Carriers of haemophilia
may have low levels of factor VIII or factor IX and as such
will have similar clinical problems to patients with mild haemophilia,
bleeding excessively following dental or surgical procedures
or following significant trauma. These patients may also have
particular problems with menorrhagia and bleeding at childbirth.
For these reasons,
haemophilia carriers with low levels of factor VIII or factor
IX should have access to appropriate obstetric and gynaecological
services.
These patients
may require a range of treatments for the diverse symptoms
that they can experience.
Factor VIII or
IX assays should be carried out on all carriers of haemophilia.
Those haemophilia carriers with low factor VIII or IX levels
should be formally registered with a Haemophilia Centre and
subject to regular review in the same manner as patients with
mild haemophilia.
A relatively small number of
carriers of haemophilia were infected with hepatitis or HIV.
These patients require access to the same range of services
as described for virally infected patients with haemophilia.
Identification of the
haemophilia gene and carrier
Genetic counselling should
be available before, during and after the process of haemophilia
genetic analysis.
A fully documented pedigree
study should be carried out for each family, allowing identification
of obligate carriers, possible carriers and non-carriers.
Intragenic polymorphism and linkage analysis
and/or direct gene analysis should be carried out to establish
carriership for female members of the family where there is
a patient with haemophilia.
Following a diagnosis
of carriership, there should be specialised genetic counselling
and education, so that carriers can understand the transmission
of haemophilia within their own family.
It is recommended that a network
of genetic testing centres be established that can provide nationwide
genetic analysis in haemophilia and related disorders.
All patients with haemophilia
should have mutation detection carried out.
The haemophilia carrier
and pregnancy
Pregnancy is a potentially serious
undertaking in haemophilia as both the mother and infant are
at increased risk of bleeding.
It is recommended that carriers
receive formal education about the transmission of haemophilia
within the family before starting a pregnancy, if at all possible.
There should be access to an expert fetal
medicine unit for discussion of ante natal diagnosis and pre-implantation
diagnosis.
It is essential that the obstetric
management of women with inherited bleeding disorders - and
known carriers of haemophilia - should be carried out in (or
in association with) Haemophilia Centres that have expertise
in this area.
A documented care plan for
the delivery of any male infant should be established.
There must at all stages of
the pregnancy be close collaboration between the obstetric team
and the Haemophilia Centre.
Postnatal confirmation
of the diagnosis should be carried out as soon as possible.
