Table 5

ATTs of HSP participation on birth weight and PTB

HSP population	ELBW					PTB
HSP population	HSP %	Matched %	ATT	95% CI*	P value*	HSP %	Matched %	ATT	95% CI*	P value*
Statewide	0.22	0.45	−0.23	−0.39 to –0.06	0.007	7.38	7.48	−0.28	−0.87 to 0.66	0.793
Rural border counties	0.21	0.50	−0.29	−0.60 to 0.02	0.068	5.81	6.82	−1.01	−2.31 to 0.28	0.126
Latina	0.19	0.50	−0.31	−0.52 to –0.10	0.005	7.16	7.66	−0.50	−1.48 to 0.48	0.314
American Indian	0.23	0.26	−0.03	−0.42 to 0.37	0.894	8.10	7.89	0.20	−1.99 to 2.40	0.855
Teen mothers (age: <20 years)	0.47	0.30	0.18	−0.27 to 0.62	0.440	6.65	9.45	−2.81	−4.71 to –0.91	0.004
Pre-existing health risk†	0.12	0.30	−0.17	−0.52 to 0.17	0.222	16.03	15.69	0.34	−2.96 to 3.65	0.314

*ATT and p value based on estimated propensity score.
†Pre-existing health risks defined as the presence of pre-existing (non-gestational) diabetes and hypertension.
ATTs, average treatment-on-the-treated effects; ELBW, extremely low birth weight; HSP, Health Start Programme; PTB, preterm birth.