Embryo Screening Gives Hope for Recurrent Miscarriage
If you treat patients who are trying to conceive, you are well aware of this statistic: nearly 20 percent of all pregnancies end in miscarriage. What’s even more frustrating for clinicians, and devastating for patients, is that 50 to 75 percent of recurrent pregnancy loss has been considered idiopathic – until recently.
An expanded clinical application of Pre-Implantation Genetic Screening (PGS) has greatly reduced miscarriage rates, and is now available for your patients through Dr. Gehlbach, a reproductive endocrinologist on staff at North Kansas City Hospital.
“Until we discovered a chromosomal link, we had no way to help these patients,” says Dr. Gehlbach, who also sees patients at his practice, Midwest Reproductive Center, on the North Kansas City Hospital campus. “We had no explanatory factor.”
Researchers Discover Chromosomal Link for Miscarriage
Previously, fertility specialists attributed recurrent miscarriages that are diagnosable to a handful of factors, including:
- Abnormal uterine cavities
- Antiphospholipid syndrome
- Abnormal parental karyotypes
- Hormonal and metabolic factors
- Lifestyle variables
But that still left the idiopathic cases, until researchers made a key chromosomal discovery: Those patients were producing higher levels of aneuploid embryos.
“That’s a big change in our thinking,” Dr. Gehlbach says. “Those patients have plenty of eggs to produce embryos, but the majority aren’t going to be healthy pregnancies.”
How PGS Works
A patient with suspected idiopathic recurrent miscarriage undergoes in-vitro fertilization — not a standard step for such cases in the past.
Dr. Gehlbach’s embryologist performs a blastocyst biopsy on the patient’s embryos and then sends the cells to an outside lab for PGS using array comparative genomic hybridization (aCGH) to look for chromosomal duplications or deletions.
Dr. Gehlbach receives the results within 24 hours, then transfers unaffected embryos to the patient. The cell biopsy does not have a detrimental effect on embryo implantation.
PGS Uses Expanding Nationwide
Dr. Gehlbach has performed PGS for three years at his practice for other indications. It is primarily used to identify embryos with chromosomal abnormalities, such as Down’s Syndrome or Edward’s Syndrome (Trisomy 16). It has only been within the past year and a half that he has expanded the clinical application to treat patients with idiopathic recurrent miscarriage.
Fertility specialists are not sure why so many embryos are abnormal in patients enduring recurrent miscarriage, but genetic screening results have been encouraging.
A 2012 study on idiopathic recurrent miscarriage published in the American Society for Reproductive Medicine's journal Fertility and Sterility showed the use of PGS greatly improved the miscarriage rate to a residual 6.9 percent for recurrent pregnancy loss patients, compared to 33.5 percent in the control group.
Although there have not been randomized, controlled trials yet on the expanded screening application, its use is growing nationwide and several observational studies have shown a clinical benefit.
Dan Gehlbach, MD
After medical school at the University of Kansas, Dr. Gehlbach completed an OB/GYN residency at William Beaumont Army Medical Center in El Paso, Texas, and a reproductive endocrinology fellowship at The Johns Hopkins Hospital. Dr. Gehlbach is board-certified in infertility, obstetrics and gynecology and reproductive endocrinology.
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