Management of Skin Rash After Betamethasone for Fetal Lung Maturation
Continue the betamethasone course as prescribed for fetal lung maturation, as the benefits of completing the two-dose regimen for reducing neonatal respiratory morbidity and mortality far outweigh the risks of a skin rash, which is likely a minor, self-limited adverse effect. 1, 2
Why You Should Continue Betamethasone
Betamethasone 12 mg intramuscularly in two doses, 24 hours apart, is the standard of care for fetal lung maturation and should be completed for optimal neonatal outcomes. 1, 2, 3
The medication reduces the need for respiratory support by 20% (relative risk 0.80) and severe respiratory morbidity by 33% (relative risk 0.67) in neonates delivered in the late preterm period. 1, 2
Maximum benefit occurs when delivery happens 24 hours to 7 days after administration, making completion of both doses critical. 1
Understanding the Skin Rash
Skin rash is not listed as a contraindication to betamethasone administration for fetal lung maturation in any major obstetric guidelines. 1, 2, 3
The only absolute contraindications to betamethasone for fetal lung maturation are pregestational diabetes mellitus (due to severe neonatal hypoglycemia risk) and low probability of delivery before 37 weeks. 1, 2, 3
Corticosteroids like betamethasone can cause various dermatologic reactions, but these are typically mild and self-limited compared to the critical fetal benefits. 4
Critical Context About Betamethasone in Pregnancy
Betamethasone and dexamethasone are fluorinated corticosteroids that readily cross the placenta, which is precisely why they are effective for fetal lung maturation. 4
When corticosteroids are used for maternal indications (not fetal lung maturation), prednisolone is preferred because it is 90% inactivated by the placenta, whereas betamethasone and dexamethasone cross more readily and could have greater fetal effects. 4
However, for fetal lung maturation, this placental crossing is the desired mechanism of action. 1, 2
What to Monitor
Neonatal hypoglycemia is the most common adverse effect of betamethasone, occurring more frequently with corticosteroid exposure, but 93% of cases resolve within 24 hours and are mild and self-limited. 1, 2
Blood glucose monitoring should be performed on the neonate after birth, particularly in the first 24 hours. 1
The skin rash should be monitored for signs of infection (erythema, warmth, purulent drainage), which would require separate evaluation and treatment. 4
Common Pitfalls to Avoid
Do not discontinue betamethasone based on minor side effects like skin rash when the indication is fetal lung maturation and delivery is anticipated within 7 days. 1, 2
Do not delay medically indicated delivery to complete the steroid course, but also do not withhold the second dose due to non-serious maternal side effects. 2, 3
Do not confuse the use of corticosteroids for fetal lung maturation with their use for maternal conditions—the risk-benefit calculation is entirely different. 4
Management of the Rash Itself
The rash can be managed symptomatically with topical emollients or mild topical corticosteroids if needed, without discontinuing the systemic betamethasone. 4
If the rash shows signs of infection, obtain bacterial and viral swabs and consider topical or systemic antimicrobials as appropriate. 4
Document the rash characteristics and monitor for progression, but this should not alter the betamethasone dosing schedule for fetal lung maturation. 4