Table 7.

Cigarettes Effects on OFC Incidence Based on Weighted Models

Model	Probit Regression Coefficient	APE of smoking versus no smoking on incidence	APE of current smokers quitting on incidence
Cigarettes before pregnancy
Probit	0.0068* (0.0039)	0.0004* [−0.00005, 0.00097]	−0.00017* [−0.00038, 0.00002]
Two stage IV probit – Instrument Specification 1	0.06** (0.0234)	0.0049* [−0.00004, 0.0141]	−0.0014* [−0.0029, 0.00002]
Cigarettes in the first trimester
Probit	0.0098* (0.0058)	0.0004* [−0.00004, 0.001]	−0.00012 [−0.0003, 0.00001]
Two stage IV probit – Instrument Specification 1	0.0884* (0.0459)	0.0055 [−0.002, 0.0256]	−0.001 [−0.0028, 0.0008]

Note: The table reports the regression coefficients of cigarettes in the OFC functions that are weighted by the sampling probability weights. Standard errors of regression coefficients are in parentheses. The average partial effects (APE) of smoking the “weighted” averages of cigarettes among smokers (about 9 cigarettes per day for smoking before pregnancy and 6 cigarettes per day for smoking during the first pregnancy trimester) relative to not smoking on the incidence of OFC are reported. The APE of all current smokers quitting on OFC incidence is also reported. The 95% CI of the APE based on 2000 bootstrap replications are in brackets. The models are based on a sample size of 856 observations.

^*p < 0.1,

^**p < 0.05,

^***p < 0.01.