Classifying perinatal death: experience from a regional survey

Abstract

Objective To examine problems encountered in classifying perinatal death using the systems proposed by Hey et al. (1986) and Cole et al. (1986). Subjects 451 deaths from a regional perinatal mortality survey of which 293 had a post mortem examination. Methods Documents from each death were reviewed by four assessors, one from each discipline, selected randomly from a pool of obstetricians, paediatricians, general practitioners and midwives. Each assessor classified the cause of death blind to the others. The degree of agreement between assessors was calculated for the full and shortened obstetric and fetal‐neonatal classifications using the kappa statistic for inter‐rater agreement. Results The kappa statistic, which is a measure of the proportion of agreement above chance, gave a value of 0.55 for the full obstetric classification and 0.58 for the full fetal and neonatal classification when all four assessors made an assignment. An assignment was omitted in 6.2%, but the kappa value of zero for these omissions suggested that this was a nonsystematic result due to random protocol violations. The grouped (shortened) classifications generated a higher kappa value of 0.62 for the nine point obstetric system and 0.67 for the six point fetal and neonatal (New Wigglesworth) system. Post mortem had little effect on agreement. The best agreement levels observed were for congenital anomaly. Conclusion This survey highlighted the complexity of the 22 and 24 point classifications, the uneven distribution of deaths within their categories, and the variable levels of agreement between professionals classifying deaths, thus questioning the validity of individual maternity units of health districts generating local data in this degree of detail for comparative purposes in regional and national statistics. Grouping the original categories led to greater agreement particularly for the New Wigglesworth classification. The role of post mortems in clarifying the cause of fetal and neonatal death needs further investigation.

Analysis of perinatal mortality in a Nigerian teaching hospital

“…Many of these are, however, either too long, too detailed or too technical for use in developing countries (Settatree, 1993). In low resource settings such as Nigeria, the Wigglesworth Classification (Wigglesworth, 1980) has the most appeal, as the subgroups are mutually exclusive and classification does not require sophisticated diagnostic methods.…”

The Dutch Perinatal Audit Project: a feasibility study for nationwide perinatal audit in the Netherlands

“…The audit groups classified the cause of death using three different classifications: the Modified Aberdeen Classification (18), the Extended Wigglesworth Classification (19) and the Fundamental Tulip Classification (20). The Modified Aberdeen Classification and the Extended Wigglesworth Classification are hierarchical classification models composed to reveal the obstetrical and/or neonatal causes of perinatal death and are generally used in international comparisons.…”

Classification of perinatal deaths: Development of the Australian and New Zealand classifications

“…found an 85% interobserver agreement rate for this classification and devised a decision tree to assist its application. Settatree and Watkinson 19 examined interobserver agreement for the amended Aberdeen 6,9 and the Fetal and Neonatal Factors 15 classifications and found better agreement between assessors for the classifications grouped into six or nine categories (kappas of 0.62 and 0.67) compared with the classifications expanded into 22−24 categories (kappas of 0.55 and 0.58). A high proportion of unexplained deaths (about 43%) resulted with use in the Danish Faroe Islands of these two classifications 28 .…”