factor V Leiden mutation (recurrent miscarriage,prevention)

Last reviewed 01/2018

There is some limited evidence that thrombophylaxis is effective in preventing recurrent miscarriages in women with factor V Leiden mutation.

Younnis et al (1) undertook a study to determine the effect of thrombophylaxis on pregnancy in women carrying the factor V Leiden mutation with a history of recurrent miscarriage:

• the trial was an uncontrolled intervention trial
• 56 women with a history of 2 or more consecutive pregnancies were enrolled in the study - 20 women were found to have activated protein C resistance (of the 20, 12 women were found to have factor V Leiden mutation)
• of the 12 women with factor V Leiden mutation, 7 went on to conceive - 6 women had thrombophylaxis with low dose aspirin and low molecular heparin; 1 woman had low dose aspirin alone; of the 7 pregnancies - 5 resulted in live births and 2 were early miscarriages (71% live birth)
• these 7 women previously had had 36 previous pregnancies between them, of which 29 resulted in miscarriage (19% live birth)

This study appears to show that thrombophylaxis improves pregnancy outcome in women with factor V Leiden mutation. However because of the numbers of women involved in the study and the uncontrolled design, the study results have to be considered with caution.

Reference:

• 1) Younnis JS, Ohel G, Brenner B et al (2000). The effects of thromboprophylaxis on pregnancy outcome in patients with recurrent pregnancy loss associated with factor V Leiden mutation. Br J Obstet Gynaecol, 107, 415-9.