In Canada, about 71 per cent of embryo transfers fail, making it hard to know which ones to implant.Chris Maynard/The New York Times
Advances in fertility medicine are fast-paced. New ones are hardly out of the lab before they're offered as "treatments" – one fertility doctor's "experimental" is another's "state-of-the-art."
With so many points in the process for babymaking to go wrong, and would-be parents willing to fork over tens of thousands of dollars for success, it's no surprise the field is constantly changing. Here's a sampling of some of the up-and-coming fertility offerings.
Energy boost
Older women's eggs often don't develop properly after they're fertilized. As a possible solution, researchers are looking at mitochondria, the cell's energy source. A poor supply seems to hinder embryo development; adding extra mitochondria from young donor eggs seemed to help the few times it was tried.
Researcher Dr. Jonathan Tilly, then at Massachusetts General Hospital in Boston, discovered that human ovaries harbour what may be stem cells. These early "precursor" cells can be mined for extra, and possibly less damaged, mitochondria – even from older women to use themselves. Harvesting those mitochondria and injecting them into a woman's own mature egg as she goes through in vitro fertilization is the idea behind a new treatment called "Augment."
Doctors do a small tissue biopsy of the outer layer of the ovary, which contains the precursor cells. The mitochondria are then removed and injected back into the egg along with the sperm during in vitro fertilization.
Last year, the company OvaScience enrolled 150 women to try it out – and some of the field testing took place in Canada, at the Toronto Centre for Advanced Reproductive Technology. Dr. Robert Casper, TCART's medical director, says he is "very encouraged." A few patients who had never been pregnant before are now expecting. Although no data have been released, the treatment will be offered commercially at four centres this year, including TCART. But it will add a whopping $25,000 or so to the already steep costs of IVF.
Waking up the ovary
About one woman in every 100 has "premature ovarian failure" (POF) – she stops menstruating before age 40. About half of those diagnosed actually do still have some eggs in their ovaries, which for some reason don't fully develop.
Dr. Aaron Hsueh at Stanford University in California and his Japanese collaborators suspected the problem was caused by a signalling pathway known as Hippo. They knew from lab research that the signal could be disrupted by damaging the tissue. So they decided to try that in POF patients.
The team surgically removed the ovaries of 27 women and found that 13 of them had partially developed eggs. The researchers broke strips of ovarian tissue into tiny cubes then bathed them for two days in special lab compounds. Between 40 and 80 of the treated cubes were then transplanted back into the women's bodies (the rest of the chopped-up ovary was kept frozen) and watched for egg growth. Within half a year, eggs began to grow and the doctors helped them along with hormones. In five cases, fully matured eggs were successfully surgically removed for IVF. Two babies have so far been born and a handful of other patients have cryopreserved what appear to be healthy embryos. Dr. Paul Chang, a fertility physician at TCART, says that although this research is "very early," it is also "very promising." IVA, or in vitro activation, as it's called, is currently only available as a treatment in Japan.
Picking winners
Even once you have harvested good eggs and managed to fertilize them, not every embryo has what it takes to make a healthy baby: On average in Canada, 71 per cent of embryo transfers fail. So how do you choose which ones to bet on?
Many IVF programs decide by an embryo's looks. But more than half of all miscarriages are thought to be caused by having the wrong number of chromosomes, so these days some patients pay in the neighbourhood of $3,000 to $5,000 to have chromosomes counted. Reproductive Medicine Associates of New Jersey, for instance, has a system called SelectCCS that will test six or seven cells plucked from an embryo on its fifth day of development. Reprogenetics, another New Jersey company, has competing preimplantation tests. Canadians who opt for this have their offsprings' cells couriered down for assessment.
The hunt is on for less invasive ways to screen embryos – from time-lapse photography to analyzing embryonic secretions. But these ideas are "not anywhere near as advanced" as chromosome counting, says Dr. Matt Gysler, medical director of the Isis Regional Fertility Centre in Mississauga.
Timing is everything
The lining of the uterus, known as the endometrium, is where the embryo implants to make a pregnancy. During IVF treatment, doctors give women hormones to grow their linings to a certain thickness and quality. But sometimes embryos that look perfectly good just don't seem to want to implant in linings that also look perfectly good.
So now researchers are trying to home in on what is being called "the implantation window." A few clinics, including IVI in Spain, believe that genes expressed in the lining might hold the key. They offer a test, called ERA (for Endometrial Receptivity Array), that uses an endometrial biopsy during a mock cycle to determine whether and when a woman's uterus might be most hospitable to an embryo transfer the following month. Some Canadian doctors are already offering this test to patients, at a cost of about $900, while others say they are waiting for more evidence that it works.