Fundamental classification of perinatal death. Validation of a new classification system of perinatal death

Stillbirth diagnosis and classification: comparison of ReCoDe and ICD-PM systems

OBJECTIVES

The identification of causes of stillbirth (SB) can be a challenge due to several different classification systems of SB causes. In the scientific literature there is a continuous emergence of SB classification systems, not allowing uniform data collection and comparisons between populations from different geographical areas. For these reasons, this study compared two of the most used SB classifications, aiming to identify which of them should be preferable.

METHODS

A total of 191 SBs were retrospectively classified by a panel composed by three experienced-physicians throughout the ReCoDe and ICD-PM systems to evaluate which classification minimizes unclassified/unspecified cases. In addition, intra and inter-rater agreements were calculated.

RESULTS

ReCoDe defined: the 23.6% of cases as unexplained, placental insufficiency in the 14.1%, lethal congenital anomalies in the 12%, infection in the 9.4%, abruptio in the 7.3%, and chorioamnionitis in the 7.3%. ICD-PM defined: the 20.9% of cases as unspecified, antepartum hypoxia in the 44%, congenital malformations, deformations, and chromosomal abnormalities in the 11.5%, and infection in the 11.5%. For ReCoDe, inter-rater was agreement of 0.58; intra-rater agreements were 0.78 and 0.79. For ICD-PM, inter-rater agreement was 0.54; intra-rater agreements were of 0.76 and 0.71.

CONCLUSIONS

There is no significant difference between ReCoDe and ICD-PM classifications in minimizing unexplained/unspecified cases. Inter and intra-rater agreements were largely suboptimal for both ReCoDe and ICD-PM due to their lack of specific guidelines which can facilitate the interpretation. Thus, the authors suggest correctives strategies: the implementation of specific guidelines and illustrative case reports to easily solve interpretation issues.

Fetal death: an extreme manifestation of maternal anti-fetal rejection

OBJECTIVE

The aim of this study was to determine the association between chronic placental inflammation and amniotic fluid (AF) markers of maternal anti-fetal rejection as well as the presence of microorganisms in the AF fluid of patients with fetal death.

STUDY DESIGN

This cohort study included 40 patients with fetal death whose placentas were examined for chronic inflammatory lesions and whose AF chemokine ligand (CXCL)10 and interleukin (IL)-6 concentrations were determined by immunoassays. AF was processed for bacteria, mycoplasmas and viruses using cultivation and molecular microbiologic techniques (i.e. PCR-ESI/MS).

RESULTS

(1) The most prevalent placental findings were maternal vascular underperfusion (63.2%, 24/38), followed by chronic inflammatory lesions (57.9%, 22/38); (2) chronic chorioamnionitis (18/38) was three times more frequent than villitis of unknown etiology (6/38); (3) an elevated AF CXCL10 concentration (above the 95th centile) was present in 60% of the cases, and a receiver operating characteristics (ROC)-derived cut-off of 2.9 ng/mL had a sensitivity of 73% and a specificity of 75% in the identification of chronic placental inflammatory lesions; (4) only five cases had microbial invasion of the amniotic cavity, and the presence of microorganisms did not correlate with chronic placental inflammation.

CONCLUSION

In women with unexplained fetal death, there is an association between elevated AF CXCL10 and chronic placental inflammatory lesions. Therefore, we conclude that a subset of patients with fetal death may have endured a breakdown of maternal-fetal tolerance, which cannot be attributed to microorganisms in the amniotic cavity.

The Stillbirth Classification System for the Safe Passage Study

Objective Describe the classification system for assigning the cause of stillbirth in the Safe Passage Study, an international, multi-institutional, prospective analysis conducted by the NIAAA/NICHD-funded Prenatal Alcohol in SIDS and Stillbirth (PASS) Research Network. The study mission is to determine the role of prenatal alcohol and/or cigarette smoke exposure in adverse pregnancy outcomes, including stillbirth, in a high-risk cohort of 12,000 maternal/fetal dyads. Methods The PASS Network classification system is based upon 5 "sites of origin" for cause of stillbirth, further subdivided into mechanism subcategories; both are employed to assign an ultimate cause of death. Each PASS stillbirth was assigned a cause of death and status of sporadic versus recurrent. Adjudication involved review of maternal and obstetrical records; fetal autopsy and placental findings; and required complete consensus in each case. Two published classification systems, ie, INCODE and ReCoDe, were used for comparison. Results Causes of stillbirth classified were fetal (26%), placental (53%), external (5%), and undetermined (16%). Nine cases (47%) had placental causes of death due to maternal disorders that carry recurrence risks. There was full agreement for cause of death across the 3 classification systems in 26% of cases and partial agreement among them in 42% of cases. Conclusions The proposed PASS schema employs a user-friendly classification that provides comparable information to previously published systems. Advantages include its simplicity, mechanistic formulations, tight clinicopathologic integration, provision for an undetermined category, and its wide applicability to perinatal mortality review boards with access to information routinely collected during clinicopathologic evaluations.

