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    Fetus embryo

    Background

    The following protocol provides guidance in dealing with any intact baby delivered at <20 weeks gestation (or with a birthweight of <400g where gestational age is not known).

    The developing human is considered to be an embryo from conception until the end of the eighth week. From the ninth week until birth the developing human is considered to be a fetus.

    Embryos may be included in surgical specimens otherwise labelled ‘products of conception’. It is reasonable in these circumstances to perform basic measurements (such as weight, crown-heel or crown rump) together with a gross external examination (but no invasive procedure) without parental consent.

    In cases where more detailed or invasive examination is required, a consent process similar to that for fetuses delivered at <20 weeks gestation (or with a birthweight of <400g where gestational age is not known) should be undertaken.

    The word “baby” rather than “specimen” has been purposely used to convey the need for sensitivity which must be applied in this scenario. The parental needs and wishes must be the overriding priority in these cases.

    Legal requirements regarding consent, funeral, birth and death certification will vary in different jurisdictions, and may change with time.

    It is strongly recommended that a consent form signed by the requesting clinician and baby’s parents is received by the attending Pathologist before any examination or investigation is performed irrespective of the gestational age.

    It is recommended that the references provided are consulted for a greater understanding of fetus and embryo cases.1-7

    Receipt of consent, although not legally required for babies <20 weeks, is evidence that a discussion explaining the procedure and possible outcomes has taken place between the parents of the baby and the requesting clinician. Written consent in this situation also gives parents control over what types of examination are performed and what tissue can be taken.

    Before performing an examination on any baby <20weeks received in the anatomical department the intended assessment requested by the parents/clinician must be clearly stated and accompanied by the appropriate paperwork.

    If the appropriate consent is not received as is often the case, such as in ‘products of conception’ then only a minimal set of measurements similar to those listed below should be performed.

    Once a baby is ≥ 20 weeks gestation or has a birthweight of 400g where a gestational age is not known it is designated as a stillbirth. Strict legal requirements surrounding consent, birth/death certificates and funeral arrangements must be met.

    These requirements can vary between different territories and states5 and local requirements should be consulted before an examination takes place. A detailed discussion of these requirements is outside the scope of this protocol.

    In addition, sensitivity to parental needs to view the body and funeral arrangements including cultural and religious requirements should be considered in establishing dissection and processing protocols.

    Detailed guidelines for clinical practice in regard to perinatal mortality are available and should be consulted before processing performing an examination. Please see the references provided for more information (PSANZ1, RCP UK2,3 and ANZSA4). Refer to information on normal sizes and weight of babies for gestational period.7

    Stillbirth is defined as death prior to the complete expulsion or extraction from its mother of a product of conception of 20 or more completed weeks of gestation or of 400 g or more birth weight where gestation is not known. The death is indicated by the fact that after such separation the fetus does not breathe or show any other evidence of life, such as beating of the heart, pulsation of the umbilical cord, or definite movement of voluntary muscles1.

    The NSW Coroner’s Act 20098 definition of stillbirth is less specific; referring only to the definition given in the NSW Births, Deaths and Marriages Act9: “A stillborn child is defined to mean a child who is at least 20 weeks’ gestation, or with a body mass of at least 400 grams at birth, that exhibits no sign of respiration or heartbeat, or other sign of life, after birth”. Please note that the definition of stillbirth may vary between states and territories.

    Once consent for autopsy examination has been received the following should ideally accompany the baby:

    • Autopsy consent form and any religious/cultural requirements
    • Placenta (fresh, unfixed)
    • Clinical/obstetric history including relevant previous obstetric history
    • Copies of the death certificate or equivalent (if legally applicable)
    • Copies of all antenatal ultrasound reports
    • Copy of prenatal karyotyping results if available

    Record the patient identifying information and any clinical information supplied together with the specimen description as designated on the container. See overview page for more detail on identification principles.

    As a minimum the following measurements may be included without consent if the baby is intact:

    • Weight of baby (g)
    • Crown-heel length
    • Crown-rump length
    • Foot length
    • Head circumference
    • Chest circumference

    Refer to information on normal sizes and weight of babies for the gestational period7.

    Full external examination protocol

    A protocol for a full external examination with appropriate consent is detailed below.

    Record the patient identifying information and any clinical information supplied together with the description as designated on the container. See overview page for more detail on identification principles.

    All babies of 20 or more week’s gestation must have a full external examination. Those between 13 and 20 weeks will be assessed on a case by case basis, depending on the clinical circumstances. A specific autopsy procedure may be applicable if the baby arrives intact.

