HHT and Pregnancy

Most women with HHT can experience normal pregnancy and delivery with the same amount of risk as women in the general population. Though HHT pregnancies are sometimes considered “high-risk," this is not usually the case. While women with more concerning HHT symptoms can benefit from a “high-risk” clinic approach, women who experience minimal symptoms may not need it. The key is to consult with an HHT expert to help make the best decisions for you and your baby.

Remember that HHT affects each person differently, and symptoms are known to change over a lifetime. How HHT affects your body should guide your pregnancy planning and care. For example, if you only experience telangiectasia in the nose and have no abnormal blood vessels in the organs, there's no reason to think your pregnancy or delivery is high-risk. On the other hand, if you have lung AVMs, then several steps and precautions need to be taken to minimize risk, and in some cases this may be considered a high-risk pregnancy.

Here's What You Need to Know

Myth #1:  Women with HHT are at risk of excessive bleeding from the uterus during or after delivery.

There is no evidence of this. In fact, women with HHT are no more likely to bleed excessively at delivery or after delivery than women in the general population.

Here’s why: People with HHT don’t have a clotting disorder. People with HHT bleed from parts of the body where they have abnormal blood vessels, not because of a regular injury, trauma or cut. The uterus is not a typical place for AVMs to occur in HHT, so there is no reason to expect women with HHT to bleed with delivery.

Myth #2: Women with HHT can’t have an epidural.

Rest easy  - this is not the case. Most women with HHT decide to have an epidural, or give themselves the option to have one available in the moment. There is no evidence of increased risk of complications. We'll break it down for you.

Why is there concern? Many anesthetists and other doctors are worried about the risks of epidural anesthesia in women with HHT, specifically about puncturing a spinal AVM when they insert the epidural needle into the women’s lower spine. Approximately 1 percent of HHT patients have AVMs in the spinal canal, but the majority of HHT spinal AVMs are higher on the spinal canal than where the epidural is inserted.

No case has ever been reported in medical literature of an epidural causing spinal bleeding in HHT. Complications of spinal AVMs are exceedingly rare in adults (most are discovered during childhood). In fact screening for spinal AVMs isn't routinely recommended in adults with HHT (unlike screening for lung and brain AVMs) given how rare they are in adults. In other words, if there is a risk, it's so low no one has been able to document a case or quantify the risk. However, there is no study “ruling out” risk of epidural in HHT - so we call it a “theoretical” risk.

If a pregnant woman with HHT wants the option of an epidural, she should get the option. Meet with the anesthetist prior to delivery and have a discussion about all the risks,“theoretical” or otherwise. Many anesthetists will agree to proceed if the woman understands the risks.

Myth #3: Women with HHT should have a cesarean section to avoid bleeding and other HHT complications with labor and delivery.

There is no evidence to support the C-Section as a routine approach for HHT patients. We've already discussed the myth of excessive bleeding in #1 so let us continue to other assumed complications.

The second concern is a brain AVM rupturing when pushing at delivery. There is no evidence to support this worry, or that cesarean section is a safer alternative to vaginal delivery in people with brain AVMs. However, this situation needs to be handled on an individual basis.  Screening for brain AVMs can be performed in early third trimester with an unenhanced MRI of the brain. If the MRI is negative, as it is for 90 percent of women with HHT, then there's no reason to be concerned.

If you do have a brain AVM, your case is considered high risk and needs to be discussed with a brain AVM expert and obstetrician. If a brain AVM is diagnosed, the usual recommendation is to treat within two or three months after delivery. As such, since treatment will be delayed anyway, some women opt to postpone the brain MRI until after delivery. This is not unreasonable, but may leave you and your physicians unnecessarily worrying about the possibility of brain AVMs and a false “high-risk” pregnancy.

There is also no evidence that a treated lung AVM is more likely to rupture and bleed during vaginal delivery. However, if you have an untreated lung AVM your pregnancy should be considered high risk. Screening and preventative treatment for lung AVMs should be done prior to pregnancy, when possible. If you are already pregnant, lung AVM treatment during Trimester 2 or 3 with embolization should be considered, but only at an expert HHT center. If you have lung AVMs that have been successfully treated (and recently reassessed), then lung AVMs are not a concern for pregnancy and delivery.

Summary

For most women with HHT, the main problem is nosebleeds, and though bothersome, this is not often a major concern during pregnancy. Some women with HHT have a more extensive issues, with AVMs in the brain or lungs, which may be more concerning. However, with the right screening, treatment and surveillance, most women with HHT can have normal pregnancy and delivery, with no more risk than women without HHT. Any patient with lung AVMs (treated or untreated) should follow pulmonary AVM precautions, including antibiotics before any procedures that can cause bacteria in the blood as well as using an air filter (bubble trap) any time there is an intravenous access.

References

  1. Faughnan, M.E., et al., International guidelines for the diagnosis and management of hereditary haem- orrhagic telangiectasia. J Med Genet. 48(2): p. 73-87.
  2. De Gussem, E.M., et al., Outcomes of Pregnancy in HHT(Abstract). Hematology Meeting Reports, 2009. 3(4): p. 10.
  3. Gershon, A.S., et al., Transcatheter embolotherapy of maternal pulmonary arteriovenous malformations during pregnancy. Chest, 2001. 119(2): p. 470-7.
  4. Shovlin, C.L., et al., Medical complications of pregnancy in hereditary haemorrhagic telangiectasia. QJM, 1995. 88(12): p. 879-87.
  5. Shovlin, C.L., et al., Estimates of maternal risks of pregnancy for women with hereditary haemorrhagic telangiectasia (Osler-Weber-Rendu syndrome): suggested approach for obstetric services. BJOG, 2008. 115(9): p. 1108-15.
  6. Wain, K., et al., Hereditary hemorrhagic telangiecta- sia and risks for adverse pregnancy outcomes. Am J Med Genet A, 2012.
  7. http://www.nichd.nih.gov/health/topics/high_risk_ pregnancy.cfm