NCLEX Review Guide: Maternal Newborn Medications

Betamethasone (Celestone) and Dexamethasone

• Betamethasone and dexamethasone are corticosteroids administered to pregnant women at risk for preterm delivery between 24 and 34 weeks gestation. These medications cross the placenta and accelerate fetal lung maturity by stimulating the production of surfactant, which reduces the risk of respiratory distress syndrome (RDS) in premature infants.
• The standard regimen for betamethasone is two 12mg intramuscular doses given 24 hours apart, while dexamethasone is typically administered as four 6mg intramuscular doses given 12 hours apart. Both medications demonstrate maximum effectiveness when delivered 24 hours to 7 days before birth.

When to Administer Antenatal Corticosteroids

• Antenatal corticosteroids are indicated when there is a risk of preterm delivery within 7 days, including conditions such as preterm labor, preterm premature rupture of membranes (PPROM), antepartum hemorrhage, or medically indicated preterm birth for maternal or fetal conditions.
• Administration should be considered for women between 24 0/7 and 33 6/7 weeks of gestation, with possible benefits extending to those at 23 0/7 to 23 6/7 weeks after appropriate counseling about neonatal outcomes.

Mechanism of Action

• Betamethasone and dexamethasone cross the placenta in their active form because they are not significantly metabolized by the placental enzyme 11β-hydroxysteroid dehydrogenase, unlike other corticosteroids such as prednisone.
• These medications stimulate the production of surfactant proteins and phospholipids in type II pneumocytes of the fetal lungs. Surfactant reduces alveolar surface tension, preventing alveolar collapse during expiration and improving lung compliance in the newborn.

Betamethasone vs. Dexamethasone Comparison

Administration Protocol

1. Verify the correct medication, dose, and timing according to the prescription.
2. Confirm gestational age is within the recommended window (typically 24-34 weeks).
3. Assess maternal vital signs and blood glucose prior to administration.
4. Administer betamethasone or dexamethasone via deep intramuscular injection using appropriate technique.
5. Document the administration time, dose, site, and maternal response.
6. Schedule and ensure administration of the second dose (and subsequent doses for dexamethasone) at the correct intervals.
7. Monitor maternal blood glucose levels, especially in women with diabetes or gestational diabetes.

Maternal and Fetal Effects

• Maternal side effects may include transient hyperglycemia, increased susceptibility to infection, fluid retention, and mood changes. These effects are generally mild and self-limiting given the short course of therapy.
• There are no absolute contraindications to antenatal corticosteroids when indicated for fetal lung maturity, as the benefits typically outweigh the risks. Even in conditions such as maternal diabetes, chorioamnionitis, or hypertensive disorders, these medications can be administered with appropriate monitoring and management.

NCLEX Preparation for Antenatal Corticosteroids

• Focus on understanding the timing of administration (24-34 weeks gestation) and the optimal window of effectiveness (24 hours to 7 days before delivery).
• Know the specific dosing regimens for both medications: betamethasone (two 12mg doses 24 hours apart) and dexamethasone (four 6mg doses 12 hours apart).

Self-Assessment