More on: factor V Leiden and prothrombin G20210A polymorphisms as risk factors for miscarriage during a first intended pregnancy: the matched case-control "NOHA First" study

To Test or Not to Test: Routine Thrombophilia Diagnostic Screening of Women with Reproductive Failures

BACKGROUND

Recurrent reproductive failure is a global health issue affecting a significant number of women. Thrombophilias have been implicated as a possible cause. Inherited thrombophilias include a single nucleotide variant on factor V Leiden and prothrombin.

OBJECTIVE

The aim of this study was to evaluate the association between the following single nucleotide variants: factor V Leiden (c.1601G>A), the prothrombin gene (c.*97G>A) and the reproductive failure in the Polish population.

METHODS

The study was conducted in a group of 545 patients with recurrent pregnancy loss, RPL (≥2 miscarriages), and in a group of 641 patients with infertility. The distribution of genotypes for the selected variants were determined by RFLP-PCR and by the real-time PCR method.

RESULTS

A variant of the F5 gene was found in 5.14% of patients with RPL and in 6.08% of infertile women. A variant of the F2 gene was identified in 0.73% of patients with RPL and in 2.03% of women with infertility. The frequency in the study groups did not differ from that in the general population. No association between the studied variants of the F5 gene or the F2 gene and the predisposition to reproductive wastage was found.

CONCLUSIONS

Recommendations for routine thrombophilia testing in women with recurrent miscarriages should be revisited. The decision regarding testing should be made individually depending on additional factors indicating an increased risk of venous thromboembolism.

Factor V Leiden mutation: a treatable etiology for sporadic and recurrent pregnancy loss

OBJECTIVE

We hypothesized that the thrombophilic G1691A factor V Leiden (FVL) gene mutation was a common, significant, and treatable cause of sporadic and recurrent pregnancy loss (RPL).

DESIGN

We compared the frequency of the FVL mutation in 141 women with >or=1 pregnancy and 1 sporadic pregnancy loss (308 live births, 141 pregnancy losses), 44 women with >or=1 pregnancy and >or=3 pregnancy losses (105 live births, 180 pregnancy losses), and 638 women with >or=1 live birth pregnancy and 0 pregnancy loss (1553 live births).

SETTING

Outpatient Clinical Research Center.

PATIENT(S)

A total of 823 caucasian women with consecutive measures of the FVL mutation.

MAIN OUTCOME MEASURE(S)

We used polymerase chain reaction techniques to characterize the thrombophilic FVL G1691A gene mutation.

RESULT(S)

Of the 638 controls, 47 (7.4%) had FVL heterozygosity versus 16 heterozygous and 2 homozygous FVL cases (18/141, 12.8%) in 141 women with 1 sporadic pregnancy loss versus 9/44 RPL cases (20.5%, 8 heterozygous and 1 homozygous FVL). The FVL frequency in cases with 1 sporadic pregnancy loss (18/141, 12.8%) did not differ from RPL cases (9/44, 20.45%).

CONCLUSION(S)

After unexplained sporadic pregnancy loss, as well as after RPL, to provide the option to prospectively optimize subsequent live birth outcomes with low-molecular-weight heparin thromboprophylaxis, we suggest that measurements be done of the FVL mutation, a treatable etiology for sporadic pregnancy loss as well as for RPL.

Outcome of the subsequent pregnancy after a first loss in women with the factor V Leiden or prothrombin 20210A mutations

BACKGROUND

The factor V Leiden (FVL) and prothrombin 20210A (PTm) mutations are associated with single late pregnancy loss and recurrent early pregnancy loss. The prognosis after an initial loss in women with thrombophilia is uncertain.

OBJECTIVE

To assess the pregnancy outcome of the second pregnancy after a first loss in women with and without either FVL or PTm mutations.

METHODS

We selected women with a first pregnancy loss out of two family cohorts of first degree relatives of probands with FVL or PTm mutations and a history of documented venous thromboembolism or premature atherosclerosis.

RESULTS

Ninety-three women had had a first pregnancy loss and became pregnant a second time. Their risk of loss of the subsequent pregnancy was higher than in 825 women with a successful first pregnancy [25 vs. 12%, relative risk (RR) 2.0, 95% CI 1.4-3.0]. The live birth rate of the second pregnancy after an early first loss ( 12 weeks), the live birth rates were 68% (95% CI 46-85) and 80% (95% CI 49-94) for carriers and non-carriers, respectively (RR 0.9, 95% CI 0.5-1.3).

CONCLUSIONS

Women with a first pregnancy loss have a 2-fold increased risk of loss of the subsequent pregnancy, regardless of their carrier status. More importantly, the outcome of the second pregnancy is rather favorable in absolute terms, even for those with thrombophilia and a late loss, which raises concern regarding the risks and presumed benefits of anticoagulant therapy in these women.

Natural Course of the Subsequent Pregnancy after a Single Loss in Women with and without the Factor V Leiden or Prothrombin 20210A Mutations

In previous case control studies factor V Leiden and the prothrombin 20210A mutation have been associated with pregnancy loss, in particular recurrent and late (>12 weeks of gestation) losses in women carriers1. The prognosis of a second pregnancy after an initial late pregnancy loss in women with inherited thrombophilia is uncertain; the live birth rate reported in different cohort studies varied from 11 to 98%2–4. This has led to a debate about whether low-molecular-weight heparin should be prescribed to women with thrombophilia and pregnancy loss, despite the absence of evidence about its effectiveness from placebo-controlled trials.

We determined the live birth rate of the 2nd pregnancy following a first loss in a large family study that included patients with documented venous thromboembolism or premature atherosclerosis and carriership of the factor V Leiden or prothrombin 20210A mutations and their 1st degree relatives. Ectopic or terminated pregnancies and pregnancies lost due to known chromosomal abnormalities were excluded, as well as pregnancies during which anticoagulants were used. A total of 993 women (498 carriers) who had had 2809 pregnancies (1420 in carriers) were analyzed. After an early pregnancy loss in the 1st pregnancy, the live birth rate of the 2nd pregnancy was 77% (95%CI 62–87) in carriers and 76% (95%CI 57–89) in non-carriers. After a late pregnancy loss in the 1st pregnancy, the live birth rate of the 2nd pregnancy was 68% (95%CI 46–85) in carriers and 80% (95%CI 49–94) in non-carriers (OR 0.9, 95%CI 0.5–1.3).

We conclude that the pregnancy outcome in women with either factor V Leiden or the prothrombin 20210A mutation is fairly similar to the outcome in women without these mutations. After a late pregnancy loss in the first pregnancy, the live birth rate in the second pregnancy tended to be somewhat lower for carriers than for non-carriers. The live birth rates for both carriers and non-carriers in this study was substantially higher than in some other cohorts, which may be due to the fact that the cohort was not selected based on obstetric indications. Given the observed favourable prognosis after a first pregnancy loss even in women with known thrombophilia and a late loss, low-molecular-weight heparin to improve pregnancy outcome should not be used before results from ongoing randomized placebo controlled trials have shown its effectiveness and safety.