Fetal autopsy: a review of recent developments

Autopsy Findings of Central Nervous System Anomalies in Intact Fetuses Following Termination of Pregnancy After Prenatal Ultrasound Diagnosis

OBJECTIVES

Central nervous system (CNS) anomalies are the second most frequent category of congenital anomalies after congenital heart defects (CHDs). In this study, the aim was to investigate the distribution of different CNS anomalies with associated anomalies and karyotype in a fetal autopsy population of terminated pregnancies over a 30-year period and to correlate the ultrasonographic diagnoses of CNS anomalies with autopsy findings.

MATERIALS AND METHODS

This study includes 420 intact fetuses with CNS anomalies terminated at gestational ages 11^+ 0 to 33^+ 6 over a 30-year period from 1985 to 2014. An ultrasound (US) examination was performed at the National Centre for Fetal Medicine, St. Olavs Hospital, Trondheim. The autopsies were performed at the Department of Pathology at the same hospital or a collaborating hospital. The anomalies were subcategorized according to the classification by the World Health Organization.

RESULTS

Neural tube defects such as anencephaly (22.4%, 107/477) and spina bifida (22.2%, 106/477) constituted the most common CNS anomalies, followed by congenital hydrocephalus (17.8%, 85/477). In total, the karyotype was abnormal in 21.0% of all termination of pregnancies (TOPs), with trisomy 18 as the most frequent abnormal karyotype. CHDs, skeletal anomalies, and urinary anomalies were the most common associated organ anomalies. Throughout the study period, there was full agreement between US and postmortem findings of CNS anomalies in 96.9% (407/420) of TOPs.

CONCLUSION

In this study of autopsy findings of CNS anomalies in intact fetuses terminated after prenatal US diagnosis, neural tube defects were most common. About half of the fetuses had isolated serious CNS anomalies, while the other half were CNS anomalies associated with structural and/or chromosomal anomalies. The prenatal US diagnoses were in good concordance with autopsy findings. In particular, due to challenges of diagnoses made early in pregnancy, it is necessary to continue the validation practice.

Comparison between prenatal ultrasound and postmortem findings in fetuses and infants with developmental anomalies

OBJECTIVE

To determine if postmortem examinations of fetuses and infants change the diagnosis obtained at prenatal ultrasound and affect counseling of future pregnancies, and if there has been a change over recent years in the accuracy of prenatal ultrasound diagnosis.

METHODS

This was a retrospective review of 455 autopsies of fetuses and infants with developmental anomalies performed at Trondheim University Hospital between 1995 and 2004 and with a prenatal ultrasound examination performed at a tertiary referral center. The routine ultrasound examinations were performed by specially trained midwives and obstetricians, referral scans by fetal medicine experts and autopsies by consultant pathologists with experience in perinatal pathology. The results of this study were also compared with those of a previous similar study performed between 1985 and 1995, with fetuses and infants coming from the same population and diagnosed at the same center.

RESULTS

Of all cases analyzed during the study period, there was complete agreement between prenatal ultrasound and postmortem findings in 84% (384/455), i.e. prenatal ultrasound diagnoses were supplemented by postmortem examinations in 16% (71/455). Autopsy findings in four of these cases influenced further counseling. There was agreement regarding the main diagnosis in 98% (445/455) of cases. In the previous 10-year period, there was complete agreement in 75% and the main diagnosis was correct in 90% of cases. These differences between the two time periods were statistically significant (P = 0.0004 and P < 0.0001, respectively). The most frequent defects involved the central nervous system, heart and urinary tract. For these defects, detection rates for the main diagnoses were significantly better in 1995-2004 compared with in the previous 10-year period (P = 0.0125, P = 0.0111 and P = 0.0241, respectively).

CONCLUSION

The accuracy of prenatal sonographic detection of developmental anomalies has increased in recent years. However, postmortem examination is still necessary to verify or improve the prenatal diagnosis and may influence future counseling.

Correlation between prenatal ultrasound and fetal autopsy findings in fetal anomalies terminated in the second trimester

OBJECTIVE

The aim of the study was to compare the consistency of major/minor fetal anomalies detected by second trimester prenatal ultrasound examination with the findings in fetal autopsies following the termination of pregnancy (TOP) in the second trimester.

DESIGN

In a 4-year long prospective study, 107 second-trimester TOP was performed due to fetal malformation diagnosed by second trimester-ultrasound examination at a tertiary referral center. Ultrasound findings were compared with fetal autopsy findings.

RESULT

Of the 107 cases with major fetal anomalies diagnosed by prenatal ultrasound, 49% had central nervous system anomalies, 23% had kidney and urinary tract anomalies, 11% had congenital heart disease. All of these major anomalies leading to TOP were confirmed by fetal autopsy (100% success rate in major anomalies). Overall success rate in prenatal ultrasound for major and minor anomalies was 77%. The percentage of additional minor anomalies detected in fetal autopsies was 20%. Three percent of the minor anomalies detected by prenatal ultrasonography could not be confirmed during autopsy. Chromosomal anomalies were detected in 9 (16%) out of 57 cases.

CONCLUSION

Evaluation of fetal autopsies following TOP enables diagnosis of pathologies undetected by prenatal ultrasound alone, leading to better preconceptional counseling for subsequent pregnancies.

Clinicopathological evaluation of 59 cases of fetal death

OBJECTIVE

The purpose of this study has been assessing the determinants of stillbirth among the newborns of the Verona University Obstetrics Department.

MATERIALS AND METHODS

A total of 59 stillbirth cases, observed between January 2000 and June 2006, were retrospectively studied. WHO definition for stillbirth was adopted as the inclusion criterion. Clinical files, feto-maternal laboratory data, feto-placental pathology findings as well as delivery mode and circumstances were all systematically reviewed.

RESULTS

The 59 observed cases correspond to an incidence of 9.8 stillbirths/year, which, considering the institutional delivery rate, correspond to 5.4 cases per 1000 births. Frequent relevant conditions associated with stillbirth were intrauterine growth restriction (15.2%), congenital fetal anomalies (13.5%), various maternal diseases (21.0%); no cause of fetal demise could be found in 10/59 (17.0%) cases, which were classified as unexplained. Most deliveries were successfully induced with prostaglandins except 11 cases (19.0%) which required a C-section due to severe maternal conditions associated with the fetal loss.

CONCLUSION

Thorough investigation of each individual stillbirth case, by means of an integrated study protocol, along with the Pathologist's close collaboration, allows identification of a likely cause in the majority of cases. Better knowledge of unexpected fetal loss is the premise for better parental counselling and for prevention of recurrences.

Ras-related signaling pathways in valve development: ebb and flow

Congenital heart defects affect approximately 1 in every 100 live births, and deficits in the formation of the mitral, tricuspid, and outflow tract valves account for 20-25% of all cardiac malformations. Mutations in genes that affect Ras signaling have been identified in individuals with congenital valve disease associated with Noonan syndrome and neurofibromatosis type 1. Dissection of Ras-related signaling pathways during valvulogenesis provides seminal insight into cellular and molecular mechanisms that contribute to congenital heart disease.