    Legal requirements regarding birth and death certificates will vary in different jurisdictions. 5 In addition, sensitivity to parental needs to view the body and funeral arrangements (if being organised by the family) should be considered in establishing dissection and processing protocols.1-6

    Detailed guidelines for clinical practice in regard to perinatal mortality are available and should be consulted before processing performing an examination. Please see the references provided for more information (PSANZ1, RCP UK2,3 and ANZSA4). Refer to information on normal sizes and weight of babies for gestational period.7

    Babies should not be placed in formalin but assessed in the fresh state if at all possible.

    • No
      • Non-routine fixation (not formalin), describe.
    • Yes
      • Special studies required, describe.
      • Ensure samples are taken prior to fixation.

    A protocol of ancillary tests should be established, including photographs, babygram and sample collection for cytogenetic analysis.

    • External photographs (with appropriate consent1) including the front, back and lateral with a close up of the face and side profiles of the head. Photograph any abnormal features or any area of uncertainty (e.g. gender) as to its significance (particularly if these procedures are not undertaken routinely). Note: it can be difficult to ascertain the gender on external examination and photographs are a useful record.
    • Babygram (full body X-ray) -may detect abnormalities, in particular skeletal abnormalities, otherwise undetectable on an external examination1
    • Cytogenetics. Amniocentesis prior to delivery1 is optimal where cytogenetic testing is critical.
    • A skin punch biopsy (with appropriate consent) may be used but it is an invasive procedure and results are not always possible on post-mortem material1. Umbilical cord tissue may be more appropriate and produce better test results1. In a full autopsy, a sample from the sternum may be useful as cartilage retains its viability for longer than skin.

    Inspect and dictate a macroscopic description of the baby +/- placenta and blood clot.

    Photograph the intact specimen if required.


    External Inspection

    Describe the following features of the body:

    Integrity

    • Intact
    • If disrupted, describe

    Sex

    • Male
    • Female
    • Indeterminate
    • Unable to be identified

    Skin surface appearance

    • Well-preserved
    • Macerated
    • Post-mortem artefact (including drying and mummification
    • Anomalies
      • Absent
      • Present e.g.
        • Digits
        • Palmar creases
        • Malformations, specify

    Size (mm) if intact

    As a minimum the following measurements should be included if the baby is intact:

    • Crown-heel length
    • Crown-rump length
    • Foot length
    • Head circumference
    • Chest circumference

    Weight (g)

    • Baby
    • Placenta (without cord, membranes and attached blood). See placenta protocols for more information.

    Placenta

    • Absent
    • Present -describe according to placenta protocols

    Attached blood

    • Measure in three dimensions
    • Note absence/presence of indenting (for evidence of chronic abruption)

    The approach to a full autopsy is beyond the scope of this manual. Suitable references for full autopsy examination are provided below (PSANZ1, RCP UK2,3 and ANZSA4).

    Videos demonstrating demonstrating aspects of perinatal autopsy are available for RCPA members after login via these links to the Education section of the website:

    Perinatal autopsy -incisions, brain removal and heart dissection

    Fetal heart dissection -second and third trimester (as clinical cases)


    Dissection

    No dissection is required.


    Internal Inspection

    Not required.


    Processing

    No processing required.

    Acknowledgements

    Dr Susan Arbuckle, Dr Ella Sugo and Prof Jane Dahlstrom for their contribution in reviewing and editing this protocol.


    References

    1. Flenady V, King J, Charles A, Gardener G, et al. for the Perinatal Society of Australia and New Zealand (PSANZ) Perinatal Mortality Group. PSANZ Clinical Practice Guideline for Perinatal Mortality. Version 2.2, Brisbane, 2009.
    2. The RCPath Working Party on the Autopsy. Guidelines on Autopsy Practice. Scenario 9: Stillborn infant (singleton), The Royal College of Pathologists, London, 2006.
    3. The RCPath Working Party on the Autopsy. Guidelines on Autopsy Practice. Scenario 10: Neonatal death. The Royal College of Pathologists, London, 2006.
    4. National Pathology Accreditation Advisory Council (NPAAC). Requirements for the Retention of Laboratory Records and Diagnostic Material, Australian Government, Department of Health and Ageing, Canberra, 2009.
    5. Khong TY. Ethical considerations of the perinatal necropsy. J Med Ethics 1996:22(2):111-114.
    6. Phillips JB, Billson VR, Forbes AB. Autopsy standards for fetal lengths and organ weights of an Australian perinatal population. Pathology. 2009;41(6):515-26.
    7. NSW Government. New South Wales Births, Coroners Act 2009 No 41. Parliamentary Counsel’s Office, Historical, Version valid from 16 Nov 2011 to 28 June 2012, viewed 12 Aug 2015.
    8. NSW Government. New South Wales Births, Deaths and Marriages Registration Act 1995 No 62. Parliamentary Counsel’s Office, Current, Version valid from 1 Jan 2014, viewed 12 Aug 2015.

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      26-Mar-2019
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