Is Celestone (betamethasone) injection safe to use during the second trimester of pregnancy?

Celestone (Betamethasone) Injection in Second Trimester

Celestone (betamethasone) injection is safe and recommended for use in the second trimester of pregnancy when there is imminent risk of preterm delivery, specifically for fetal lung maturation in pregnancies at risk of delivery before 36 weeks of gestation. 1

Primary Indication and Safety Profile

• Antenatal corticosteroids, including betamethasone, are specifically recommended before preterm delivery (before 36 weeks) to reduce fetal morbidity and mortality associated with respiratory distress syndrome. 1

• The FDA drug label confirms that corticosteroids have been shown to be teratogenic in animal studies when given at doses equivalent to human doses, but emphasizes that use during pregnancy may be justified if potential benefits outweigh risks. 2

• Before cardiac surgery or anticipated preterm delivery in the second trimester, a full course of corticosteroids should be administered to the mother whenever possible. 1

Specific Timing and Dosing Considerations

• The standard clinical regimen consists of 2 intramuscular doses of betamethasone (typically 12 mg each) administered 24 hours apart. 3, 4

• Recent research suggests that a 12-hour dosing interval may be equivalent to the 24-hour interval for RDS prevention, though this was associated with increased necrotizing enterocolitis risk (6.2% vs 0%, P=.03). 5

• Treatment should ideally be completed at least 48 hours before anticipated delivery for maximum fetal lung maturation benefit. 3

Gestational Age-Specific Recommendations

• For deliveries anticipated between 24-34 weeks gestation: Betamethasone is standard of care with strong evidence for reducing respiratory distress syndrome (RDS reduced from 14.4% to 8.8%, adjusted RR 0.62,95% CI 0.45-0.86). 4

• For deliveries anticipated between 34 0/7 and 36 6/7 weeks: Betamethasone may be considered in singleton pregnancies at imminent risk of delivery within 7 days, though this primarily reduces transient tachypnea of the newborn (a self-limited condition) rather than severe RDS. 6

• Beyond 37 weeks gestation: Betamethasone is not indicated as fetal lung maturation is typically complete. 6

Maternal Conditions Requiring Special Consideration

Cancer Treatment During Pregnancy

• When chemotherapy is urgently needed during the second trimester and preterm delivery is anticipated, betamethasone should be administered before delivery to reduce neonatal respiratory complications. 1

• Chemotherapy administration in the second trimester carries lower malformation risk than first trimester exposure, but increases risk of preterm delivery, making antenatal corticosteroids particularly relevant. 1

Cardiovascular Disease

• In pregnant women with cardiovascular disease requiring cardiac surgery in the second trimester, betamethasone should be administered before the procedure whenever possible. 1

Known Adverse Effects and Monitoring

Neonatal Effects

• Neonatal hypoglycemia has been reported after antenatal betamethasone administration, especially in preterm, low birth weight infants, and when administered close to delivery time. 2

• Infants born to mothers receiving corticosteroids should be carefully observed for signs of hypoadrenalism. 2

• Recent animal research indicates that betamethasone phosphate (the rapidly-acting component) may be associated with lower birthweights and greater fetal hypothalamic-pituitary-adrenal axis suppression compared to betamethasone acetate alone. 7

Maternal Considerations

• Systemically administered corticosteroids appear in human milk and could suppress infant growth or interfere with endogenous corticosteroid production. 2

• Caution should be exercised when administering to nursing women, though the benefits for preterm neonatal outcomes typically outweigh these concerns. 2

Critical Clinical Pitfalls to Avoid

• Do not administer betamethasone "just in case" to women at low risk of imminent preterm delivery (>7 days from anticipated delivery), as this exposes the fetus to unnecessary corticosteroid effects without proven benefit. 6

• Avoid multiple courses of betamethasone, as repeated exposure increases risks without clear additional benefit and may lead to "treatment creep" beyond evidence-based indications. 6

• Do not assume that betamethasone administration eliminates all prematurity-related complications—late preterm infants may still require intensive care for non-respiratory morbidities even after steroid treatment. 6

• The greatest benefit occurs when delivery happens 24 hours to 7 days after treatment completion; administration too close to delivery or too far in advance reduces efficacy. 3, 5

Evidence Quality and Strength

• The recommendation for betamethasone use in the second trimester for anticipated preterm delivery is based on over 50 years of clinical evidence, beginning with the landmark Auckland Steroid Trial. 4

• Male fetuses appear to derive greater benefit from betamethasone than female fetuses (greater reduction in RDS), though treatment is recommended regardless of fetal sex. 4

• The evidence is strongest for deliveries between 24-34 weeks gestation, with more limited and controversial data for late preterm (34-36 6/7 weeks) administration. 6