Genetic Diagnosis

Identification of possible hereditary abnormalities in prospective parents that may affect their offspring.
"A recognized cause of repeated first trimester pregnancy losses is genetic abnormality." [Examination of chromosomes or] "Karyotyping of couples will reveal that 3-8% have some abnormality, most frequently a balanced chromosomal rearrangement, a translocation. Other abnormalities encountered include sex chromosome mosaicism, chromosome inversions and ring chromosomes. Besides spontaneous abortions, these abnormalities are associated with a high risk of malformations and mental retardation. It is important to emphasize that karyotyping uncovers only a percentage of those pregnancies lost due to genetic abnormalities. There may be single gene defects that are not manifested by chromosomal abnormalities.

"…If the karyotype is abnormal, nothing can be done to lessen the chances of another abortion; however, with most abnormalities there is a 50% chance the next pregnancy will be normal. Amniocentesis or chorionic villus biopsy should be encouraged in any pregnancy in couples with previous abnormal karyotype because of the risk of an abnormal child. Today, couples with serious high risk abnormalities may elect to pursue a pregnancy by means of donor sperm or in vitro fertilization with donor oocytes (or both)."

(Excerpts from: Clinical Gynecologic Endocrinology and Infertility. Speroff, Glass, and Kase. Lippincott Williams & Wilkins. 1999)