According to published figures, the average fertility clinic has an in vitro fertilization (IVF) success rate of only 20-30 percent, but new techniques could boost success rates to around 50 percent. The New York Times reported that chromosomal testing and time-lapse imaging are the new techniques now being used by fertility clinics.
The chromosomal testing is called preimplantation genetic screening (PGS). This is different from preimplantation genetic diagnosis, which tests embryos for specific mutations with the goal of preventing genetic diseases. With chromosomal screening, the goal is to improve birthrates.
With PGS, one or more cells are removed from an embryo to test for chromosomal normalcy. Advanced Fertility Center of Chicago said that to a great extent, chromosomal abnormalities are responsible for failure of implantation of IVF embryos.
With time-lapse imaging, images of the embryos are taken every five minutes or so for the first three days. An algorithm calculates a score determining the embryo’s fitness based on the timing of certain events, such as how long it takes cells to divide.
Currently there is no published data proving this technique improves pregnancy and live birthrates. Some experts warn that the new techniques are being heavily promoted without data to support the idea that they truly improve pregnancy rates.
Then there’s the cost. Preimplantation genetic screening can range from $4000 to $8000, on top of IVF costs. Time-lapse imaging can add up to $1,500 or more.
Earlier generations of PGS were used for nearly 10 years, until a 2007 randomized clinical trial showed that testing actually decreased pregnancy chances.
One reason for this may be that it’s possible the testing itself damaged some embryos. Plus the test could only assess less than half of the 23 chromosome pairs, so results weren’t always accurate.
PGS proponents say the new techniques can now assess all 23 chromosome pairs. In addition, a recent UK study looked deeper into chromosomal testing.