Factor XI deficiency increases postpartum bleeding

Some women with factor XI deficiency, a genetic disorder, have an excessive risk of bleeding after childbirth, UK researchers report in the current issue of BJOG.

Factor XI deficiency is an autosomal recessive disorder, also called hemophilia C, in which patients who lack this clotting factor may or may not have a tendency to bleed. Patients generally don't have other symptoms, such as bruising or joint pain, but excessive bleeding can occur following dental work, trauma or surgery. Spontaneous bleeding is rare.

One group of patients with a high risk of having this blood-clotting factor deficiency is Ashkenazic Jews. Patients with this disorder can be identified by obtaining activated partial thromboplastin times.

Dr. Bethan Myers of Queen's Medical Center, Nottingham, and colleagues note that the treatment of pregnant women with factor XI deficiency poses a challenge because of the variability of bleeding and the risks associated with therapeutic replacement of this factor.

To investigate this further, the researchers reviewed the files of 105 pregnancies in 33 women with this disorder. Two hematologists examined the case notes and independently classified the women as "bleeders" or "non-bleeders."

Overall, there were 16 bleeders and 17 non-bleeders. Overall, pregnancy and delivery were uncomplicated in 71 percent of the women. Live births occurred in 76 percent of the non-bleeders and 65 percent of the bleeders.

There was no apparent between-group difference in the incidence of miscarriage, but bleeders had more than 7-times the risk of postpartum hemorrhage.

The researchers point out that a large, collaborative study is required to identify the factors that define the "bleeder" group among these patients.

Women with factor XI deficiency and a tendency to bleed require extra vigilance during delivery and prevention of caesarean sections, they conclude.

SOURCE: BJOG, May 2007.