Q. Some time ago I read that taking blood pressure medication could lessen your sex drive. The reason I mention this now is that my husband, who has been taking blood pressure medicine for approximately three years, seems to have lost his ability, but not his desire, to have sex. Is this something we should check out, with the idea of perhaps changing his medicine?

A. I think it's a good idea for your husband to mention this problem to his physician, and I'm a little surprised that he hasn't done so by now.

Blood pressure medicines can affect sexual function in several ways, including their effects on nerves, blood vessels, hormones and the brain. Different medicines can affect different aspects of sexual function to varying degrees, but it's worth telling your doctor about any changes in sexual function that develop after starting a new medicine.

Blood pressure medicines can cause impotence, loss of sexual interest and problems with ejaculation or vaginal lubrication. Your husband's doctor may want to switch him to a different medicine, or temporarily take your husband off his medication, to see if there's a difference in his sexual function. If so, his doctor will try to find another medicine that will work without causing this kind of problem.

I should point out, however, that your husband's high blood pressure itself, rather than its treatment, may be the cause of his difficulty. People with untreated high blood pressure have a higher rate of impotence than people with normal blood pressure. So medication might not be the cause of your husband's problem at all.

I said I was surprised that your husband hadn't discussed his problem with his doctor, but actually I'm not. Many people are embarrassed, or don't consider sexual function a medical matter and don't realize that certain diseases may cause symptoms in your sexual drive or performance. This may be the case, for example, with diabetes, thyroid problems, hardening of the arteries, spinal cord disorders, and depression and anxiety. It's very possible that another problem, physical or emotional, is responsible for your husband's difficulty.

Because many causes of sexual function problems respond to treatment, especially if it means doing something as simple as switching to another blood pressure medicine, I'd recommend that your husband see his doctor for evaluation.

Q. During my seventh month of pregnancy, I found out I had gestational diabetes. My son is now 4 months old, and is somewhat behind in development. He doesn't hold his head up normally or follow objects with his eyes. Can gestational diabetes cause these problems?

A. I don't think gestational diabetes is responsible for your son's problems, but I certainly recommend that he be thoroughly checked right away.

Gestational diabetes is diabetes that develops during pregnancy. It's linked with a slightly increased risk of stillbirths, pregnancy-induced high blood pressure, large babies (which may make for difficult births and related complications) and low blood sugar in newborns.

Because good treatment exists for gestational diabetes, starting with diet control of blood sugar levels, the American College of Obstetricians and Gynecologists recommends that all women be tested for gestational diabetes between the 24th and 28th week of pregnancy.

The situation is completely different for women with diabetes before they become pregnant. This is a more serious condition with greater threats to both mother and fetus. For these women, pregnancy is a 12-month process.

To reduce their risk of birth defects, it's important for women with diabetes to keep their blood sugar levels as normal as possible, especially during the early stages of fetal development (the first 10 weeks of pregnancy). I recommend that they get their prenatal care from a medical center specializing in care of women with diabetes, starting before they become pregnant.

Q. Is it safe to feed an infant breast milk that has been frozen in disposable plastic bottle liners, the kind that come in the Playtex Baby Nurser Kit? I was told that disposable bottle liners could become toxic when stored in the freezer. How soon after thawing should breast milk be used?

A. With more women returning to work shortly after having a baby, many new mothers are pumping their breasts and storing their milk so that their infants may receive the benefits of breast milk even when they can't be there to feed them. Mothers of sick or premature infants who must remain in the hospital are also storing their milk for later feeding.

Until recently, nurse counselors at the Community Human Milk Bank had no objections to using plastic bottle liners for this purpose. However, two potential problems are connected with their use -- the plastic can tear, and there is some suggestion that milk enzymes may adhere to the plastic lining. It's unclear whether the loss of a small amount of milk enzymes is important or not. The LaLeche league, an organization that promotes nursing, approves of using plastic liners -- double bagged to prevent tearing.

In any event, freezing milk in plastic bottle liners won't make it toxic.

Instead of plastic liners, nurses at the Milk Bank recommend that you use ordinary glass baby bottles or jars to freeze milk in. The bottles don't break, as long as they're not overfilled. Thawed milk should be used within 30 minutes or be refrigerated, where it will keep for 24 hours.

For more information about storing breast milk, write to the Community Human Milk Bank, Georgetown University Hospital, 3800 Reservoir Rd. NW, Washington, D.C., 20007, or call one of the nurse counselors at 625-MILK.