In their study, published in the journal Reproductive BioMedicine Online, the team’s chances of producing a successful live birth after in-vitro fertilization (IVF) were increased by 56 percent using the new technique compared to the standard method of selecting embryos that look best through a microscope.

“In the 35 years I have been in this field, this is probably the most exciting and significant development that can be of value to all patients seeking IVF,” said Simon Fishel, a leading fertility doctor and director at the IVF clinic operator CARE Fertility where the technique is being developed.

Independent scientists not involved in the work welcomed it as a significant advance but said full randomized controlled trials – the gold standard in medicine – should be conducted before it is adopted as mainstream practice.

“This paper is interesting because we really do need to make advances in selecting the best embryos created during IVF,” said Allan Pacey of Sheffield University, chair of the British Fertility Society.

“The idea of monitoring embryo development more closely is being used increasingly in clinics around the world and so it is good to see the science involved submitted to peer review and publication,” he added. “All too often, developments in IVF are trumpeted as advances when they remain unproven.”

Experts say that today, as many as 1 to 2 percent of babies in the Western world are conceived through IVF. The standard methods of selecting embryos are based largely on what they look like through a microscope, and many IVF cycles fail because the embryo chosen and transferred to the womb fails to develop.

“One important message is women who need to use fertility drugs to get pregnant should not worry about using these fertility drugs,” said Dr. Albert Asante, lead author of the study and a clinical fellow in the division of reproductive endocrinology at the Mayo Clinic in Rochester, Minnesota….

….Infertility, defined as not getting pregnant after a year of trying, is experienced by about 15 percent of couples.

Asante’s team looked specifically at whether women in the study who reported being infertile- whether or not they had taken fertility drugs – had a greater chance of developing ovarian cancer, and found no added risk.

Asante said one explanation for the result is that most of the women in his study had infertility issues, but eventually became pregnant. He would still expect to see a higher risk of ovarian cancer if he had included more women who never ended up having a baby.

Asante left open the possibility that long term use of fertility drugs – more than one year – could impact the chance of developing ovarian cancer, and to be safe these women might benefit from additional monitoring for tumors.

He said that because ovarian cancer is rare and develops later in life, there is a need for longer studies to thoroughly assess the effect of fertility drugs.

According to the National Cancer Institute, close to 13 out of every 100,000 women develop ovarian cancer, most commonly in their 60s. Family history of the disease or certain gene mutations raise a woman’s risk considerably.

In 2010, Edwards was awarded the Nobel prize in medicine or physiology for the development of IVF.

Swedish researchers compared 23,498 women who had given birth after I.V.F. from 1990 to 2008 with 116,960 women of the same age and general health who had natural pregnancies. The results appeared online last week in the journal BMJ.

Women with I.V.F. pregnancies had more than four times the risk of venous thrombosis during the first trimester, compared with those with natural pregnancies, and almost seven times the risk of pulmonary embolism. The difference narrowed, but persisted, as the pregnancies progressed.

The I.V.F. procedure induces multiple egg production with high doses of hormones, and the authors suggest that this may be the cause.

“Women who are going to have I.V.F. should know these findings,” said the lead author, Dr. Peter Henriksson, a professor of internal medicine at the Karolinska Institute. “And if they have had blood clots themselves, or have relatives with thrombosis, they should be treated with blood thinners.”

“Agerbo was able to make use of Denmark’s detailed and complete system of medical records. They looked at data on 21,276 childless couples who registered for in vitro fertilization (IVF) treatment between 1994 and 2005.  The first three cycles of IVF were free until 2010 in Denmark’s national health system.

During this time, 15,210 children were born and 1,564 were adopted, Agerbo reports in the Journal of Epidemiology and Community Health. And over the same time, 96 of the women and 200 of the men died. Four times as many women who did not have children died as women who had or adopted a child, Agerbo’s team found. Death rates were twice as high among the men who did not have children.

“Mindful that association is not causation, our results suggest that the mortality rates are higher in the childless,” the researchers wrote.

What could the reason be?

“Parents are less likely to die from accidents, circulatory diseases, cancer, and external causes — thus I suggest a behavioral difference,” Agerbo says. “Our study was not large enough to say whether suicide was less common among parents, but the rate of accidents is higher among non-parents — perhaps I am more prone to buy a big motorcycle or a fast car than family-friendly slow van.”

Alice Domar, a psychologist at Beth Israel Deaconess Medical Center in Boston and director of mind-body services at Boston IVF, agrees. “When you have kids, it completely changes the way you live your life. I suspect that is what going on,” she said.”