Whatever the case, she said, “what price would you place on your baby avoiding a prolonged stay in the NICU? I think [it’s] priceless.”
She added that 80% of participants reported having trouble with the devices, which she attributed to the technology being old.
As for the planned pregnancy group, the study noted that “it did not have sufficient power to detect the magnitude of differences that were significant in the pregnancy trial.”
However, Dr. Feig said the study showed a trend toward lower HbA1c levels among CGM users in this population in which “tight glycemic control is absolutely paramount,” and that other studies also provide evidence supporting CGM use through the breastfeeding period.
Dr. Feig also pointed to a similar 2013 study coauthored by Dr. Mathiesen, her debate opponent. Dr. Feig said its findings are weakened because participants used CGM intermittently. She also pointed to the low participation (64%) in CGM by women assigned to a CGM group. (Diabetes Care. 2013 Jul;36[7]:1877-83)
In that study, researchers assigned 123 Danish women with type 1 diabetes mellitus and 31 women with type 2 diabetes mellitus to use real-time CGM for 6 days at various points in pregnancy or to only engage in routine care (including self-monitored plasma glucose seven times daily).
Researchers found no difference in HbA1c levels at 33 weeks between the groups, and they found similar rates of severe hypoglycemia and perinatal outcomes such as large-for-gestational-age infants.
Dr. Elisabeth R. Mathiesen
These results, Dr. Mathiesen said, make her skeptical of a blanket recommendation to use CGM in pregnancy. Women aren’t eager to upload their glucose readings, making it difficult for doctors to make adjustments. “My women are Vikings. They come from Denmark,” she said, but “even these women don’t upload their glucose data between visits. ... I rarely have women who upload their data and look at their curves themselves. I think that’s a major disadvantage.”
Dr. Mathiesen also pointed to Dr. Feig’s study and noted that many women used CGM less than 75% of the time. In addition, 80% reported problems with the technology. “I’ve seen lots of skin problems with sensors. One lady used CGM during pregnancy; 4 years later, during another pregnancy, she showed me the mark of her sensor.”
Finally, the cost of CGM use is high considering the ongoing expense of the devices and the nurse time needed to upload data in the clinic. “As a rough estimate, the cost of CGM use in about 20 women during their pregnancies is the cost of the salary for one nurse per year,” she said.
Dr. Feig reported speaking fees from Medtronic, which provided CGM devices at reduced cost to her trial. Dr. Mathiesen reported research funding from the Novo Nordisk Foundation and speaker fees from Novo Nordisk, Lilly, AstraZeneca, and Sanofi-Aventis.