Parental Balanced Translocation & Miscarriage

Parental balanced translocation is a factor in some cases of recurrent miscarriage.

UNDERSTANDING PARENTAL BALANCED TRANSLOCATION

Before discussing the connection between parental balanced translocation and miscarriage, it is first important to understand parental balanced translocation.

Normally, an individual has 23 pairs of chromosomes, which carry the genetic material that makes them who they are. One-half of the chromosomes come from the mother and the other half from the father. To do this, pieces of the chromosome pairs split so that the baby receives genetic material from each parent.

Translocation occurs when one piece of chromosome attaches to another bit of chromosome from a different pair. No genetic material is lost, the chromosomes sections are simply joined at the wrong position. Since the number of chromosomes is correct, but a portion of one of the chromosomes has attached incorrectly, it is referred to as a balanced translocation.

An estimated one in 560 people have a balanced translocation. It is not clear why balanced translocation occurs. It can be an inherited trait or can occur in a fetus even when neither parent is affected by the condition. New translocations can happen when sperm or egg cells are forming or immediately after fertilization. Most individuals with balanced translocation suffer no ill effects and are often undiagnosed until they suffer from problems with infertility.

Balanced translocation errors are diagnosed through karyotyping. Blood samples are collected from each parent and analyzed for translocation.

BALANCED TRANSLOCATION AND RECURRENT MISCARRIAGE

Many people with a balanced translocation have children. They may have a child with a normal chromosome pattern, or the child may have a balanced translocation just like the parent.

Natural conception and live birth is possible in cases of balanced translocation, but those with the condition may have more difficulty conceiving and are at a greater risk of recurrent miscarriage than those without it. When either the male or female partner has a balanced translocation, the risk of miscarriage increases to 20, 30 or even 50 percent. The greater the chromosomal imbalance in the fetus, the more likely the chance of miscarriage.

With each pregnancy, a parent with balanced translocation may produce a child with normal chromosomes or one with unbalanced chromosomes.

FERTILITY OPTIONS FOR COUPLE WITH BALANCED TRANSLOCATION

It is important that couples fully understand their options including the risks, cost and success rate. Treatment options include:

• Expectant management – sometimes call watchful waiting – is the least costly of the treatment methods. However, the risk of miscarriage can be as high as 50%
• Gamete or embryo donation – eliminates risks associated with balanced translocation but treatment costs are higher, and there is no genetic link to both parents
• IVF-PGD (preimplantation genetic diagnosis) – improves the chances for a success pregnancy and live birth and maintains a genetic link to parents. IVF and PGD are costly but can help ensure only embryos with no unbalanced chromosomal translocation are transferred. Studies have shown that PGD methods that use 24-chromosome screening offer a more reliable approach to reducing miscarriage rates for those with a balanced translocation

Contact your local URA clinic in Hasbrouck Heights, Hoboken, and Wayne, NJ for more information. Your friendly URA team will be happy to provide more information on parental balanced translocation.