The perinatal autopsy: a contemporary approach

Guidelines for Investigating Stillbirths: An Update of a Systematic Review

OBJECTIVE

To identify formal, publicly available guidelines for stillbirth investigation and to identify the most appropriate clinical practice guideline (or component of a guideline) for use in Alberta.

METHODS

A systematic literature search was conducted to identify primary and secondary research studies published between January 1985 and August 2006 and formal, publicly available guidelines on the subject of stillbirth investigation. The Cochrane Library, PubMed, EMBASE, CINAHL, HealthSTAR, Science Citation Index, BIOSIS, and the NHS and CRD databases were searched. The methodological quality of the selected primary research studies was assessed according to specific criteria.

RESULTS

All six of the publicly available clinical practice guidelines selected for this review outlined similar steps in the stillbirth investigation but differed about which tests to include and which components should be core or additional investigations. They agreed on including several elements for routine investigation, such as complete autopsy and detailed examination of the cord and placenta. Of 61 retrieved primary research studies, only seven met the inclusion criteria. No studies compared the value of specific guidelines. Although reviewed evidence highlights the value of fetal autopsy and placental examinations as integral components of stillbirth investigation, the value of other components is still not clear.

CONCLUSIONS

No firm scientific judgement could be made about which clinical practice guideline for stillbirth investigation is the most appropriate or which components are essential. Currently here is no generally accepted reference guideline for stillbirth investigation. Fetal autopsy and placental examination remain important components, assuming the postmortem examination is of high quality. These data may be helpful in counselling parents who are considering whether or not to consent to a postmortem examination.

My approach to performing a perinatal or neonatal autopsy

An opportunity to determine the cause of death, factors that may have a role in it, and the extent and cause of malformations is provided by perinatal autopsy. The family may be assisted in finding closure after the death of their infant by the information obtained. Insight into classifying infants appearing normal into one of three groups, small, appropriate and large for gestational age, has been provided, as each group tends to have specific causes of death. In infants with congenital anomalies, patterns of malformation may lead us to the diagnosis. An accurate diagnosis is required to provide counselling for a subsequent pregnancy.

Evaluation of a protocol for postmortem examination of stillbirths and neonatal deaths with congenital anomalies

A study was conducted on 75 perinatal deaths with congenital anomalies through clinical, radiographic, cytogenetic, and autopsy evaluation, and the diagnoses of 72 patients (96%) were determined. In 11 patients with chromosomal anomalies, the cytogenetic study was sufficient to determine the diagnosis and the reproductive risk. In these cases, the value of the autopsy results resided above all in the description of the clinical variability. Radiographic evaluation was the best method to establish a diagnosis of skeletal dysplasias (14.7%). Furthermore, the X-rays showed small skeletal defects which are difficult to see on dissection. The clinical genetic evaluation with a detailed description of the phenotype and anthropometric exam, performed by a clinical geneticist, and the autopsy with gross and microscopic evaluation, facilitated the diagnoses of 50 cases (66.7%). We concluded that, in perinatal death with congenital anomalies, the teamwork of clinical geneticists and fetal pathologists increases the probability of determining the etiological diagnosis. This is essential to define the parents' reproductive risk, thus contributing to primary prevention of congenital anomalies.

Value of the perinatal autopsy: critique

In consenting to a perinatal autopsy, the primary motive of parents may be to find the exact cause of death. A critical review on the value of perinatal autopsies was performed to see whether parents could be counseled regarding their main motive. A literature search was performed in MEDLINE, EXCERPTA MEDICA, and the Cochrane library. We evaluated the value of the autopsy by comparing the clinical and autopsy diagnoses in stillbirths, neonatal deaths, and therapeutic terminations. Clinicopathologic concordance was divided into four categories: (1) change in diagnosis, (2) additional findings, (3) complete confirmation, and (4) inconclusive. We sought information on factors that may influence the value of perinatal autopsies: the type and definitions of perinatal loss; autopsy rate; level of hospital; expertise of pathologists; autopsy protocol used; whether patients were inborn or referred; and antenatal diagnosis. From the 27 articles that met our review criteria, the autopsy revealed a change in diagnosis or additional findings in 22% to 76% of cases. If confirmation of clinical findings is included, then the value of the perinatal autopsy was as high as up to 100%. Factors that could influence this rate were reported variably by investigators. When centers report their experience of the value of the perinatal autopsy, information on the factors that may influence their reports should be provided as well. Clinicians can confidently advise parents of the usefulness of the perinatal autopsy in ascertaining the cause of death or for counseling their future pregnancies.

Fetal autopsy: a review of recent developments

OBJECTIVE

To analyze recent changes in fetal autopsy in response to developments in prenatal medicine.

METHOD

During the period 1988 through 1997, 783 fetuses (75% induced abortions, 18% spontaneous abortions, and 7% stillbirths, all between the 12th and 40th week of gestation) with prenatally diagnosed congenital malformations and chromosomal aberrations were analyzed. We divided the autopsies into two periods: period A (1988-92, n=370) and period B (1993-97, n=413). All fetuses were analyzed before completion of 20 weeks of gestation. The malformations of the organ systems were presented according to their frequency for fetuses independent of the weeks of gestation.

RESULTS

An autopsy was performed prior to the completion of 20 weeks of gestation for 24% of the fetuses in period A and 45% in period B (P<0.0001). The number of diagnosed congenital heart malformations increased from 16% in period A to 23% in period B. The number of congenital heart malformations before completion of 20 weeks of gestation was only 21% in period A as compared to 42% in period B.

CONCLUSIONS

In period B, clinical questions were raised in a more concrete form and ultrasound images gave more detailed information than in period A. Access to prenatal findings prior to postmortem examination has helped investigators to develop a specific, clinically oriented, autopsy strategy based on the prenatal findings which makes it possible to diagnose very small malformations and to select sectional planes of special interest. The use of an interdisciplinary database is required for communication.

Role of the autopsy in congenital cystic hygroma

Sixteen cases of congenital cystic hygroma were identified through a retrospective review of surgical pathology and autopsy records. Tissue sections of the cystic hygromas were available in 10 cases and were examined histopathologically and for reactivity to factor VIII antiserum. Of 13 cases with ultrasound examinations, cystic hygroma was diagnosed prenatally in 9. In 11 cases with successful karyotyping, six were 45, X. Histopathologic observations of lymphatic vascular architecture were apparent in 10 cases, and immunoreactivity of the endothelium to factor VIII antiserum was preserved regardless of the degree of autolysis.