Loss of Pregnancy
Reasons for Testing
After the loss of a pregnancy, most parents want to know why it happened and whether anything could have prevented it.
In approximately 50% of cases, the cause can be a random genetic problem in the developing baby, and there was nothing that could have been done to prevent it. The majority of women who have one miscarriage go on to have an uneventful next pregnancy
Testing can provide diagnosis of the current loss as well as potential recurrence risks for chromosomal problems in a future pregnancy. Undertaking testing can help bring about closure for the current loss and, if a genetic reason for the loss can be found, have a significant impact on the management of any future pregnancies.
Tests offered for loss of pregnancy
Conventional G-banded metaphase analysis (cytogenetics) can be performed on fetal tissue or products of conception. The tissue is cultured and metaphases obtained. A complete analysis (looking at all chromosomes) is undertaken. This is recommended for women who have experienced 3 or more fetal losses.
The results of this test can take up to 1 month to become available.
FISH can also be performed where we look specifically at copy number of chromosomes most commonly involved in pregnancy loss. In practice this means that we look at the sex chromosomes X and Y, and chromosomes 13, 18 and 21. This might be the preferred option for woman who experience their first fetal loss. The results of this test are available within 3 days.
Please note: In some instances it may be desirable to perform both karyotyping and FISH on the products of conception.