Table 18 presents late foetal deaths by age of mother and total-birth order for as many years as possible between 1990 and 1998.
Descriptions of variables: Late foetal deaths are foetal deaths of 28 or more complete weeks of gestation. Foetal deaths of unknown gestational age are included with those of 28 or more weeks.
Age of mother is defined as age at last birthday, that is the difference between the date of birth and the date of the occurrence of the event, expressed in completed solar years. The age classification used in this table is the following less than 15 years, 5-year age groups through 40-44 years, 45 years and over and age unknown.
Total birth order is defined as the numerical order of the late foetal deaths being recorded, in relation to all previous issue of the mother, irrespective of whether the issue was live-born or born dead (foetal death), or whether pregnancies were nuptial or extra-nuptial. Except where otherwise indicated 11 categories are used to classify total-birth order: 1 through 9, 10 or more total births and unknown.
Reliability of data: Data from civil registers of late foetal deaths which are reported as incomplete (less than 90 per cent completeness are considered unreliable and are set in italics rather than in roman type. Table 15 and the technical notes for that table provide more detailed information on the completeness of late foetal death registration. For more information about the quality of vital statistics in general, and the information available on the basis of the completeness estimates in particular, see section 4.2 of the Technical Notes.
Limitations: Statistics on late foetal deaths by age of mother and total birth-order are subject to the same qualifications as have been set forth for vital statistics in general and foetal-death statistics in particular as discussed in section 4 of the Technical Notes.
The reliability of data, an indication of which is described in the above paragraph, is a very important factor. Of all vital statistics, the registration of foetal deaths is probably the most incomplete.
Variation in the definition of foetal deaths, and in particular late foetal deaths, also limits international comparability. The criterion of 28 or more completed weeks of gestation to distinguish late foetal deaths is not universally used; some countries or areas use different lengths of gestation or other criteria such as length of the foetus. In addition, the difficulty of accurately determining gestational age further reduces comparability.
Another factor introducing variation in the definition of late foetal deaths is the practice by some countries or areas to consider infants who died before the registration of birth or within the first 24 hours of live as foetal deaths instead of live births, thus overestimating the total number of late foetal deaths. Statistics of this type are footnoted.
As in other age distributions, lack of frequencies in the unknown-age-of-mother category is not necessarily an indication of accurate age reporting. In some cases, late foetal deaths for which age of mother was unknown were distributed among known age frequencies before tabulation; in others, marked decreases in the frequencies in the unknown order of late foetal deaths are usually correlated with small frequencies of first birth order. This may be due to failure to record a reply to the question when the response is “none”. This same problem appears in data on women by number of children ever born.
Reporting errors are another possibility to be borne in mind in using these data. For example very large numbers of births reported at high birth orders and young ages of mother are not credible; these are probably due to age-reporting errors.
Coverage: Late foetal deaths by age of mother and total birth-order are shown for 50 countries or areas.
Earlier data: Late foetal deaths by age of mother and total-birth order have been shown previously in issues of the Demographic yearbook featuring natality. For information on years covered, readers should consult the Index.