Seeking order amidst chaos: a systematic review of classification systems for causes of stillbirth and neonatal death, 2009-2014

BACKGROUND

Each year, about 5.3 million babies die in the perinatal period. Understanding of causes of death is critical for prevention, yet there is no globally acceptable classification system. Instead, many disparate systems have been developed and used. We aimed to identify all systems used or created between 2009 and 2014, with their key features, including extent of alignment with the International Classification of Diseases (ICD) and variation in features by region, to inform the World Health Organization's development of a new global approach to classifying perinatal deaths.

METHODS

A systematic literature review (CINAHL, EMBASE, Medline, Global Health, and PubMed) identified published and unpublished studies and national reports describing new classification systems or modifications of existing systems for causes of perinatal death, or that used or tested such systems, between 2009 and 2014. Studies reporting ICD use only were excluded. Data were independently double-extracted (except from non-English publications). Subgroup analyses explored variation by extent and region.

RESULTS

Eighty-one systems were identified as new, modifications of existing systems, or having been used between 2009 and 2014, with an average of ten systems created/modified each year. Systems had widely varying characteristics: (i) comprehensiveness (40 systems classified both stillbirths and neonatal deaths); (ii) extent of use (systems were created in 28 countries and used in 40; 17 were created for national use; 27 were widely used); (iii) accessibility (three systems available in e-format); (iv) underlying cause of death (64 systems required a single cause of death); (v) reliability (10 systems tested for reliability, with overall Kappa scores ranging from .35-.93); and (vi) ICD alignment (17 systems used ICD codes). Regional databases were not searched, so system numbers may be underestimated. Some non-differential misclassification of systems was possible.

CONCLUSIONS

The plethora of systems in use, and continuing system development, hamper international efforts to improve understanding of causes of death. Recognition of the features of currently used systems, combined with a better understanding of the drivers of continued system creation, may help the development of a truly effective global system.

Classification of stillbirths is an ongoing dilemma

AIM

To compare different classification systems in a cohort of stillbirths undergoing a comprehensive workup; to establish whether a particular classification system is most suitable and useful in determining cause of death, purporting the lowest percentage of unexplained death.

METHODS

Cases of stillbirth at gestational age 22-41 weeks occurring at the Department of Gynecology and Obstetrics of Foggia University during a 4 year period were collected. The World Health Organization (WHO) diagnosis of stillbirth was used. All the data collection was based on the recommendations of an Italian diagnostic workup for stillbirth. Two expert obstetricians reviewed all cases and classified causes according to five classification systems.

RESULTS

Relevant Condition at Death (ReCoDe) and Causes Of Death and Associated Conditions (CODAC) classification systems performed best in retaining information. The ReCoDe system provided the lowest rate of unexplained stillbirth (14%) compared to de Galan-Roosen (16%), CODAC (16%), Tulip (18%), Wigglesworth (62%).

CONCLUSION

Classification of stillbirth is influenced by the multiplicity of possible causes and factors related to fetal death. Fetal autopsy, placental histology and cytogenetic analysis are strongly recommended to have a complete diagnostic evaluation. Commonly employed classification systems performed differently in our experience, the most satisfactory being the ReCoDe. Given the rate of "unexplained" cases, none can be considered optimal and further efforts are necessary to work out a clinically useful system.

Classification systems for causes of stillbirth and neonatal death, 2009-2014: an assessment of alignment with characteristics for an effective global system

Background

To reduce the burden of 5.3 million stillbirths and neonatal deaths annually, an understanding of causes of deaths is critical. A systematic review identified 81 systems for classification of causes of stillbirth (SB) and neonatal death (NND) between 2009 and 2014. The large number of systems hampers efforts to understand and prevent these deaths. This study aimed to assess the alignment of current classification systems with expert-identified characteristics for a globally effective classification system.

