Table 2.

Relative risks (and 95% confidence intervals) for childhood obesity^a by prenatal exposure to second or third trimester antibiotics and mode of delivery: the Mothers and Newborns Study in Northern Manhattan and South Bronx

	Cases/ n	Model 1	Model 2	Model 2+exclusion of children whose mothers had gestational diabetes or preeclampsia
2nd or 3rd trimester antibiotics
No	85/366	1 (Reference)	1 (Reference)	1 (Reference)
Yes	25/70	1.83 (1.36, 2.47)	1.84 (1.33, 2.54)	1.77 (1.25, 2.51)
Mode of delivery
Vaginal	77/337	1 (Reference)	1 (Reference)	1 (Reference)
Cesarean	33/99	1.43 (1.06, 1.92)	1.46 (1.08, 1.98)	1.41 (1.01, 1.96)

All models exclude those missing information on pre-gravid BMI, gestational age and birth weight, and only include those with gestational age <37 weeks. Model 1: adjusted for sex, ethnicity (Dominican/African-American), offspring birth weight (tertiles), maternal age (tertiles), maternal pre-gravid BMI (tertiles), receipt of public assistance during pregnancy (yes/no) and prenatal antibiotic use or delivery mode. Model 2: additionally adjusted for having breastfed in first year (yes/no). Log-binomial models were used to generate relative risk and 95% confidence interval. N =411 after exclusion of mothers diagnosed with gestational diabetes and preeclampsia during pregnancy

^aObesity defined as BMI percentile ≥95th percentile.