Pregnancy and delivery
It is strongly advised to undergo screening before becoming pregnant.
It is important that women of child-bearing age who may wish to have a baby and who belong to a family with HHT are tested and treated for vascular abnormalities before pregnancy. A check-up after labour is necessary because small residual pulmonary vascular malformations may grow larger. Embolization of significant vascular malformations is possible during pregnancy despite radiation exposure.
Pregnancy usually progresses normally and miscarriages are no more common than in the normal population. Natural childbirth is possible, preferably in an outpatient department or hospital, because pushing may provoke nosebleeds. Epidural anaesthesia, in general, is not a problem.
Pregnancy and a CAVM
Pregnant patients with a cerebral vascular lesion (CAVM) are possibly at some risk of haemorrhage. The magnitude of the risk is not known exactly and will depend on the angio-architecture of the lesion.
The Dutch view on this problem is that women, who want to become pregnant, have to be screened for CAVMs before, especially when HHT-1 runs in the family.
If the woman is already pregnant with an untreated CAVM, that has not bled, a normal vaginal delivery is indicated with epidural anaesthesia. The second stage of labour (pushing) should not last too long and may be shortened with vacuum extraction. When the CAVM has bled, the neurologist decides about the mode of delivery.
If the woman is already pregnant and it is not known, whether a CAVM is present, a vaginal delivery with epidural anaesthesia and shortened second stage of labour is advised, when it concerns HHT-1 or when the type of HHT is not known. In case of HHT-2 a normal vaginal delivery is recommended.
When the baby is born
The baby should be treated just as any other baby, but it will have a chance of 50% to have HHT. It is prudent to measure the oxygen saturation (oximetry) because a low level may point to a pulmonary vascular abnormalities. Of course, a more extensive examination will be necessary, if the baby has any symptoms.
The parents should consider carefully whether they want the baby’s DNA to be tested. It is, of course, a great relief when the DNA test shows that the baby is not affected, but the chance of inheriting the disease is 50% for each child. Symptoms will usually only appear after several years and all this time the parents will have to contend with the knowledge that their apparently healthy child has HHT. Another argument against DNA testing is that the child, when he/she is older, may not want to know whether he/she has HHT.