1. Hay et al. 780 pregnant women screened at fist prenatal care visit primarily examining PTD; 467 women screened before 16 weeks capture sab’s 12% prevalence of BV - only included 9 cases of SAB.

2. McGregor et al over 100 women screened at first prenatal care visit for BV to examine sab, ptd and pprom. Found a three-fold increased risk but included only 27 cases of sab.

3. Ralph et al. enrolled 867 women with a history of three or more sabs and more than a two fold increase in sab among women with BV after adjusting for age, prior live birth and reported smoking. Conception rates did not differ between the two groups.