Patterns of antenatal corticosteroid prescribing 1998-2004

The administration of antenatal corticosteroids to women at risk of preterm birth is an important component of care for such women. However, inevitably, attempts to maximise the number of women who receive corticosteroids ahead of preterm birth will also expose women perceived at risk who subsequently deliver at term. These women have not been previously quantified.

To describe antenatal corticosteroid prescribing practices at a single institution over a seven-year period.

Interrogation of an electronic birthing outcome system supplemented by hand-searching of medical records, recording all women birthing before 34 weeks and all women with a hospital admission before 34 weeks but birthing after 34 weeks. The number of women receiving antenatal corticosteroids in each of these groups was recorded, and trends between groups and over time were analysed using logistic regression.

While the total number of women receiving antenatal corticosteroids in our institution has risen over the last seven years, the proportion of women receiving antenatal corticosteroids who deliver between 24 and 35 weeks has increased inconsistently and modestly (average increase 12% per year (95% CI: 6-19%, P < 0.001). In contrast, the number of women receiving antenatal corticosteroids who subsequently deliver after 34 weeks has increased consistently, with an average increase rate of 21% per year (95% CI: 16-25%, P < 0.001).

Increasing numbers of women birthing after 34 weeks in our hospital are receiving antenatal corticosteroids before 34 weeks. The long-term implications of this are not currently clear.