HHT and Pregnancy
Myths of High Risk Pregnancy
High-risk pregnancy occurs when some condition puts the mother and/or fetus at risk of
complications during or after pregnancy and birth. These women can benefit from
additional monitoring and specialized care.
Myth #1: Women with HHT have a higher risk of excessive bleeding from the uterus
during or after delivery.
There is no evidence to support this myth. Since HHT is not a clotting disorder, people
affected by the disease are not more likely to bleed from injury or trauma. Bleeding
occurs at sites in the body where abnormal blood vessels (AVMs and telangiectasias) are
present. The uterus is not a typical place for either, however, if concerned, ensure that
the treating physician is aware of the HHT diagnosis
Myth #2: Women with HHT can’t have an epidural.
Most women with HHT have the option of an epidural and there is no evidence for
increased risk of complication. The concern with epidurals is that an epidural needle
could puncture a spinal AVM, which occur in approximately 1% of HHT patients. The
vast majority of spinal AVMs are found much higher in the spine than where an epidural
would be given. Spinal AVMs are so rare in adults that regular screening for them is not
even recommended.
Myth #3: Women with HHT should have a cesarean section to avoid bleeding or
complications during delivery.
The concern with bleeding during delivery is addressed in Myth #1. The second concern
is that brain AVMs may rupture during the stress of delivery. There is no evidence to
indicate that a cesarean section is less likely to cause this than vaginal delivery, and the
delivery method should be handled on a case-by-case basis. The final concern is that
“pushing” at delivery could rupture lung AVMs. Lung AVMs are only more likely to
rupture at delivery if left untreated.
Relevant Statistics
20% miscarriage rate (similar to the rest of the population)
78% of miscarriages in first trimester
93% of pregnancies had no serious complications
31% increased frequency of nosebleeds
14% increased telangiectasia
Potential Complications:
Though not common, these HHT-associated complications have been identified in past
studies.
Pulmonary AVM – complications in 11 (out of 185), including coughing up blood, chest
bleeding, transient stroke, myocardial infarction – none were screened for PAVMs prior
to pregnancy or aware that they had HHT
Cerebral vascular malformation – stroke due to bleeding from cerebral vascular
malformation (1), had history of stroke, risk of developing a bleed is higher once it has
bled before
Liver vascular malformation – heart failure (1), no preventive precautions, but very rare
C-section – 30% of deliveries by c-section, similar to the general population
Epidural – 92 (50%) had epidural without screening for spinal vascular malformations
with no complications, no report of a woman with HHT developing complications from
an epidural in current literature
Newborn health – average weight and length of pregnancy was similar to the general
population unless the mother presented with hemothorax (chest bleeding due to
pulmonary AVM)
Conclusion: Complications occurred in women who had not been screened or treated for
AVMs prior to pregnancy.
Recommendations:
1. Get screened for pulmonary AVMs if you have, or suspect you may have, HHT
and have any significant PAVMs treated by embolization prior to pregnancy.
2. Get screened for cerebral vascular malformations prior to pregnancy –
management of any existing cerebral vascular malformations should be discussed
with an expert team.
3. Consult with an anesthetist prior to delivery regarding the use of an epidural so
that a decision can be made on a case-by-case basis.