QUESTION: My question is about the mitral heart valve, specifically mitral prolapse. Is it the same as mitral stenosis, which I have, along with atrial fibrillation? - S.C.F.

ANSWER: No, these are two quite different problems. I have answered several questions recently on the prolapse situation. Once more, briefly: The mitral valve regulates blood flow between the upper and lower left heart chambers. The prolapse is a floppiness of that valve, which, as I have noted, is quite common and harmless as long as it isn't producing troublesome symptoms.Mitral stenosis, on the other hand, is a narrowing of that valve, often due to rheumatic fever infection. If the narrowing is great, blood can back up into the upper chamber and eventually to the lungs. Mitral stenosis often causes erratic heart rhythm originating in the upper chamber, the atrial fibrillation to which you refer.

Often, the consequences of mitral stenosis can be controlled with medicines. Should the need arise, the mitral valve can be replaced. It's almost routine heart surgery in this day and age.

With this, perhaps we can shelve the mitral issue temporarily to give my readers a brief respite from the topic.

QUESTION: My daughter has terrible migraine headaches, which she is sure are connected with her period. She says she doesn't have them when she's pregnant or nursing a baby. She will soon be stopping nursing and is dreading a return of the migraines. She is convinced all this is due to too much estrogen. I cannot get her to go to a doctor. I am worried. She has a job and three children to care for. She also has vomiting with her migraines. - J.M.N.

ANSWER: Many women point to their periods as migraine triggers, and it is a well-known fact that hormonal changes associated with the menstrual cycle can be an influence. And yes, many other women report disappearance of migraines during pregnancy. So we do have reason to suspect a strong link between cyclic hormone changes and the headaches.

Your daughter's headaches seem to be on the severe side. If they are and if they are somewhat frequent, she could be a candidate for preventive drug treatment. I am thinking specifically of beta blocker drugs. Her doctor can be more specific. Also, naproxen is said to be especially helpful in menstrual-induced migraines. Has that been tried?

I don't see her resolving this problem alone. By not seeing a doctor, she may be missing an opportunity to end her nightmarish headache cycle. Booklet No. 15 (headaches) discusses various kinds and treatments. For a copy, readers can write Dr. Donohue/No. 15, P.O. Box 19660, Irvine, CA 92713, enclosing a long, stamped, self-addressed envelope and $1.