Products of Conception Tissues from Aborted/Miscarried Fetuses

BACKGROUND:

Fibroblast cultures are prepared from tissues obtained on products of conception or stillborn fetuses.

INDICATIONS FOR TESTING:

• To determine reason for fetal demise

• To confirm a chromosomal abnormality in an aborted fetus

SAMPLE REQUIREMENTS:

1. Fetal Tissue (Fetus 14 or more weeks of gestation):
   Send these tissues if possible:

   1. Cord blood-minimum 1 ml in a heparinized green top tube

   2. Skin and muscle 1 cm3 from lateral thigh

   3. Placenta 2 cm3 specimen including amnion at its surface obtained midway between the cord insertion and placental margin.

   In case of excessive maceration, provide tissue from muscle, kidney, heart or lung.

2. Products of conception:
   Send the entire gestational sack if possible. If not available, select tissue containing villi. Fetal parts are difficult to identify early in gestation, and most other tissues, including blood clots, membranes and decidua result in growth of maternal cells

SPECIMEN HANDLING:

1. Fetal Tissue:
   Place specimen in culture media with antibiotics (3X media). This media is available from the laboratory upon request. If media is not available, place on top of a sterile gauze pad moistened with water and place in a sterile container with lid. DO NOT SUBMERGE THE TISSUE IN SALINE OR WATER! DO NOT SEND THE ENTIRE FETUS!

2. Products of Conception:
   Place specimen in culture media provided by the laboratory, or send the specimen alone in a sterile container. Do not add saline or water.

Send either type of specimen to the laboratory the same day, by overnight mail, or refrigerate overnight and send the following day. Samples held up more than three days will not grow.

PROCEDURE:

The tissues are cleaned and dissected in the laboratory. Villi are identified and separated from the remaining tissues. The cleaned tissues are then dissociated with collagenase (fetuses), or collagenase and trypsin (villi). Single cell suspensions are grown in cultures, which are ready to be harvested between 4 and 21 days. The time depends on the condition of the specimen at the time of arrival.

Twenty metaphase cells are analyzed and 2 karyotypes are prepared from each routine specimen.

INTERPRETATION:

The analysis will detect fetal sex, and any gross abnormalities of the sex chromosomes or autosomes such as trisomies, monosomies, translocations, deletions and duplications. Deletions and rearrangements on the molecular level cannot be seen.

Molecular and biochemical testing can also be done on fresh or cultured cells.

RESULTS:

Results are presented according to the international standards for chromosomal nomenclature (ISCN), and a full explanation of the karyotype is provided. Any abnormal or variant results should be followed by genetic counseling.

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