(NaturalNews) Since the approval of human papillomavirus (HPV) vaccine Gardasil in June 2006, 28 cases have been reported of pregnant women miscarrying after receiving the vaccine. Saying that this miscarriage rate is no different than that of the general population, the FDA has said that it will not call for further investigations into the drug's safety.The miscarriage reports come from the Vaccine Adverse Event Reporting System (VAERS), which contains raw data about any event that occurs after taking a medication that might be related to use of the drug.Gardasil, produced by Merck, protects against two strains of HPV that have been identified as responsible for 70 percent of cervical cancer cases, plus two strains that cause 90 percent of genital warts. A total of 3,461 negative reactions after taking Gardasil were reported to the database, including eight deaths.Of the 28 reported miscarriages, several were listed as cause unknown, leading a federal investigator to say that one of these, at least, "may have been caused by Gardasil because the patient received the injection within 30 days of the pregnancy."In clinical trials conducted by Merck, the number of women who had miscarriages after being given the vaccine was not significantly different than the number among those given a placebo. In addition, the company points to studies on rats in which 300 times the human dose failed to produce reproductive effects. But the company's literature on the drug says, "It is not known whether Gardasil should be given to pregnant women."Three U.S. states have passed laws mandating HPV vaccines for school-age girls, and 38 other states have considered similar laws. The American College of Pediatrics and "New England Journal of Medicine," however, have opposed mandatory vaccination with Gardasil.