Antenatal glucocorticoids: where are we after forty years?

Since their introduction more than forty years ago, antenatal glucocorticoids have become a cornerstone in the management of preterm birth and have been responsible for substantial reductions in neonatal mortality and morbidity. Clinical trials conducted over the past decade have shown that these benefits may be increased further through administration of repeat doses of antenatal glucocorticoids in women at ongoing risk of preterm and in those undergoing elective cesarean at term. At the same time, a growing body of experimental animal evidence and observational data in humans has linked fetal overexposure to maternal glucocorticoids with increased risk of cardiovascular, metabolic and other disorders in later life. Despite these concerns, and somewhat surprisingly, there has been little evidence to date from randomized trials of longer-term harm from clinical doses of synthetic glucocorticoids. However, with wider clinical application of antenatal glucocorticoid therapy there has been greater need to consider the potential for later adverse effects. This paper reviews current evidence for the short- and long-term health effects of antenatal glucocorticoids and discusses the apparent discrepancy between data from randomized clinical trials and other studies.

The short term fetal cardiovascular effects of corticosteroids used in obstetrics

Background: Corticosteroids are widely used in obstetrics due to their striking effect on perinatal morbidity and mortality of premature neonates. Despite this, relatively few studies have explored short term fetal effects of corticosteroids as measured by ultrasound. Objectives: 1) To present a literature review of short term fetal cardiovascular effects of corticosteroids 2) To describe the protocol of a current observational study (SUPER-A*STEROID) of cardiovascular effects of dexamethasone and betamethasone in the first week after their administration. This trial is nested within the A*STEROID blinded multicentre randomised controlled trial of the two steroid preparations. Findings: Existing data suggest corticosteroids have little effect on the major measured fetal blood vessels when the baseline ultrasound is normal. In the compromised fetus, where the umbilical artery end-diastolic flow is abnormal prior to maternal corticosteroids, flow is temporarily restored in approximately 50% of cases. Whether such changes are beneficial is uncertain. Very little data exist that directly compare the short-term effects of betamethasone and dexamethasone. The SUPER- A*STEROID study described will help provide this information.

Placenta Share Discordance and Umbilical Artery Doppler Change After Antenatal Betamethasone Administration in Monochorionic Twins With Selective Intrauterine Growth Restriction: Is There a Link?

This study was designed to evaluate the degree of placenta share discordance in relation to the betamethasone-induced return of positive end-diastolic flow in monochorionic twin pregnancies with selective intrauterine growth restriction (sIUGR) and abnormal umbilical artery Doppler. Monochorionic twins with sIUGR was defined as one twin having an estimated fetal weight below the 10th percentile combined with an estimated fetal weight discordance >25%. The umbilical artery Doppler directly prior to (D0) and 24 hours (D1) and 48 hours (D2) after the first dose of betamethasone administration was recorded. The estimated individual placental weight in monochorionic twins was obtained by cutting the placenta along the vascular equator into two territories; the placenta share discordance was calculated as [(estimated individual placental weight of appropriated for gestational age twin- estimated individual placental weight of growth restricted twin)/estimated individual placental weight of appropriated for gestational age twin] × 100%. Six (23.1%) of the 26 included cases achieved betamethasone-induced return of positive umbilical artery end-diastolic flow. The difference of placenta share discordance and birth weight discordance were not significantly different between twins with and without betamethasone-induced return of positive umbilical artery end-diastolic flow. Thus, according to our study results, it was proposed that although the placenta share discordance correlated with the abnormal umbilical artery Doppler in the IUGR fetus in monochorionic twin, the betamethasone-induced return of positive umbilical artery end-diastolic flow, however, did not reveal the similar relationship with the severity of placenta share discordance.