Is it safe to use betamethasone (Betapred) as a single dose p.o. during pregnancy?/nA female in the

Fråga: Is it safe to use betamethasone (Betapred) as a single dose p.o. during pregnancy?

A female in the fifth month of pregnancy is allergic to wasps. If stung by a wasp she needs to use betamethasone orally to prevent a severe allergic reaction.

Sammanfattning: Single doses of betamethasone can be used during pregnancy, but it is recommended to be restrictive and to use betamethasone only on strict indication for these patients.

Svar: Betamethasone is a glucocorticoid that, when given systemically, has potent activity on the glucocorticoid receptor (1) The bioavailability of betamethasone per os is about 70 % (2). Betamethasone crosses the placenta to the fetus. The drug is partially metabolized by the perfused placenta to its inactive 11-ketosteroid derivative (3).

Use of corticosteroids in animals has been associated with toxic effects eg reduced fetal head circumference, reduced placental weight and reduced fetal adrenal weight. In humans multiple courses of betamethasone have been associated with lower birth weight and reduced head circumference. None of these effects has been observed in human investigations with single courses of betamethasone (3), nor has single courses of antenatal corticosteroids in humans been associated with detectable cognitive or motor deficits in long-term follow-up (4).

An increased risk of hypoglycemia in newborns exposed to betamethasone in utero has been reported. In one study adrenal suppression was greater and persisted longer in neonates receiving > 3 courses of antenatal corticosteroids versus a single course (a course of antenatal betamethasone was 12 mg given im 24 h apart or four 6 mg doses of im dexamethasone) (5). Another study did not observe adrenal suppression in nine infants whose mothers had received a mean of 4.8 treatment courses (two 12 mg doses given intramuscularly 24 hours apart and then 12 mg weekly) of betamethasone (6).

Multiple (>2) antenatal administrations of betamethasone can cause maternal adrenal suppression (7).

In the Swedish medical birth register there are 2721 children whose mothers have received glucocorticosteroides systemically during the first trimester. No increased risk of malformations compared to the general population has been observed (8).

Antenatal glucocorticoid therapy to promote fetal lung maturation for women at risk of preterm delivery is standard of care (2,4,9). Dollery C Sir, editor. Therapeutic drugs. 2nd ed. Edinburgh: Churchill Livingstone; 1999 Drugline no 12802 (year 1995) Briggs GG, Freeman RK, Yaffe SJ. Drugs in pregnancy and lactation. 6th ed. Philadelphia: Lippincott Williams & Wilkins; 2002 Guinn DA, Atkinson MW, Sullivan L, Lee M, MacGregor S, Parilla BV, Davies J et al. Single vs weekly courses of antenatal corticosteroids for women at risk for preterm delivery. A randomized controlled trial. JAMA 2001;286:1581-7. Banks BA, Cnaan A, Morgan MA, Parer JT, Merrill JD, et al. Multiple courses of antenatal corticosteroids and outcome of premature neonates. Am J Obstet Gynecol 1999;181:709-17. Terrone DA, Rinehart BK, Rhodes PG, Roberts WE, Miller RC, Martin JN Jr. Multiple courses of betamethasone to enhance fetal lung maturation do not suppress neonatal adrenal response. Am J Obstet Gynecol 1999;180(6 Pt 1):1349-53. Helal KJ, Gordon MC, Lightner CR, Barth WH Jr. Adrenal suppression induced by betamethasone in women at risk for premature delivery. Obstet Gynecol 2000;96:287-90. Källen B. Svenska medicinska födelseregistret. Socialstyrelsen. (cited ) Jobe AH, Soll RF. Choice and dose of corticosteroid for antenatal treatments. Am J Obstet Gynecol 2004;190:878-81.