Trends in pregnancies and pregnancy rates: estimates for the United States, 1980-92
- Hyattsville National Center for Health Statistics; CDC 2000
- 47
- (Vital and Health Statistics; 21. Data on Natality, Marriage and Divorce; 57) .
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ABORTO ABORTO ESPONTANEO EMBARAZO MORTALIDAD FETAL PARTO ESTADOS UNIDOS