"The U.S. Food and Drug Administration for the first time ever has greenlighted a birth control httpsabcnews.go.comalertsBirthControl app httpsabcnews.go.comalertsApple to be marketed as a method of contraception.  The app Natural Cycles calculates when a woman is most likely to be fertile using their daily body temperature data and their menstrual cycle information.  The app then tells users what days they are more likely to be fertile and should abstain from sex or use protection if they do not wish to get pregnant. Consumers are increasingly using digital health technologies to inform their everyday health decisions and this new app can provide an effective method of contraception if its used carefully and correctly Dr. Terri Cornelison the assistant director for the health of women in the FDAs Center for Devices and Radiological Health said in a statement.  But women should know that no form of contraception works perfectly so an unplanned pregnancy could still result from correct usage of this device she added.  The app had a perfect use failure rate of . percent in clinical studies that involved more than  women or a typical use failure rate of . percent according to the FDA. The typical use failure rate took into account women who sometimes did not use the app correctly or may have had unprotected sex on a day when the app flagged that they were fertile. Natural Cycles has however courted controversy in Europe as some women have reported unwanted pregnancies while using the app as their main form of birth control.  Swedens public broadcasting company SVT reported that  out of  women who received an abortion at a Stockholm hospital from September  to the end of December  were using the app and still had an unwanted pregnancy.  ABC News chief medical correspondent Dr. Jennifer Ashton emphasized that no method of contraception is perfect except abstinence so its not completely surprising that women have still gotten pregnant while using it.  Ashton added that apps can be useful in that they enourage women to be aware of their bodies monthly changes. If a woman does decide to use an app for birth control however she needs to have a plan for what she would do if she does have an unplanned pregnancy.  Most contraception pills have a typical use failure rate of approximately  percent according to Ashton which is actually higher than the rate of the app the FDAs data showed.  Still Asthon says that women should ask their doctors about risks benefits and alternatives for any contraceptive method they are using."