Q: I have rhesus-negative blood and my husband has B positive. We do not have any children now. I heard from my friends that if we have children our babies may have problems because of our blood incompatibility. My doctor explained it but I don't really understand what the problem is. Can you please help? Dr Rose writes: If you have rhesus-negative blood and you have a child with a man who is rhesus-positive, you run the risk of having a child who is rhesus-positive. If any of the baby's blood leaks into your circulation, this will be recognised by your body as ''foreign''. Your red blood cells will automatically produce antibodies to destroy the foreign cells in the foetus. With a first pregnancy, problems usually do not arise because the maternal rhesus antibodies have not formed sufficiently to harm the baby. However, with subsequent pregnancies with a rhesus-positive baby there is a risk that rhesus antibodies will increase in amount and cross the placenta and attack the foetal blood cells. When this happens, the baby may experience severe anaemia and jaundice and may require a blood transfusion. To prevent the formation of antibodies your physician will give you an injection of rhesus immune globulin, usually within 48 to 72 hours after delivery. These antibodies will destroy any red blood cells that have entered your bloodstream from the foetus. Fortunately, with the development of rhesus immune globulin, haemolytic disease has become extremely rare. The rhesus immune globulin is also given to rhesus negative women in any situation where there is the possibility of foetal blood cells passing into the maternal circulation; for example, within 48 to 72 hours of a miscarriage, abortion or amniocentesis. If you decide to have children, your doctor will monitor you during the pregnancy. Rhesus-negative women are tested at the first prenatal visit and at 32 and 38 weeks' gestation. The tests are more frequent if it is a second or subsequent pregnancy. Amniocentesis may be performed to determine if the baby's blood cells are being destroyed. If this is the case, and it is too early to induce labour, your doctor may perform a series of foetal blood transfusions. Rhesus incompatibility is far more common in Caucasians than Asians. Q: EVER since my daughter suffered from gastro-enteritis, about two years ago, she's been plagued with constipation that is only relieved by using suppositories. I'm concerned that the long-term use of suppositories is harmful to her, but she said there is no alternative. Are there other ways to facilitate a bowel movement? Dr Rose writes: While the occasional use of a rectal suppository to facilitate a bowel movement is medically acceptable, long-term use can be harmful. Your daughter can facilitate a bowel movement by increasing the amount of fibre in her diet. Bran, green leafy vegetables, fresh fruit and whole grain breads are all foods that are high in fibre and provide the bulk that the colon muscles need to stimulate the movement of faecal matter. Drinking lots of fluids also helps prevent constipation. She should also try to establish a regular routine for using the toilet. If the constipation continues despite these measures, she should consult her physician for further investigation. Q: WHILE travelling in China I had a severe episode of pain which a local doctor diagnosed as a kidney stone. Luckily it flushed out by itself when I was urinating. I heard that there is a new procedure using ultrasound or shock waves to dissolve the kidney stones. Is that correct? Dr Rose writes: Kidney stones are formed when there is an extremely high concentration of calcium oxylate, or other minerals, in the body. After they are formed in the kidneys, they may become trapped in the ureter, or in some areas of the bladder where they can cause acute pain, spasms, and nausea and vomiting in the afflicted individual. In some cases, they may cause obstruction and infection leading to more severe problems. Lithotripsy, a new procedure where ultrasonic or shock waves are used to break up kidney stones so that they can be easily excreted in urine, offers new hope to sufferers. The physician performs the procedure under general anaesthetic or by epidural (anaesthetising the lower part of the body only). A small cut is made in the patient's flank and a tube is inserted into the kidney. A special probe is then passed through the tube and ultrasound waves are directed at the kidney stones to shatter them. The fragmented stones are then removed through the tube. The patient must drink copious amounts of water to help clear any remaining stone fragments from the body. Side-effects of this procedure are minimal. The patient may have blood in the urine and experience some abdominal bruising. Most individuals return to work after a week. Lithotripsy has eliminated the need for most kidney stone surgery. Success varies according to the size and location of the stones. Consult your physician for further details. The procedure also holds promise for the treatment of gallstones. Dr Rose Ong is a certified family physician licensed in the United States. She welcomes enquiries but cannot answer them individually. Specific questions should be addressed to your own physician. Additional enquiries: Peak Corporate Health Management, 525-6600, fax 525-8100.