Measurements
The main outcome variable in this study is adverse pregnancy outcomes for the most recent pregnancy. A binary variable was coded for adverse pregnancy/ birth outcomes in which all pregnancies that were either miscarriage or stillbirths were coded 1, while pregnancies that resulted in a live birth were coded 0. To estimate the effect of GEHIP’s community-based primary healthcare program on adverse birth outcomes, the Heckman difference-in-differences (DID) regression analysis is applied to estimate its average treatment effects . Equation 1 is a reduced form of the DID.