At fertility clinics across Britain, patients undergo more than 60,000 in-vitro fertilization (IVF) cycles each year. Only about 24% of them result in a live birth. The IVF success rate in the US is about the same. A fertility specialist in Spain is developing a new technique that may increase the success rate for women everywhere.

Professor Juan Garcia-Velasco, of the IVI fertility clinic in Madrid, thinks one problem with the low success rate is bad timing. Many cycles fail because the embryo never implants into the uterine wall. He says the uterine lining (endometrium) will allow an embryo to implant successfully only on two to four days per cycle. His new technique helps identify exactly when the timing is perfect for implantation.

Currently, fertility clinics use ultrasound to assess the visual appearance of the endometrium; this visual check gives a general indication of health. It does not reveal the genetic activity that occurs when the endometrium is receptive to implantation.

In his pilot study, Garcia-Velasco took biopsies of the endometrium of 85 women undergoing IVF. The women had had an average of five IVF cycles that failed when the embryo did not implant. After the uterine tissue was analyzed for receptivity by Garcia-Velasco’s research team and embryos transferred according to the genetic activity exhibited in the tissue samples, the implantation rate soared to 33%.

In a second round of study currently underway, Garcia-Velasco is working with 2,500 patients seeking treatment at fertility clinics in ten nations, including Britain.

“The weakest link in IVF is implantation failure. I believe this is a breakthrough,” said Geeta Nargund, medical director of the London clinic of Create Fertility. Her clinic is taking part in the Garcia-Velasco study. “if you miss that window, no matter how beautiful the embryo, it’s not going to implant,” she said.

Professor Nick Macklon, of the University of Southampton’s obstetrics and gynecology department, estimates problems with the womb lining explains approximately two-thirds of the reason why recurrent implantation failure is experienced. The remaining one-third he attributes to embryo abnormalities. He feels the tests Garcia-Velasco is working on “could significantly improve success rates.”

Macklon also said, “We know embryos can be perfect and still they don’t implant,” a situation that “frustrates doctors and patients alike.”

As the Garcia-Velasco assessment test is perfected, the researchers hope to transition away from invasive uterine biopsies and use samples of endometrial fluid instead. At this time, the biopsies are done at least a month before embryo transfer because the biopsy itself disturbs the endometrium, a situation that discourages implantation.


  1. Devlin, Hannah. "IVF test improves chances of implantation by pinpointing fertility window." The Guardian. Guardian News and Media Limited, 9 Mar. 2015. Web. 17 Mar. 2015.
  2. "Fertility Clinic Success Rates." CDC / Assisted Reproductive Technology (ART) Report. Centers for Disease Control and Prevention, 13 Aug. 2013. Web. 17 Mar. 2015.