Habitual miscarriage is defined whenever any woman has had three consecutive miscarriages. Recurrent miscarriage is a distressing condition for all affected women. There are potential treatment options and all such women need to be investigated.
Miscarriage is common and occurs in about 15% of all early pregnancies. Fortunately recurrent miscarriage is not common. After three consecutive pregnancy losses the recurrence rate is 30%.
It is essential to investigate such women to try and identify any underlying problems that might allow treatment options to decrease recurrence rates.
Chromosome problems are the commonest cause for miscarriages.
Aneuploidies are chromosome problems where chromosomes are either added or deleted.
The following are aneuploidies, which are potentially compatible with life:
- Down Syndrome
- Edwards Syndrome
- Patau Syndrome
- Turners Syndrome
Other aneuploidies are not compatible with survival. Other chromosomal abnormalities do not involve a problem with chromosome numbers but instead with gene defects. Sometimes multiplication and deletion of chromosome sequences may also occur which can affect the fetus.
In general it is not possible to prevent chromosome problems, as they are most often-random events and unpredictable.
Occasionally some women or their husbands may carry a balanced translocation where a balanced rearrangement of genetic material exists in their cells which does not affect them but which increases the rate of chromosomally abnormal pregnancies.
Rarely some women may have a low order Mosaic of a chromosome problem such as Turners Syndrome. Mosaicism is the situation where certain cells contain normal chromosomes whilst other cells do not.
Thrombophilias and connective tissue disorders mediate their effects by damaging blood vessels and increasing the risks of thrombosis. This in turn may increase the risk of miscarriage.
Depending on the individual case these problems can be treated with either Low Dose Aspirin (LDA) or Clexane (injectable blood thinner).
Uterine shape abnormalities are difficult to treat and may involve surgical resection of uterine septa or fibroids. These treatments can result in scarring within the uterus, which can cause future potential problems.
It is appropriate when no cause for miscarriage can be identified to treat such patients with a combination of vitamins and blood thinners.
It is also wise to review such patients with weekly scans to confirm fetal viability on a regular basis to give the patients reassurance that all is well with their pregnancy.