The rates of preterm birth in the study population were 66.9% (327/489)
at o37 weeks and 19.4% (95/489) at o32 weeks. Prior to
37 weeks, 50.2% (164/327) of the births were spontaneous and
49.8% (163/327) were medically indicated. Bivariate analysis
comparing patients delivering before and after 32 weeks demonstrated
no difference in demographic variables or the proportion
of patients with inadequate gestational weight gain at o20 weeks (Table 2). The rate
of prior spontaneouspreterm birth was higher in the group delivering at
o32 weeks (9.5% vs 5.8%); however, this was not statistically
significant. Monochorionic twin pregnancy, short cervical length
and inadequate gestational weight gain at 20 to 28 weeks were more common in
the group delivering at o32 weeks (Table 2).