单选题：Pregnant women warned about ACE inhibitor Some of the most c

Pregnant women warned about ACE inhibitor
Some of the most commonly used medicines for high blood pressure are drugs called ACE inhibitors .Doctors have given these drugs to patients for twenty-five years．A government study in the United States found that the use almost doubled betweenl995 and 2000．
Doctors have known for years that women should not take ACE inhibitors during the last six months of pregnancy．The medicine can injure the baby．ACE inhibitors，though，have been considered safe when taken during the first three months．But a new study has found that women who take these drugs early in their pregnancy still increase the risk of birth disorders．The study shows that compared to others，their babies were almost three times as likely to be born with major problems．
These included problems with the formation of the brain and nervous system and holes in the heart．the researchers say they found no increased risk in women who took other blood pressure medicines during the first three months．Researchers at Vanderbilt University in Tennessee and Boston University did the study．The New England Journal of Medicine published the results．The researchers studied the records of almost thirty thousand births between 1985 and 2000．Two hundred nine babies were born to women who took ACE inhibitors during the first three months of their pregnancies．Eighteen of the babies，or almost nine percent，had major disorders．
ACE inhibitors are often given to patients with diabetes．But diabetes during pregnancy can result in birth defects．So the study did not include any women known to be diabetic．ACE inhibitors sup．press a protein called angiotensin—converting enzyme，or ACE．This enzyme produces a chemical in the body that makes blood passages narrow．The drugs increase the flow of blood so pressure is reduced．
New drugs are tested on pregnant animals to see if they might cause birth defects in humans．But experts say these tests are not always dependable．The United States Food and Drug Administration helped pay for the study．The F．D．A．says women who might become pregnant should talk with their doctor about other ways to treat blood pressure．
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