Methods

Eighty-one classification systems were assessed for alignment with 17 characteristics previously identified through expert consensus as necessary for an effective global system. Data were extracted independently by two authors. Systems were assessed against each characteristic and weighted and unweighted scores assigned to each. Subgroup analyses were undertaken by system use, setting, type of death included and type of characteristic.

Results

None of the 81 systems were aligned with more than 9 of the 17 characteristics; most (82 %) were aligned with four or fewer. On average, systems were aligned with 19 % of characteristics. The most aligned system (Frøen 2009-Codac) still had an unweighted score of only 9/17. Alignment with individual characteristics ranged from 0 to 49 %. Alignment was somewhat higher for widely used as compared to less used systems (22 % v 17 %), systems used only in high income countries as compared to only in low and middle income countries (20 % vs 16 %), and systems including both SB and NND (23 %) as compared to NND-only (15 %) and SB-only systems (13 %). Alignment was higher with characteristics assessing structure (23 %) than function (15 %).

Conclusions

There is an unmet need for a system exhibiting all the characteristics of a globally effective system as defined by experts in the use of systems, as none of the 81 contemporary classification systems assessed was highly aligned with these characteristics. A particular concern in terms of global effectiveness is the lack of alignment with “ease of use” among all systems, including even the most-aligned. A system which meets the needs of users would have the potential to become the first truly globally effective classification system.

Electronic supplementary material

The online version of this article (doi:10.1186/s12884-016-1040-7) contains supplementary material, which is available to authorized users.

Characteristics of a global classification system for perinatal deaths: a Delphi consensus study

BACKGROUND

Despite the global burden of perinatal deaths, there is currently no single, globally-acceptable classification system for perinatal deaths. Instead, multiple, disparate systems are in use world-wide. This inconsistency hinders accurate estimates of causes of death and impedes effective prevention strategies. The World Health Organisation (WHO) is developing a globally-acceptable classification approach for perinatal deaths. To inform this work, we sought to establish a consensus on the important characteristics of such a system.

METHODS

A group of international experts in the classification of perinatal deaths were identified and invited to join an expert panel to develop a list of important characteristics of a quality global classification system for perinatal death. A Delphi consensus methodology was used to reach agreement. Three rounds of consultation were undertaken using a purpose built on-line survey. Round one sought suggested characteristics for subsequent scoring and selection in rounds two and three.

RESULTS

The panel of experts agreed on a total of 17 important characteristics for a globally-acceptable perinatal death classification system. Of these, 10 relate to the structural design of the system and 7 relate to the functional aspects and use of the system.

CONCLUSION

This study serves as formative work towards the development of a globally-acceptable approach for the classification of the causes of perinatal deaths. The list of functional and structural characteristics identified should be taken into consideration when designing and developing such a system.

Classification of substandard factors in perinatal care: development and multidisciplinary inter-rater agreement of the Groningen-system

Background

Perinatal audit is an established method for improving the quality of perinatal care. In audit meetings substandard factors (SSF) are identified in cases of perinatal mortality and morbidity. To our knowledge there is no classification system specifically designed for the classification of substandard factors. Such a classification may help to standardise allocation of substandard factors to categories. This will help to prioritise, guide and implement actions in quality improvement programs.

Methods

A classification system of 284 substandard factors (SSF) identified in perinatal audit meetings between 2007 and 2011 was drawn up using the WHO Conceptual Framework for the International Classification for Patient Safety as a starting point. Discussions were held on inter-rater disagreements, inclusion of items, format and organisation and definitions of the main- and subcategories. A guideline was developed. An independent multidisciplinary group tested the classification. Independent of inter-rater agreement the allocations to categories were counted. For the counts in the subcategories one and two, we used the allocations in the main category as reference. The chance corrected agreement between classifiers was tested with Cohen's kappa statistic.

