Factor V Leiden and recurrent miscarriage-prospective outcome of untreated pregnancies.
BACKGROUND
Some cases of recurrent miscarriage and later pregnancy complications have a thrombotic basis. Factor V Leiden is a common thrombophilic mutation.


METHODS
The prospective outcome of untreated pregnancies amongst 25 women heterozygous for the Factor V Leiden allele who had a history of either recurrent early miscarriages only (three or more miscarriages at <12 weeks gestation; n = 19) or of late miscarriage (>12 weeks gestation; n = 9) was studied. Control groups of women with a similar pregnancy history but who had a normal Factor V genotype were also studied.


RESULTS
The live birth rate was significantly lower amongst women with a history of recurrent early miscarriage who carried the Factor V Leiden allele (6/16; 37.5%) compared with that amongst those with a normal Factor V genotype (106/153; 69.3%; odds ratio 3.75, 95% confidence intervals 1.3-10.9). The live birth rate was 11.1% (1/9) amongst those with a history of late miscarriage carrying the Factor V Leiden allele and 48.9% (22/45) amongst those with a normal Factor V genotype.


CONCLUSIONS
Attention should be directed at screening women with recurrent miscarriage associated with placental thrombosis for Factor V Leiden and a policy of targeted thromboprophylaxis during future pregnancies should be assessed in the form of a randomized controlled trial.
Rai
R
R
Department of Reproductive Science, Faculty of Medicine, Imperial College of Science, Technology and Medicine , St Mary's Hospital NHS Trust, London, UK. r.rai@ic.ac.uk
Backos
M
M
Elgaddal
S
S
Shlebak
A
A
Regan
L
L
D000026:Abortion, Habitual / Q000235:genetics*; D000328:Adult; D001723:Birth Rate; D005165:Factor V / Q000235:genetics; D005260:Female; D005838:Genotype; D005865:Gestational Age; D006801:Humans; D008499:Medical Records; D008875:Middle Aged; D011247:Pregnancy; D011256:Pregnancy Outcome; D011446:Prospective Studies; D012016:Reference Values
C095381:factor V Leiden; D005165:Factor V