Drug's effects on embryonic blood-vessel growth may be the source of malformed limbs. Thalidomide's effect on growing blood vessels may have caused birth defects in thousands of children.National Cancer Institute More than 50 years after the drug thalidomide hit the market as a remedy for nausea in pregnant women, researchers may finally have pinned down how it causes severe birth defects. Their results show that the drug's ability to block the development of new blood vessels may be behind the deformed limbs of children born to women who took thalidomide early in pregnancy. The finding could contribute to the development...