Results

The classification consists of 9 main categories with one or two subcategories. The main categories are (1) Equipment and Materials, (2) Medication, (3) Additional tests/ investigations, (4) Transportation , (5) Documentation, (6) Communication, (7) Medical practice, (8) Other and (9) non classifiable. Of 3663 allocations by 13 classifiers 1452 SSF’s were allocated (40 %) to ‘medical practice’ and 1247 (34 %) to ‘documentation’. 118 (3 %) times SSF’s were not classifiable, mainly due to unclear phrasing of the SSF. The chance corrected agreement of 284 substandard factors in the main category was 0.68 (95 % CI 0.66-0.70) and 0.57 (95 % CI 0.54-0.59) for the CDG and the IGD respectively.

Conclusions

Classifying substandard factors has given insight into problem area's in perinatal care and can give direction to medical, political and financial quality improvement measures.

The Groningen-system has well defined categories and subcategories and the guidelines and examples are clear. The multidisciplinary inter-rater agreement is moderate to good. Improvement of the phrasing of the substandard factors is expected to improve inter-rater agreement.

Electronic supplementary material

The online version of this article (doi:10.1186/s12884-015-0638-5) contains supplementary material, which is available to authorized users.

Cause-specific mortality of very preterm infants and antenatal events

OBJECTIVE

To assess the relationship between antenatal factors and cause-specific risk of death in a large area-based cohort of very preterm infants.

STUDY DESIGN

The ACTION (Accesso alle Cure e Terapie Intensive Ostetriche e Neonatali) study recruited during an 18-month period all infants 22-31 weeks' gestational age admitted to neonatal care in 6 Italian regions (n=3040). We analyzed the data of 2974 babies without lethal or acutely life-threatening malformations. Cause-specific risks of death adjusted for competing causes were calculated, and region-stratified multiple Cox regression analyses were used to study the association between cause-specific mortality and infants' characteristics, pregnancy complications, antenatal steroids, and place of birth.

RESULTS

Deaths attributable to respiratory problems and intraventricular hemorrhage prevailed in the first 2 weeks of life, and those attributable to infections and gastrointestinal diseases afterwards. Antepartum hemorrhage was associated with respiratory deaths (hazard ratio [HR] 1.6, 95% CI 1.1-2.4), and maternal infection with deaths attributable to asphyxia (HR 32.5, 95% CI 4.1-259.4) and to respiratory problems (HR 2.8, 95% CI 1.6-5.2). Preterm premature rupture of membranes increased the likelihood of deaths due to neonatal infection (HR 1.8, 95% CI 1.0-3.1), and preterm labor/contractions of those due to respiratory (HR 1.5, 95% CI 1.1-2.0) and gastrointestinal diseases (HR 5.8, 95% CI 2.1-16.3). In addition, a birth weight z-score<-1 was associated with increasing hazards of death resulting from asphyxia, late infections, respiratory, and gastrointestinal diseases.

CONCLUSIONS

Different complications of pregnancy lead to different cause-specific mortality patterns in very preterm infants.

Stillbirth and fetal growth restriction

OBJECTIVE

To confirm the role of fetal growth restriction (FGR) as a cause of stillbirth, and to compare diagnostic accuracy of customized fetal growth and population-based standards in identifying FGR within a pathological population of early and late stillbirths.

METHODS

Retrospective study on a cohort of 189 stillbirths occurred in single pregnancy between January 2006 and September 2011. Unexplained stillbirths, defined by Aberdeen-Wigglesworth and ReCoDe classifications, were evaluated on the basis of fetal birthweight with both Tuscany population and Gardosi customized standards. Unexplained stillbirths have been classified as early or late depending on the gestational age of occurrence.

RESULTS

Aberdeen-Wigglesworth classification, applied to the 189 cases of stillbirth, left 94 unexplained cases (49.7%), whereas the ReCoDe classification left only 40 (21%). By applying population standards to the 94 unexplained stillbirths we have identified 31 FGRs (33% of sample), while customized standards identified 54 FGRs (57%). Customised standards identified a larger number of FGRs with respect to population standards during the third trimester (i.e. 51% vs. 25% respectively) than in the second trimester (73% vs. 54% respectively) (p = 0.05).

CONCLUSIONS

Customized standards have a higher diagnostic accuracy in identifying FGRs especially during the third trimester.

