Complications are uncommon for women undergoing IVF procedures: A new 12-year U.S. study shows the most frequent involve drugs used to stimulate ovaries, but it suggests problems are rarely fatal. Over-stimulated ovaries occurred in 154 out of every 10,000 pregnancy attempts; rates of other complications were less than 10 per 10,000 attempts.  There were 58 deaths reported during the 2000-11 study. The study lacks information on their causes, and with more than 1 million pregnancy attempts involved, the results are reassuring, said Dr. Jennifer Kawwass, an Emory University assistant professor and the lead author. The study is the first large-scale effort to quantify risks for U.S. patients undergoing these treatments, Kawwass said. Results were published in Tuesday's Journal of the American Medical Association. Dr. Richard Paulson, vice president of the American Society for Reproductive Medicine, said many complications and deaths could have been from underlying conditions causing infertility, rather than the treatments. Doctors in recent years have limited the number of embryos transferred, to reduce chances for unsafe multiple births. Paulson, director of the University of Southern California's fertility program, said the move could lead to a decline in some complications including those related to over-stimulated ovaries. Dr. Jamie Grifo, director of New York University's fertility center, noted that about 2 percent of U.S. babies are born from IVF, and said the study confirms that risks facing women undergoing the procedure are small