine at about 36 to 60 hours; methadone at about 48 to 72 hours and occasionally later. Signs include tremor, high-pitched cry, hypertonia, poor sleep, feeding difficulty, loose stools, sweating, sneezing and tachypnea. Management begins with nonpharmacologic care (rooming-in, holding, breastfeeding when appropriate, low stimulation) with function-based assessment; medication is added when function cannot be maintained. Breastfeeding is supported for mothers in stable methadone or buprenorphine treatment who are not using illicit substances.

Common Trap: Naloxone for a depressed newborn of an opioid-dependent mother can precipitate acute withdrawal and seizures. Support ventilation instead; naloxone is not part of routine delivery room resuscitation.

IAP is adequate for newborn risk assessment only with penicillin, ampicillin or cefazolin given 4 hours or more before delivery.

Primary maternal HSV near delivery carries the highest transmission risk; follow an exposure-based evaluation.

ACE inhibitors and ARBs are fetotoxic later in pregnancy; NSAIDs cause oligohydramnios and ductal constriction.

Antenatal steroids reduce RDS, IVH, NEC and death; magnesium before 32 weeks reduces cerebral palsy.

Opioid withdrawal onset is earlier with short-acting opioids and later with methadone.