The changing pattern of perinatal mortality and causes of death in central Anatolian region of Turkey

In this study, the perinatal mortality is presented in 2009 compared to 1998. Changing patterns of the perinatal mortality rate (PNMR), the stillbirth rate (SBR), early neonatal mortality rate (ENMR) and the causes of the perinatal mortality in Zekai Tahir Burak Women's Health Education and Research Hospital (ZTBH) were described. This is the largest maternity hospital of Ankara in the central Anatolian region of Turkey. The total deliveries were 22,777 and 18,567 in 1998 and 2009, respectively. PNMR was 27.7 per 1000, and SBR was 23.7 per 1000 total births. ENMR was 4 per 1000 in 1998. PNMR is 20.7 per 1000, and SBR was 16.3 per 1000 and ENMR was 4.6 per 1000 total births in 2009. It is important to know the causes of mortality. In this study, the causes of perinatal deaths were classified according to the Wigglesworth classification. Antepartum stillbirth (62.3%) was the most frequent cause in 1998. Perinatal asphyxia is the majority (46.6%) of the perinatal deaths in 2009. This study shows that even prenatal care is getting better, obstetric care as well as close follow-up throughout the intrapartum period and diminishing the preterm delivery rate is also important for preventing and reducing perinatal mortality.

Wisconsin stillbirth services program: a multifocal approach to stillbirth analysis

Stillbirth accounts for about 26,000 deaths annually in the US. In most previous studies, discrete causes are identified in less than half of all stillbirths. In order to identify causes and non-causal but potentially contributing abnormalities, we analyzed 416 of the most recent (2004-2010) Wisconsin Stillbirth Service Program (WiSSP) cases from a multifocal approach. In 70% of cases a cause sufficient to independently explain the demise was identified including 40% placental, 21.5% fetal, and 12.7% maternal. Results for stillbirths and second trimester miscarriages did not differ significantly. In 95% of cases at least one cause or non-causal abnormality was recognizable, and in two-thirds of cases, more than one cause or non-causal abnormality was identified. In cases with maternal cause, the placenta was virtually always abnormal. Both placentas (59%) and fetuses (38%) were frequently smaller than expected for gestational age. Previous miscarriage and/or stillbirth were risk factors for second and third trimester losses, with 35% of previous pregnancies ending in fetal demise. Recommendations include complete evaluation of all second and third trimester losses with special attention to placental pathology and thorough investigation for multiple causes or abnormalities whether or not a primary cause is initially recognized. Improved understanding of the causes of late miscarriage and stillbirth may contribute to recognition and management of pregnancies at risk and eventually to prevention of stillbirth.

A comparison of the Perinatal Society of Australia and New Zealand-Perinatal Death Classification system and relevant condition at death stillbirth classification systems

BACKGROUND

Stillbirths comprise two-thirds of all perinatal mortality. A classification system with low 'unexplained' stillbirth rates is important when developing prevention strategies.

AIMS

This study aims to (i) determine whether the proportion of stillbirths classified as 'unexplained' is reduced, by using the relevant condition at death (ReCoDe) stillbirth classification system, compared with the Perinatal Society of Australia and New Zealand - Perinatal Death Classification (PSANZ-PDC) system; and (ii) compare the proportion of stillbirths attributed to fetal growth restriction and other causes by each system.

METHODS

The ReCoDe stillbirth classification system was applied to the National Women's Health's stillbirth database for years 2004-2007. The proportion of stillbirths classified as 'unexplained' and as a result of fetal growth restriction was compared between the ReCoDe and the PSANZ-PDC systems using the chi(2) test.

RESULTS

The proportion of stillbirths classified as unexplained was less with ReCoDe compared with PSANZ-PDC (8.5% (n = 26) vs 14.1% (n = 43) P = 0.04). The proportion with the primary cause attributed to fetal growth restriction was increased with ReCoDe compared with PSANZ-PDC (23.2% (n = 71) vs 8.2% (n = 25) P < 0.0001). However, 44.8% (n = 137) of all stillbirths were small for gestational age (birthweight < 10th customised centile). The most common primary cause or condition at death by both systems was congenital abnormalities.

CONCLUSION

The proportion of stillbirths classified as unexplained was less with ReCoDe compared with PSANZ-PDC but rates with either method were low compared with earlier classification systems. Fetal growth restriction was listed as the primary condition more commonly with ReCoDe compared with PSANZ-PDC because of different definitions.

An evaluation of classification systems for stillbirth

Background

Audit and classification of stillbirths is an essential part of clinical practice and a crucial step towards stillbirth prevention. Due to the limitations of the ICD system and lack of an international approach to an acceptable solution, numerous disparate classification systems have emerged. We assessed the performance of six contemporary systems to inform the development of an internationally accepted approach.

