Table 3.

Time trend of miscarriage rates: Proportional hazard estimates for year of pregnancy (one-step procedure) and trend on year of pregnancy dummy variables (two-step procedure)

	One-Step Procedure	Two-Step OLS	Two-Step Quantile Regression	Two-Step Robust Regression
Aged 13–25
All miscarriages	0.006* (0.003)	0.009** (0.003)	0.008† (0.004)	0.009** (0.003)
Early miscarriages	0.012† (0.006)	0.016*** (0.004)	0.015* (0.007)	0.015** (0.005)
Middle miscarriages	0.007 (0.005)	0.009* (0.004)	0.009 (0.006)	0.008† (0.004)
Late miscarriages	−0.000 (0.006)	0.001 (0.005)	−0.003 (0.006)	−0.001 (0.005)
Aged 13–35
All miscarriages	0.007* (0.003)	0.009** (0.002)	0.009* (0.003)	0.008** (0.002)
Early miscarriages	0.015** (0.005)	0.019*** (0.004)	0.017** (0.006)	0.017*** (0.003)
Middle miscarriages	0.007 (0.004)	0.007* (0.003)	0.006† (0.003)	0.007* (0.003)
Late miscarriages	−0.001 (0.005)	−0.000 (0.005)	0.002 (0.006)	−0.001 (0.005)

Notes: Standard errors clustered by respondent are reported in parentheses. Early miscarriages: within the first 7 weeks; middle miscarriages: between weeks 7 and 12; late miscarriages: after week 12 of gestation. First step of adjusted estimates controls for race, religion, maternal and own education, prior miscarriage, whether pregnancy occurred at “the right time,” and age at conception.

Source: Authors calculations from National Survey of Family Growth data.

^†p <.10;

^*p <.05;

^**p <.01;

^***p <.001