Our approach to the use of antenatal steroids is to treat all mothers in preterm labor, except those with insulin dependent diabetes mellitus, ≥ 34 weeks GA, or if delivery is imminent. Steroids are then repeated weekly until delivery. The objective of this study was to compare the impact of one full course (12 mg IM × 2 doses) of betamethasone with those who received an initial course plus serial doses of 12 mg IM weekly (2-12 doses) on incidence of RDS, BPD, PDA, Grade 3 & 4 IVH, sepsis, NEC, and ROP. 163 infants were born to mothers who received one course of steroids (BW = 2255 ± 871 gms, GA = 34.2 ± 4.4 weeks). 211 infants were exposed to serial antenatal steroid treatment (BW = 2087 ± 812 gms, GA = 33.6 ± 3.8 weeks). Chi square for linear trend was used to evaluate the dose response effect for all the infants, and for infants stratified by GA of 24 to 28 weeks(n = 48, BW 856 ± 235 gm SD & 894 ± 215 gm SD), 29 to 32 weeks (n = 77, BW 1688 ± 333 gm SD & 1558 ± 392 gm), and 32 to 36 wks (n = 138, BW 2221 ± 488 gm SD & 2222 ± 514 gm) for single and serial courses of steroids.

A higher risk for NEC in the serial steroid group was identified; 0.6% vs 1.9%, p <0.04. There was a reduced risk of RDS in the 24 - 28 week group with serial dosing; 71% vs 100%, p <0.001). Infants in the 24 - 28 week group exposed to serial steroids had a trend towards less Grade 3 & 4 IVH as compared to single course steroid treatment (3.6% vs. 15%; p =ns). There was no increase in risk of endometritis or chorioamnionitis with increased number of steroid treatments. From these data, infants who were exposed to serial weekly antenatal steroids may be at an increased risk of NEC. Repeated doses of antenatal steroid as compared to single course may reduce the risk of RDS and IVH in the extremely low birth weight group.