Methods

We evaluated the following systems: Amended Aberdeen, Extended Wigglesworth; PSANZ-PDC, ReCoDe, Tulip and CODAC. Nine teams from 7 countries applied the classification systems to cohorts of stillbirths from their regions using 857 stillbirth cases. The main outcome measures were: the ability to retain the important information about the death using the InfoKeep rating; the ease of use according to the Ease rating (both measures used a five-point scale with a score <2 considered unsatisfactory); inter-observer agreement and the proportion of unexplained stillbirths. A randomly selected subset of 100 stillbirths was used to assess inter-observer agreement.

Results

InfoKeep scores were significantly different across the classifications (p ≤ 0.01) due to low scores for Wigglesworth and Aberdeen. CODAC received the highest mean (SD) score of 3.40 (0.73) followed by PSANZ-PDC, ReCoDe and Tulip [2.77 (1.00), 2.36 (1.21), 1.92 (1.24) respectively]. Wigglesworth and Aberdeen resulted in a high proportion of unexplained stillbirths and CODAC and Tulip the lowest. While Ease scores were different (p ≤ 0.01), all systems received satisfactory scores; CODAC received the highest score. Aberdeen and Wigglesworth showed poor agreement with kappas of 0.35 and 0.25 respectively. Tulip performed best with a kappa of 0.74. The remainder had good to fair agreement.

Conclusion

The Extended Wigglesworth and Amended Aberdeen systems cannot be recommended for classification of stillbirths. Overall, CODAC performed best with PSANZ-PDC and ReCoDe performing well. Tulip was shown to have the best agreement and a low proportion of unexplained stillbirths. The virtues of these systems need to be considered in the development of an international solution to classification of stillbirths. Further studies are required on the performance of classification systems in the context of developing countries. Suboptimal agreement highlights the importance of instituting measures to ensure consistency for any classification system.

Identifying the causes of stillbirth: a comparison of four classification systems

OBJECTIVE

To identify the classification protocol for stillbirth that minimizes the rate of unexplained causes.

STUDY DESIGN

All stillbirths at > 22 weeks from 1995-2007 underwent a workup inclusive of fetal ultrasonography, amniocentesis for karyotype and cultures, placental histology, fetal autopsy, skin biopsy, total body X-ray, maternal testing for thrombophilias, TORCH, Parvovirus spp, thyroid function, indirect Coombs, Kleiheuer-Betke test, and genital cultures. To such a cohort, we applied the 4 most commonly used classification protocols.

RESULTS

The stillbirth rate during the study period was 0.4% (154/37,958). The RoDeCo classification provided the lowest rate of unexplained stillbirth (14.3%) compared with Wigglesworth (47.4%), de Galan-Roosen (18.2%), and Tulip (16.2%) classifications. Mean gestational age at stillbirth in unexplained vs explained stillbirth was similar in the 4 protocols.

CONCLUSION

Adoption of a consistent and appropriate workup protocol can reduce the rate of unexplained stillbirth to 14%.

A placental cause of intra-uterine fetal death depends on the perinatal mortality classification system used

Different classification systems for the cause of intra-uterine fetal death (IUFD) are used internationally. About two thirds of these deaths are reported as unexplained and placental causes are often not addressed. Differences between systems could have consequences for the validity of vital statistics, for targeting preventive strategies and for counselling parents on recurrence risks. Our objective was to compare use of the Tulip classification with other currently used classification systems for causes of IUFD. We selected the extended Wigglesworth classification, modified Aberdeen and the classifications by Hey, Hovatta, de Galan-Roosen and Morrison. We also selected the ReCoDe system for relevant conditions, comparable to contributing factors in the Tulip classification. Panel classification for 485 IUFD cases in the different systems was performed by assessors after individual investigation of structured patient information. Distribution of cases into cause of death groups for the different systems varied, most of all for the placental and unknown groups. Systems with a high percentage of cases with an unknown cause of death and death groups consisting of clinical manifestations only are not discriminatory. Our largest cause of death group was placental pathology and classification systems without placental cause of death groups or minimal subdivision of this group are not useful in modern perinatal audit as loss of information occurs. The most frequent contributing factor was growth restriction. This illustrates the vital role of the placenta in determination of optimal fetal development. In the Tulip classification, mother, fetus and placenta are addressed together. The system has a clear defined subclassification of the placenta group, a low percentage of unknown causes and is easily applied by a multidisciplinary team. A useful classification aids future research into placental causes of IUFD.

