What are the guidelines for using steroids during pregnancy?

Steroid Use During Pregnancy

Steroids are safe and indicated during pregnancy for specific maternal conditions and fetal lung maturation, with the choice of steroid type, timing, and dose depending critically on the clinical indication—betamethasone or dexamethasone for fetal lung maturation between 24-34 weeks, and prednisolone or methylprednisolone (not betamethasone/dexamethasone) for maternal conditions. 1

Antenatal Corticosteroids for Fetal Lung Maturation

Primary Indications and Timing

• Administer betamethasone 12 mg intramuscularly twice, 24 hours apart, to pregnant women between 24+0 and 33+6 weeks gestation who are at high risk of preterm delivery within 7 days. 1, 2, 3

• Specific high-risk criteria include: preterm labor with cervical dilation ≥3 cm or cervical thinning ≥75%, spontaneous rupture of membranes, or planned preterm delivery for maternal/fetal indications (preeclampsia, fetal growth restriction, oligohydramnios). 1

• Even if delivery is expected within 18 hours, still administer corticosteroids—benefits occur even with a single dose. 4, 3

• Optimal benefit occurs when delivery happens 18-72 hours after administration, but benefits extend up to 7 days. 4

Late Preterm Period (34-36 Weeks)

• Consider betamethasone for women at 34+0 to 36+6 weeks only if there is high probability of delivery within 7 days and no prior course was given. 1, 2

• The Society for Maternal-Fetal Medicine emphasizes this should be selective—the ALPS trial showed only 16.4% of treated women delivered preterm, meaning most received unnecessary treatment. 5

• Diabetes mellitus is an absolute contraindication for late preterm steroids due to significant risk of worsening neonatal hypoglycemia. 1

Rescue or Repeat Courses

• One single additional rescue course may be given if the initial course was administered >14 days ago, gestational age remains <34 weeks, and delivery is now imminent. 1, 2, 3

• Rescue courses can be given as early as 7 days from the prior dose if clinically indicated. 2

• Avoid multiple repeat courses beyond one additional dose—they reduce infant birthweight and head circumference without additional benefit. 1

What NOT to Do

• Do not give corticosteroids routinely before elective cesarean delivery at term—there is no benefit and long-term safety is unknown. 1, 3

• Do not administer steroids "just in case" to women with low probability of preterm delivery before 37 weeks. 1, 4

Steroids for Maternal Medical Conditions

Critical Distinction in Steroid Selection

This is a common and dangerous pitfall: Betamethasone and dexamethasone cross the placenta almost completely (~100% placental passage) and are used specifically to treat the fetus. 5 For maternal conditions, you must use prednisolone, methylprednisolone, or hydrocortisone—these are metabolized by the placenta so only ~10% reaches the fetus. 5, 1

Specific Maternal Indications

• Continue prednisolone, azathioprine, cyclosporine, and tacrolimus in pregnant transplant recipients—do not stop these medications. 5, 1

• Mycophenolate mofetil must be stopped at least 12 weeks before conception due to severe teratogenicity (49% miscarriage rate, 23% structural anomalies). 5, 1

• Short courses of oral corticosteroids (prednisolone or methylprednisolone) can be used after the first trimester for severe asthma exacerbations or other conditions threatening maternal health. 1

Intranasal and Topical Corticosteroids

• Modern nasal corticosteroids (budesonide, fluticasone, mometasone) are safe at recommended doses throughout pregnancy. 1, 6, 7

• If initiating new therapy during pregnancy, budesonide intranasal is preferred due to more extensive human safety data (FDA category B). 6, 7

• Low to moderate potency topical corticosteroids are safe for limited body surface areas. 7

• Avoid potent to very potent topical corticosteroids over large body surface areas—they may increase risk of low birth weight. 7

Chemotherapy-Related Nausea

• Methylprednisolone or prednisolone (not betamethasone/dexamethasone) can be used for chemotherapy-induced nausea after 10 weeks gestation. 5

• Before 10 weeks gestation, glucocorticosteroids increase oral cleft incidence and should be avoided if possible. 5

Maternal and Fetal Risks

Maternal Side Effects

• Hyperglycemia and potential gestational diabetes—screen all women on glucocorticoids for gestational diabetes. 1, 6

• Hypertension and increased preeclampsia risk, particularly with cyclosporine and tacrolimus. 1

• Adrenal suppression with prolonged use (>5 mg prednisolone daily for >3 weeks)—consider stress-dose steroids at delivery. 1

Fetal/Neonatal Risks

• Slight increase in cleft lip with or without cleft palate with first-trimester exposure, though recent data are more reassuring than older studies. 1, 8, 9

• The FDA labels for both prednisone and betamethasone confirm increased incidence of cleft palate in animal studies. 8, 9

• Neonatal hypoglycemia, especially with late preterm steroids and when betamethasone is administered close to delivery time. 1, 9

• Potential for increased preterm birth and low birth weight with prolonged maternal steroid use. 1

Long-Term Neurodevelopmental Concerns

• The Society for Maternal-Fetal Medicine acknowledges that long-term neurodevelopmental risks of antenatal corticosteroids, particularly in the late preterm period, remain uncertain. 5

• Patients must be counseled that while short-term data are reassuring, long-term safety data beyond 6 years are lacking. 5

Breastfeeding Compatibility

• Oral and topical corticosteroids are compatible with breastfeeding—very little enters breast milk. 1, 7, 10

• Prednisone or non-fluorinated steroids <20 mg per day are specifically compatible. 1

• The FDA label notes that systemically administered corticosteroids appear in human milk and caution should be exercised, but clinical practice guidelines are more permissive. 8, 9

Dosing Specifics

For Fetal Lung Maturation

• Betamethasone: 12 mg IM twice, 24 hours apart (preferred in US guidelines). 1, 4, 2, 3
• Dexamethasone: 6 mg IM four times, 12 hours apart, OR 12 mg IM twice, 24 hours apart (alternative). 4, 3

For Maternal Conditions

• Use the lowest effective dose of prednisolone or methylprednisolone. 1
• Monitor closely if doses exceed 5 mg prednisolone daily for >3 weeks. 1

Critical Clinical Pearls

• Never use betamethasone or dexamethasone for maternal conditions—their near-complete placental passage exposes the fetus unnecessarily. 5, 1

• The greatest teratogenic risk is first-trimester exposure, particularly before 10 weeks when the palate is forming. 5, 1

• Twin pregnancies should receive the same indications and doses as singletons, but reserve treatment for truly high-risk situations with delivery expected within 7 days. 3

• Maternal diabetes is NOT a contraindication for antenatal corticosteroids at <34 weeks, but IS an absolute contraindication for late preterm steroids (34-36 weeks). 1, 3