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.