Appropriate antenatal corticosteroid use in women at risk for preterm birth before 34 weeks of gestation

Abstract

Objective: To determine the utilisation of antenatal corticosteroid administration in women presenting at risk of preterm birth (PTB) in a centre where tocolytics are not prescribed.

Design: A prospective cohort study.

Setting: Tertiary referral centre, Dublin, Ireland.

Population: Four hundred and fourteen consecutive women presenting at risk of PTB.

Methods: Clinical details were collated prospectively on all booked patients who presented at risk of PTB (i.e. at <34 weeks of gestation) during 2008.

Main outcome measure: Rate of administration of antenatal corticosteroids in PTB.

Results: Of 8985 deliveries, 414 women (5%) presented at <34 weeks of gestation with a clinical potential for PTB, of whom 277 (67%) received antenatal corticosteroids. Amongst women delivering at <34 weeks of gestation, 93% (80/86) received any corticosteroids and 76% (65/86) received a complete course. The ratio of women given a complete course of corticosteroids to the number who actually delivered before 34 weeks of gestation was 4:1 overall. Analysis by indication for PTB revealed this ratio to be 15:1 in suspected preterm labour (PTL), 8:1 in antepartum haemorrhage (APH), and 2:1 in both preterm prelabour rupture of membranes (PPROM) and medically indicated PTB (MIPTB). Seven of ten multiparae (70%) who delivered prematurely during the study period following PTL had a history of previous PTL before 34 weeks of gestation.

Conclusion: The ratio of maternal antenatal corticosteroid administration for potential versus actual PTB at <34 weeks of gestation was high in categories such as PTL and substantial APH, whereas selection in PPROM and MIPTB approached 100%. There should be a low threshold for single course therapy for women with prior PTL before 34 weeks of gestation.