Fetopsy in third trimester and stillbirth

Author: Mikael Häggström
Autopsy of a fetus in the third trimester (from 27 or 28 weeks of gestational age), as well as intrapartum stillbirth.

There are many variants, with the following being a suggestion:

Comprehensiveness

Factors supporting a relatively more comprehensive autopsy and/or report, particularly in the inclusion of negated findings:

• Lack of explanation from existing evidence. On the other hand, for example, upon finding an obvious aortic rupture, the rest of the autopsy is less relevant and may be relatively short.
• Double-reading: If your report is likely to undergo double reading by another pathologist before sign-out, it needs to be more detailed, because the doctor who will do the double-reading then knows that you have looked at those locations.
• Highly suspected locations, such as given from the referral.

On this resource, the following formatting is used for comprehensiveness:

• Minimal depth
• (Moderate depth)
• ((Comprehensive))

Other legend

<< Decision needed between alternatives separated by / signs >>
{{Common findings / In case of findings}}
[[Comments]]
Organs or important regions are in bold in the report example, but does not need to be in an actual report.

Preparations

• Read the fetopsy referral.

• {{If there is an indication for genetic testing, check if the placenta is available, and preferably take a sample while it is still fresh rather than in formalin.}}

• Confirm that there is a consent from the next of kin to perform the autopsy.
• (Go through the mother's medical records, at least if necessary aspects are not included in the referral. The most important aspects are:

• Maternal age/date of birth
• Relevant medical and family history, including consanguinity
• Maternal ((height, weight and)) BMI
• Previous pregnancies and deliveries:

• Previous pregnancy losses and any pathology results thereof
• Any malformations, growth restrictions or other complications

• History of current pregnancy, including:

• Gestational age
• Any antenatal infection screening results
• Any abnormal findings from ultrasound or other antenatal investigations
• Any hypertension, bleeding, fever or membrane rupture
• Most recent events leading up to intrauterine death and/or delivery
• Time of delivery, and first recorded absence of fetal heartbeat such as ultrasound
• Delivery: Mode, complications and any instrumentation used
• Any attempted resuscitation.)

{{If skeletal dysplasia is suspected, apply X-ray or CT.}}

In the autopsy room, before starting examination:

• Bring a camera to document relevant findings.
• Use protective wear, generally according to local practice. Do any knots before putting on gloves for better dexterity.
• Confirm the identity of the fetus, often by the mother's identity details.

External examination

Components:

• Measure body weight, crown-rump length, crown-heel length, foot length and occipito-frontal circumference.
• Determine nutritional status/soft tissue and muscle bulk
• Inspect skin for any maceration, local/generalised oedema, pallor, meconium staining
• Determine any overall dysmorphic features, evidence of trauma or other lesions
• Orifices for patency, including choanae
• Confirm palatal fusion

Report

Example report for external examination

The <<specimen/body>> is received fresh and consists of a phenotypically <<male/female>> fetus weighing __ grams and measuring as follows: crown-rump length __ cm, crown-heel length __ cm, head circumference __ cm, and foot length __ cm. The skin is tan-red and smooth. There are areas of desquamation on __. The total area of desquamation comprises approximately __% of body surface. The nares, oral cavity and anus are patent. The eyes and ears are of normal shape, size and positioning. A cleft lip/palate is not present. There are no craniofacial dysmorphologies. The neck and back appear within normal limits, with a normal curvature. The chest is symmetrical. The upper and lower extremities show normal musculoskeletal development. The bilateral upper/lower extremities are grossly normal, each with five digits. The palmar/plantar creases are normal. The chest measures __ in circumference. The abdomen measures __ in circumference, with a __ cm portion of attached soft pink umbilical cord. There are no external congenital anomalies. ((ADDITIONAL COMMENTS: Two identification tags are present, one on the left leg and the other on the cloth in which the body was wrapped. Digital photographs are taken.))

Internal examination

• Make a longitudinal skin incision on the front of the body, typically T- or Y-shaped.
• Measurement the thickness of the subcutaneous fat over the sternum.

Central nervous system (CNS)

The skull is opened by a median posterior or transverse scalp incision. Components:

• Inspect falx and venous sinuses for injury and/or meningeal hemorrhage (especially in intrapartum

death)

• Look for any skull fracture or occipital osteodiastasis (at least in intrapartum death)
• Look for any spinal injury by a posterior approach (at least in intrapartum death)
• If a CNS malformation is suspected, examine the posterior fossa structures by a posterior approach.
• Inspect the gyral pattern

• ((Remove the brain under water and perhaps in dura (especially with marked autolysis), for weighing and further assessment of the gyral pattern.))

Other internal organs

Macroscopic predictors of duration between fetal death and delivery of fetuses of at least 28 weeks of gestational age

Finding	Duration
Desquamation ≥1 cm	≥6 h
Desquamation of the face, back, or abdomen	≥ 12 h
Desquamation ≥ 5% of the body Desquamation 2 or more of 11 zones	≥ 18 h
Mummification	≥2 weeks

Including:

• Umbilical arteries and vein, and ductus venosus
• Heart and great vessels, by initial in situ examination
• Thoracic and abdominal organs, by initial in situ examination.
• Dissect along the diaphragm to detect any organ herniation.
• ((Dissect up to the larynx to inspect the thyroid and detect any tracheoesophageal fistulas.))
• Weigh internal organs (minimum: thymus, heart, lungs, liver, kidneys, adrenals, spleen and brain)
• The placenta:

• Trimmed weight (without extraplacental membranes and cord)
• Dimensions of the placenta (width in two planes and thickness)
• Fetal surface: appearance, any thrombosis of chorionic vessels
• Maternal surface: completeness, craters
• Slicing at approximately 1 cm intervals to evaluate parenchyma for color and focal changes.

