3 - Recurrent miscarriage

Summary

Recurrent miscarriage is defined as loss of three or more consecutive pregnancies. It affects 1% of all women. This incidence is greater than that expected by chance alone as, based on a 10–15% risk of spontaneous miscarriage among clinically recognised pregnancies, this would be expected to be around 0.34%. So it is understandable that only a small proportion of women will be found to have an underlying aetiology identified as the cause for recurrent miscarriage. Recurrent miscarriage could be further labelled as ‘primary recurrent miscarriage’, where women have had no successful pregnancies, or as secondary recurrent miscarriage, where women miscarry repetitively after a successful pregnancy or pregnancies.

Aetiology

UNKNOWN OR IDIOPATHIC

Almost 50% of all recurrent miscarriages remain unexplained despite investigations. Most women who have two or three miscarriages have nothing wrong with them and this is the justification for not undertaking tests and investigations routinely before three consecutive miscarriages. Any drug treatment in this group would be empirical and the mainstay of management of these women is based upon emotional support supplemented by ultrasound scan in early pregnancy, which gives success rates of between 70% and 80%.