Unintended pregnancy rate
This article describes a ratio measure. In the standard operationalization, the numerator of the measure is number of unintended pregnancies (view other ratio measures with this numerator) and the denominator of the measure is number of females of childbearing age (view other ratio measures with this denominator). The denominator used for reporting is 1000. The measurement period is a year.
The numerator counts the number of occurrences of an event during the measurement period.
The denominator counts the total count of some type of entity, and an appropriate convention is set regarding the time within the measurement period that this count is calculated.
The unintended pregnancy rate of a population in a given year is defined as the number of unintended pregnancies in that population per 1000 women of childbearing age in the given year. Note that this includes both the unintended pregnancies that result in births and the unintended pregnancies that do not result in births (due to abortion or unintended fetal death).
What does it take to compute the unintended pregnancy rate?
The unintended pregnancy rate is not measured based on data collection for all (or the vast majority of) pregnancies. Rather, it is estimated based on data collection for a representative sample of pregnancies. The estimation procedures have not been standardized and a lot of data on unintended pregnancy rates is in rudimentary form.
The issues with measurement are:
- There is no central registration process for pregnancies (unlike births, which tend to be registered during the process of generating birth certificates).
- There is no central record of abortions. If there were, then abortions plus births (including live births and stillbirths) would give an almost complete picture of (detected) pregnancies. A number of detected pregnancies that spontaneously abort would go unrecorded.
- There is no standardized process for determining whether a give birth was intended. This is not part of the data collection done at the time of birth.