Authors' Reply

Abstract

Antenatal corticosteroid therapy and risk of osteoporosis. Br J Obsret Gynaecol1998; 105 551-555. Spencer C, Smith P, Rafla N, Weatherell R. Corticosteroids in pregnancy and osteonecrosis of the femoral head. Obster Gynecof. In press. French N, Hagan R, Evans S , Godfrey M, Newnham J. Repeated antenatal corticosteroids: size at birth and subsequent development. Am J Obsret Gynecoll999; 180: 114-121. Turnentine M, Dupras-Wilson P, Wilkins 1. A retrospective analysis of the effect of antenatal steroid administration on the incidence of respiratory distress syndrome in preterm twin pregnancies. Am J Perinarol Ardila J, LeGuennec J, Papageorgiou A. Influence of antenatal betamethasone and gender cohabitation on outcome of twin pregnancies 24 to 34 weeks of gestation. Semin Perinatall994; 18: 15-18. Garite J, Rumney P, Briggs G. A randomized placebo-controlled trial of betamethasone for the prevention of respiratory distress syndrome at 24 to 28 weeks' gestation. Am J Obstet Gynecoll992; 166: 646-65 1. 1996; 13: 351-354. Sir; We are pleased that our paper on the use of repeated courses of corticosteroids in the UK has stimulated further discussion as this is obviously an important topic for current obstetric practice. We agree with Spencer and Pakarian that adverse effects have been reported in babies whose mothers have received multiple courses of corticosteroids. The evidence, however, both from animal and human studies is conflicting. Some reports suggest a decreased incidence of adverse neonatal outcomes and others suggest harmful effects'-g. One reason for this is that observational studies are unable to separate the effect of multiple courses from either the influence of different gestational ages at delivery or the disorder for which multiple courses were prescribed. As the authors point out, women who received multiple courses of steroids are more likely to be delivered at later gestations when risk of neonatal respiratory distress and other premature complications are uncommon. However, it can also be argued that women who receive multiple courses of corticosteroids remain in an at-risk situation for longer and this in itself may be associated with a worse perinatal outcome. Without a randomised controlled trial the relative contribution of these two biases cannot be known. AUTHORS' REPLYAs our survey of practice showed, 98% of units that responded to the survey in the UK currently prescribe multiple courses of corticosteroids to some women. Whether this confers benefit, causes harm or has no effect on the condition of these babies is currently unknown and unlike Spencer and Pakarian we argue that not to do a randomised controlled trial is unethical. While waiting for the results of this trial it is not possible to recommend the number of courses of corticosteroids that may or may not be beneficial or harmful. This information can only come from a well-designed randomised controlled trial. There is no other methodology which can produce a bias-free answer.Finally Spencer and Pakarian are concerned that a t...