I can only remember an occasional pregnant patient with hereditary angioedema for which the most important precaution is to make sure the anesthesiologists are aware, as well as reminding oneself of medications to avoid. I have never had a patient who also had preeclampsia, and this is the first time I have been contacted with such a query (Remember I receive many phone, and now E-mail queries yearly.) Thus I would venture , an association, if present is not strong.
On the other hand I am aware of anecdotal published reports of the association, and heridary angioedema is said to be associated with two disorders where the incidence of preeclampsia is raised, asthma, and lupus erythamtosis. Remember, if 3-4% of pregnant women develop preeclampsia, than one would guess 3-4% of women who have hereditary angioedema would. One would not write a case report for any woman with preeclampsia but would if by chance she also had the angioedem disorder. So much for case reports. Also, preeclampsia will repeat in ~20% of pregnancies, though here it appeared less severe the second time.
On theoretical grounds one might suspect a higher incidence given speculation of on the systemic inflammatory state and preeclampsia, as well as the fact that both asthma and lupus, by themselves, have increased incidences. Finally, while not for the querying patient but for those of use born before the age of molecular medicine, there is currently growing literature of the role of hypoxia genes in the placenta and the development of preeclampsia. But my answer still remains, no association that I am aware of.