Abortions per 1,000 live births
This is the abortion rate, representing the number of induced abortions occurring in a specified reference period (e.g., one year) per 1,000 women of reproductive age (15-44 or 15-49).
The abortion rate (AR) is calculated as:
|# of abortions x 1000
Total mid-year population of women 15-44 (or 49)
The total abortion (TAR) rate is the total number of abortions a woman will have in her lifetime if current levels persist. This lifetime risk is a cohort measure and can be calculated with period measures (age-specific abortion rates) or approximated by multiplying the abortion rate by the length of the reproductive period (30-35 years), (Bertrand and Tsui, 1995). Thus, the total abortion rate is calculated as:
|TAR= 35 x abortion rate|
Where: 35 = # of years of reproductive life span.
Total number of induced abortions occurring in a given year or reference period; the enumerated or estimated mid-period population for the same period
Data on abortions: where abortion laws are liberal, official statistics are likely to provide the most accurate numbers; where abortion is restricted, data will be less accurate but one may derive estimates from surveys of providers, population-based surveys, hospital-based studies, or a combination of sources.
Census data or projections based on census data usually provide information on the population of women 15-49.
Rates and ratios are two of the most widely used abortion measures. They are indispensable statistics for documenting levels of abortion across time and space. The abortion rate is a useful tool in the evaluation of contraceptive services, either for the purpose of setting a baseline or for measuring progress. The abortion rate reflects contraceptive method and user effectiveness, as well as access to services. The rate is less useful than facility-based or other data for the evaluation of demonstration projects or the effects of separate program components.
Several factors affect the rate: 1) the proportion of women who become pregnant in a year; 2) the likelihood a pregnancy is unwanted; and 3) the likelihood an unwanted pregnancy will be terminated. Consequently, increasing effective contraceptive use and thus decreasing the number of unwanted pregnancies can lower the abortion rate, while potentially lowering fertility. On the other hand, if the number of pregnancies is constant but more unwanted pregnancies are carried to term, the abortion rate will also decrease, with the effect of potentially increasing fertility.
Like the total fertility rate, the TAR is easily understood and serves as an effective statistic for comparative purposes. The advantage of the TAR is that is takes into account the probability of becoming pregnant and the probability of terminating each pregnancy throughout the reproductive life cycle. Like the abortion rate, a high TAR may indicate several factors, including the availability and quality (or lack thereof) of contraceptive services. A high TAR may also reflect a high prevalence of traditional contraceptive method use in a given country.
Development of the abortion rate by specific age ranges (such as 15-19 or 24) can also be a useful tool for documentation of those groups at particular risk for abortion.
Rates and ratios are often seriously compromised in terms of accuracy. As stated above, where abortion is restricted, data are likely to be inaccurate. In these circumstances, data may require adjusting for underreporting, misclassification or socioeconomic conditions that reflect the safety of clandestine abortion and the likelihood that a woman with complications from an induced abortion seeks and receives treatment. Even in less restricted settings, research has shown that women underreport their abortion experiences. Where judicial reprisal or severe physical or psychological damage is a possibility, accurate reporting is even less likely. For years, researchers have attempted different methods for collecting sensitive and personal information at little or no threat to the research subjects. The National Survey of Family Growth in the United States includes computer-assisted interviews, which maximize a respondent‘s privacy.
postabortion care, family planning