• The umbilical cord

• Measure length, diameter, and number of vessels.
• Note the insertion into the placental disc

Look for any coiling or lesions

• Membranes

Report

A standard Y-incision is performed to open the thoracic and abdominal cavities. The pleural and peritoneal cavities contain a minimal amount of serous fluid. In situ examination of the organs reveals normal positioning, to include the following: the thyroid is overlying the trachea; the thymus is overlying the anterior mediastinum; and the right and left lungs show proper lobation with the bases resting at the level of the heart apex. The heart appears normal in size and shape. The heart apex points towards the left. The great vessels are in their normal anatomical position and originate from the right and left ventricles. Opening of the heart reveals a patent foramen ovale and ductus arteriosis, and normal ventricular formation. There is no evidence of atrial septal defect, ventricular septal defect or coarctation of the aorta. The diaphragm is intact. The larynx is unremarkable. There is no tracheoesophageal fistula. The esophagus is intact and appropriately located. The stomach is unremarkable. The bowel shows normal rotation and fixation to the peritoneal wall. No intestinal atresia, duplication or congenital diverticulum is identified. The appendix is located in the right iliac fossa. The liver is tan-brown, and cut sections show homogeneous parenchyma without cysts or masses. An unremarkable gallbladder is attached at the liver undersurface. The spleen is located in the left hypochondrial area. The pancreas and kidneys are identified within the retroperitoneum, and they display normal fetal lobations. Cut sections show a well-demarcated corticomedullary junction bilaterally. The adrenals are located at the upper renal poles. The ureters appear straight, non-dilated and insert into the bladder in a normal fashion. The internal genitalia consists of << the uterus, fallopian tubes and ovaries / two undescended testes >>. The cranium is opened to reveal an unremarkable soft brain. The cerebral hemispheres each displays a lateral ventricle and homogenous white brain matter. The cerebellum is bilobed and located inferior to the cerebral hemispheres and superior to the foramen magnum. No gross central nervous system malformation is identified. ( The brain is fixed in toto in formalin prior to further examination.) Organ weights are as follows: heart __ gms, right lung __ gms, left lung __ gms, liver __ gms, right kidney __ gms, left kidney __ gms, right adrenal __ gms, left adrenal __ gms, thymus __ gms, brain __ gms, spleen __ gms. Representative sections are submitted for microscopic examination in __ cassettes.

Microscopic examination

A major aim of the microscopic examination is to estimate the duration between the time of fetal death and the delivery of the fetus. Following are parameters of fetuses of 28 weeks of gestational age or older:

Finding	Duration
Kidney: Loss of tubular nuclear basophilia	≥4 h
Liver: Loss of hepatocyte nuclear basophilia	≥ 24 h
Myocardium: Loss of nuclear basophilia of inner half	≥ 24 h
Myocardium: Loss of nuclear basophilia of outer half	≥ 48 h
Bronchus: Loss of epithelial nuclear basophilia	≥ 96 h
Liver: Maximal loss of nuclear basophilia	≥ 96 h
Gastrointestinal tract: Maximal loss of nuclear basophilia	≥1 week
Adrenal: Maximal loss of nuclear basophilia	≥1 week
Trachea: Loss of nuclear basophilia of chondrocytes	≥1 week
Kidney: Maximal loss of nuclear basophilia	≥4 weeks
Intravascular karyorrhexis of the placenta	≥6 h
Placental multifocal luminal abnormalities of stem vessels: multifocal	≥ 48 h
Placental extensive luminal abnormalities of stem vessels: extensive	≥ 14 days
Extensive villous fibrosis	≥ 14 days

Example report

HEART: Sections of the heart show cardiac muscle with postmortem autolytic changes and loss of nuclear basophilia in the inner half {{as well as the outer half}} of the myocardium consistent with fetal demise approximately ___ hours prior to delivery. LUNGS: Sections of the lungs show alveolar stage of development consistent with __ weeks of gestational age. LIVER AND GALLBLADDER: Sections show normal liver architecture with extensive autolysis and congestion without significant histopathologic changes. Extramedullary hematopoiesis is present. Section of gallbladder shows extensive autolytic mucosal epithelial cells. SPLEEN: Section of the spleen shows primitive red and white pulp with red pulp congestion, hemosiderin laden macrophages and postmortem autolytic changes. THYMUS: Section shows benign lymphoid tissue with Hassall’s corpuscles with scattered calcifications. TRACHEA AND THYROID: Sections demonstrate benign cartilage with possible thyroid gland with autolysis. UMBILICAL CORD: Section shows three vessel umbilical cord with arteritis and autolytic changes. BILATERAL KIDNEYS: Sections of both kidneys demonstrate normal architecture with autolysis, without significant histopathologic changes. There is preserved nuclear basophilia consistent with fetal demise approximately ___ hours prior to delivery. ADRENAL GLANDS: Sections of the adrenal glands demonstrate minimal preserved cortical parenchyma with extensive autolysis of medulla and part of cortex. BRAIN: Sections of the brain show significant autolysis. Subarachnoid hemorrhage is not seen, however marked vascular congestion of meningeal small blood vessels is seen in the parieto-occipital area. Congested blood vessels are seen in all sections of the brain. No evidence of hemorrhage within the brain parenchyma is seen. There is no evidence of infection.

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