Ectopic Pregnancy More Likely Among Women Who Use Frozen -- Not Fresh -- Embryos for IVF, Study Says
October 16, 2003
Women undergoing in vitro fertilization treatments who use frozen embryos have a higher risk of ectopic pregnancy than women who use fresh embryos, according to a study presented at the annual conference of the American Society for Reproductive Medicine in San Antonio, Texas, BBC News reports. Dr. David Keefe and colleagues from Brown University and Women & Infants' Hospital in Providence, R.I., studied the medical records of women who underwent IVF treatments at Women & Infants' Hospital between January 1998 and March 2002. The researchers discovered that six in 19, or 31.6%, of the women who had IVF treatment using frozen embryos had ectopic pregnancies, compared with nine in 490, or 1.8%, of women who underwent IVF with fresh embryos. An ectopic pregnancy -- in which the embryo implants outside the uterus in the fallopian tubes, ovary, abdomen or cervix -- can lead to internal bleeding and can be life-threatening. Approximately one in 100 pregnant women is affected by the condition, according to BBC News (BBC News, 10/15).
"We found that nearly one-third of frozen embryo transfer pregnancies were ectopic, 17 times more frequent than seen with fresh IVF cycles," Keefe said, adding, "Now the burden is on us and others to figure out why." Keefe said that his team was "surprised" by the study's results; however, he pointed out that the number of women involved in the study is small, according to London's Daily Telegraph. A long-term study of IVF technique safety is expected to be announced by the British Medical Research Council and Human Fertilisation and Embryology Authority, according to the Daily Telegraph. HFEA spokesperson Alison Cook said, "We know that there is a slightly increased risk, but this study raises serious concerns and needs to be investigated" (Derbyshire, Daily Telegraph, 10/15). Richard Kennedy of the British Fertility Society said that there is "no reason" to believe IVF treatments using frozen embryos carry increased ectopic pregnancy risk, according to BBC News. Kennedy said, "We have been using frozen embryos for over 15 years and have carried out thousands of frozen embryo cycles," adding, "There is no anatomical or biological reason why using a frozen embryo would increase the risks of an ectopic pregnancy." Kennedy said, "I would be very cautious about drawing any conclusions from these findings, not least because of the small numbers involved" (BBC News, 10/15).
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