Special Issues for People with PNH | Aplastic Anemia and MDS International Foundation (AAMDSIF) Return to top.

Special Issues for People with PNH

Introductory image: Health Professional and Patient Looking at a Tablet in a Hospital Setting

Because you have PNH, everyday events can be more risky for you than for healthy people. Here are some examples.

Airplane Travel and High Altitudes

The farther you get from earth, the less oxygen there is. If you have anemia, flying in an airplane or going up high may cause a shortage of oxygen. It may also cause chest pain. Before you do either of these things, it's a good idea to:

  • Get a red blood cell count
  • Get treatment for your anemia (blood transfusions or growth factors)

If you do fly, remember to:

  • Drink plenty of water
  • Get up and walk around every hour or two if it is safe to do so


Patients with PNH should receive vaccinations against certain types of bacteria to prevent infection. Ask your doctor which ones are right for you.

Seasonal flu vaccines protect against the three influenza viruses (trivalent) that research indicates will be most common during the upcoming season. Consult with your hematologist about whether you should get a flu shot. Your doctor will help you weigh the risks and benefits of getting a flu shot. Don’t forget to ask whether your family members and others in close contact with you should get a flu vaccine. This may reduce your chance of getting the flu. [link to eInsider piece http://www.aamds.org/facts-for-life/flu-shots]

  • For PNH patients, there are also a few case reports of flares of hemolysis (when red blood cells are destroyed) after receiving a flu shot. Although case reports are not the same as randomized clinical trials, one case of hemolysis was severe enough to put the patient in the hospital. Thus some experts recommend that PNH patients not get a flu shot, but again your case may be different. However, PNH patients who are receiving eculizumab may be less likely to have hemolysis after receiving a flu shot.


Pregnancy is possible with PNH, but it's not a good idea. It carries serious risks for both mother and child.

A woman with PNH faces a number of risks during pregnancy:

  • Her blood may have fewer healthy cells.
  • Her bone marrow may make fewer healthy cells.
  • She is more likely to get blood clots. Most doctors place pregnant women with PNH on blood thinners, to prevent clots. But warfarin (Coumadin®) cannot be used during the first trimester, since it may affect the way the fetus develops. 
  • She is more likely to get preeclampsia. That's a dangerous condition that causes very high blood pressure and can put both mother and baby at risk. 
  • She may need red blood cell transfusions more often.

A baby whose mother has PNH has a greater risk of:

  • Being born too soon
  • Dying in the womb 
  • Having a low birth weight
  • Having delayed growth and development

Still, about 1 out of 3 babies whose mothers have PNH do not have any of these problems.

If you do get pregnant, look for a PNH specialist and an OB (obstetrician) who specializes in high-risk births.


Surgery can also be risky for people with PNH because surgery:

  • Makes the complement system more active, which can cause hemolysis
  • Increases the risk of getting blood clots
  • Can cause serious bleeding in people with a low platelet count; platelet transfusions may be needed before surgery.

If you do have surgery, it's a good idea to:

  • Make sure your PNH specialist talks with your surgeon
  • Take the blood thinner Heparin (Calciparine® or Liquaemin®) as soon as possible after surgery, if you don't have a low platelet count and if your doctor says you should.