CGMs for Pregnant Women with Type 1 Diabetes are Officially Awesome

CGMs for Pregnant Women with Type 1 Diabetes are Officially Awesome

I went on my first continuous glucose monitor back in 2007, when the Dexcom system was known as the “STS” and the duration for a sensor was only three days. It also wasn’t waterproof, so I had to stick these giant saran wrap-looking shower patches over the transmitter when I bathed. And it wasn’t “dose your insulin” accurate but more “yeah, you have some bouncy blood sugars” kind of accurate.

But despite being cumbersome, it was the first glimpse I’d ever had into a streaming video version of my blood sugars – leaps and bounds better than the snapshots I was receiving from my finger sticks. I was instantly hooked on the data. It made me feel safe. And it made me feel like I had a chance at controlling this beast of a disease.

When I became pregnant with my daughter in 2009, I was already on the Dexcom Seven Plus and it was AWESOME compared to that first iteration of Dexcom. I used the data to help warn me of those epic first trimester hypos and also relied on the information to help me change my basal rates as the pregnancy-induced insulin resistance kicked in. My A1C stayed under 6.6% for my entire first pregnancy, and my daughter was born healthy, happy, and with a ton of hair. (Happy and healthy related to my hard work … the hair was just a fluke.)

Fast-forward six years to 2015, when I became pregnant with my son. This time, I was using the Dexcom G4 (the G5 was available but my endo-at-the-time preferred the data output from the G4 model) and the numbers on my Dexcom receiver were in line with my finger sticks. I was able to keep my numbers tight without dropping into too many low blood sugars, and the data from my CGM helped me achieve my goal. My A1C stayed under 6% for the duration of my pregnancy and my son was born healthy, happy, and with a ton of hair.

I can’t imagine the stress of navigating a pregnancy with type 1 diabetes without the data offered up by my CGM. I know in my heart, and in my uterus, that my health and my babies benefitted from keeping such close and careful tabs on my blood sugars.

But now I don’t need to rely on my heart, or my uterus, to prove my assumption about CGMs right. At the most recent EASD conference, the CONCEPTT study proved that CGMs for pregnant women with type 1 diabetes improve the health of both mothers and their newborns. I had a chance to talk with Marlon Pragnell, JDRF Senior Program Scientist, about the CONCEPTT study and what it means for moms with diabetes.  

“Currently, one in two babies born to mothers with type 1 diabetes has complications related to high blood glucose, including premature birth, stillbirth, a need for intensive care after birth, higher than average birth weights, and higher than average rates of pre-eclampsia and Caesarean section for mothers,” shared Marlon. “The CONCEPTT study was a JDRF-funded international multisite randomized controlled trial to determine whether the use of continuous glucose monitoring [CGM] would improve glucose control in women with T1D who are pregnant or planning pregnancy.” 

According to Marlon, the CONCEPTT study recruited 325 women with type 1 diabetes aged 18-40 who were pregnant or planning pregnancy and managing their diabetes with insulin pumps or multiple daily injections and the finger-stick method of monitoring blood glucose. Half were randomized to CGM, and half to remain on the finger-stick method. The CGM was worn for approximately 24 weeks, from 10-12 weeks until the end of their pregnancy.  The study was conducted at 31 sites that spanned Canada, UK, Spain, Italy, Ireland, and the US.

The CONCEPTT results showed that CGM during pregnancy led to significantly better health outcomes for mothers and babies and prompted the authors to call for CGM to be offered to all pregnant women with type 1 diabetes.   In an accompanying editorial to the study results, Dr. Satish Garg noted, “We believe that the CONCEPTT results support CGM use during pregnancy for all women with type 1 diabetes.” 

Marlon shared that moms using the CGM showed a “small but statistically significant -0.2% improvement in HbA1c at 34 weeks.” She said that they also spent 100 more minutes/day in range and 72 fewer minutes/day in hyperglycemia.  This to me was huge, because I remember each moment my blood sugar was above the recommended range was particularly stressful.   Anything that takes a bite out of both the stress and the potential for complications is a win.

The benefits to babies were significant. Marlon stated the findings as follows: “Mothers who wore CGM during pregnancy had smaller, healthier babies. Compared with the control group, these babies were less likely to be large for gestational age (53% vs 69%), had a lower incidence of neonatal hypoglycemia (15% vs 28%), were less likely to require NICU admissions lasting more than 24 hours (27% vs 43%), and had one-day shorter length of hospital stay (3.1 vs 4 days). These hard clinical outcomes were the most exciting results of the trial and represent the first time improvement beyond measures of glucose (such as time-in-range, hyper and hypoglycemia and HbA1c).”

The results indicated that for every 6-8 pregnant woman treated with CGM one of these negative outcomes for a baby could be prevented, stated Marlon.  “An economic analysis for cost-effectiveness is pending,” she added.

So what are the key takeaways from this study for women with type 1 diabetes who are either planning a pregnancy or currently pregnant?

“The very positive results from CONCEPTT prompted the authors to call for physicians to offer CGM to all pregnant women with type 1 using intensive insulin therapy. The CONCEPTT study was conducted with the older Medtronic Guardian sensor.  Wear time was lower than in more recent CGM studies, with ~80% of women reporting frustrations with the CGM device. Even better outcomes would be anticipated with the newer generation of more accurate and reliable sensors.”

And what’s next for the pregnancy research team at JDRF?

“Artificial pancreas systems are on the horizon and the extensive data from CONCEPTT will certainly provide valuable information on glucose control through the various stages of pregnancy in women with T1D,” shared Marion.  “Dr. Helen Murphy, one of the CONCEPTT co-primary investigators, is doing a lot of work in this area and has published positive results from a small feasibility trial of hybrid closed loop during pregnancy in NEJM in 2016. The next step will be a large multicenter randomized controlled trial. A pregnancy study with the FreeStyle Libre study is also ongoing.”

I think about my two kids and all the what ifs of pregnancy and parenting. I’m forever grateful for the addition of a CGM to my diabetes management arsenal, and I’m thrilled to see a study that strongly shows the benefits of CGM use for a  mom with diabetes and her babies. 

Kerri Sparling
Kerri Sparling

Kerri Sparling has been living with type 1 diabetes since 1986 and writes the diabetes blog She believes in diabetes advocacy, patient empowerment, and strong coffee. Kerri lives in Rhode Island with her husband, her daughter, and an unfortunate army of cats.

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