The Tulip classification of perinatal mortality: introduction and multidisciplinary inter-rater agreement

OBJECTIVE

To introduce the pathophysiological Tulip classification system for underlying cause and mechanism of perinatal mortality based on clinical and pathological findings for the purpose of counselling and prevention.

DESIGN

Descriptive.

SETTING

Tertiary referral teaching hospital.

POPULATION

Perinatally related deaths.

METHODS

A classification consisting of groups of cause and mechanism of death was drawn up by a panel through the causal analysis of the events related to death. Individual classification of cause and mechanism was performed by assessors. Panel discussions were held for cases without consensus.

MAIN OUTCOME MEASURES

Inter-rater agreement for cause and mechanism of death.

RESULTS

The classification consists of six main causes with subclassifications: (1) congenital anomaly (chromosomal, syndrome and single- or multiple-organ system), (2) placenta (placental bed, placental pathology, umbilical cord complication and not otherwise specified [NOS]), (3) prematurity (preterm prelabour rupture of membranes, preterm labour, cervical dysfunction, iatrogenous and NOS), (4) infection (transplacental, ascending, neonatal and NOS), (5) other (fetal hydrops of unknown origin, maternal disease, trauma and out of the ordinary) and (6) unknown. Overall kappa coefficient for agreement for cause was 0.81 (95% CI 0.80-0.83). Six mechanisms were drawn up: cardio/circulatory insufficiency, multi-organ failure, respiratory insufficiency, cerebral insufficiency, placental insufficiency and unknown. Overall kappa for mechanism was 0.72 (95% CI 0.70-0.74).

CONCLUSIONS

Classifying perinatal mortality to compare performance over time and between centres is useful and necessary. Interpretation of classifications demands consistency. The Tulip classification allows unambiguous classification of underlying cause and mechanism of perinatal mortality, gives a good inter-rater agreement, with a low percentage of unknown causes, and is easily applicable in a team of clinicians when guidelines are followed.

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

Classifications of perinatal deaths have been undertaken for surveillance of causes of death, but also for auditing individual deaths to identify suboptimal care at any level, so that preventive strategies may be implemented. This paper describes the history and development of the paired obstetric and neonatal Perinatal Society of Australia and New Zealand (PSANZ) classifications in the context of other classifications. The PSANZ Perinatal Death Classification is based on obstetric antecedent factors that initiated the sequence of events leading to the death, and was developed largely from the Aberdeen and Whitfield classifications. The PSANZ Neonatal Death Classification is based on fetal and neonatal factors associated with the death. The classifications, accessible on the PSANZ website (http://www.psanz.org), have definitions and guidelines for use, a high level of agreement between classifiers, and are now being used in nearly all Australian states and New Zealand.

Evaluation of 239 cases of perinatal death using a fundamental classification system

OBJECTIVE

To classify 239 cases of perinatal death in a newly introduced classification system for underlying causes of perinatal death.

DESIGN

Prospective, descriptive.

SETTING

Dutch healthcare region Delft-Westland-Oostland (DWO).

MATERIALS AND METHODS

In 10 years (1983-1992), all cases of perinatal death with a birthweight above 500 g (n=239) were included into the study. We used a classification model based upon the underlying cause of death using simple principles of obstetrical and neonatal pathology. A team consisting of a gynaecologist, neonatologist and pathologist classified all cases of perinatal death into seven groups to determine the "most-probable" cause of death.

RESULTS

Birth trauma was seen in two cases (0.8%). Infections were seen in 16 cases (6.8%). Acute/subacute placental pathology in 77 cases (32.2%) and chronic placental pathology in 50 cases (21%). Bloodtype antagonism was seen in two cases (0.8%). Lethal congenital malformations in 55 cases (23%). Complications of pre-viable delivery in 20 cases (8.4%). Unclassifiable were 17 cases (7%): two cases could not be classified despite thorough investigation (1%) and 15 cases were lost for follow-up (6%).

CONCLUSIONS

Classification of perinatal death causes by using our fundamental classification system gives insight in the possible underlying causes of death. The results of such a classification can be used as guidelines for preventive measures in the future.