Abortion
The index of abortion is intended to measure the inhibiting effects of induced abortion. The equation for the index is calculated by recognising that each abortion will avert somewhat less than one birth because: (a) a spontaneous abortion or still birth may have prevented the pregnancy from ending in a live birth, and (b) following an induced abortion a woman resumes ovulation much sooner than would have been the case had she carried the pregnancy to term, meaning that subsequent pregnancy is likely to follow sooner.
Ca = TFR / {TFR + 0.4 × (1 + u) × TA}
where
- TA = Total abortion rate. Total number of abortions over the reproductive period per woman among only married women.
- u = contraceptive prevalence