ABORTION AND PERINATAL MORTALITY RATES

: In Great Britain the current procedures used to calculate the perinatal mortality rate are not in compliance with international recommendations for compiling perinatal statistics. In Britain, perinatal mortality rates are defined as the number of stillbirths and the number of 1st week death/1000 total births, and a still birth is defined as the birth of a child after the 28th week of gestation which does not show any signs of life. A fetal death which occurs prior to the 28th week but which is not expelled until the 28th week is counted as a stillbirth while a fetal death which occurs prior to the 28th week and is expelled immediately is not counted as a stillbirth. Furthermore the numerator excludes all babies born before the 28th week while the denominator includes those born live before the 28th week. The numerator and denominator therefore, do not relate to the same population. The distortion introduced by this inappropriate use of a proportion is increasing given improvements in prenatal care. Increasing the availability of legal abortion can also produce a decline in the perinatal mortality rate, when calculated in this fashion, without any improvement in perinatal care. In 1978, 63% of the abortions performed in Britain were performed on unmarried women and 27% were performed on women less than 19 years of age. The risk of perinatal death is known to be high among unmarried and younger aged women. Abortion, therefore, removes a number of high risk pregnancies and reduces the perinatal mortality rate. If perinatal mortality rates were computed on the basis of the number of perinatal and stillbirths/1000 viable pregnancies these distortions would be avoided.