Diabetes is a well-established risk factor for miscarriage. This is especially true for women with poorly controlled blood sugar.
Hyperglycemia increases the chance that the fetus will grow too large in utero, and also the odds for complications like preeclampsia and fetal neurological disorders, which are also associated with pregnancy loss.
The relationship between diabetes and miscarriage has always been regarded as straight forward. But now, a new study out of Copenhagen has scientists reevaluating the causal relationship between these two conditions.
Cohort Study Links Pregnancy Loss with Type 2
The study, which was recently published in Diabetology, used the information from a Danish cohort study to follow women born between 1957 and 1997 who went on to develop type 2 before 2017.
Each type 2 subject was matched with 10 control women born the same year with the same education level who did not develop diabetes. In total, the study looked at data from over 270,000 individuals, 24,774 of which had type 2 diabetes.
When the researchers compared miscarriage rates between the two groups, they found that women who had miscarried one or more times developed diabetes at a higher rate than those with no miscarriages.
What’s more, the risk for developing type 2 appeared to increase with each successive pregnancy loss:
- Women with one miscarriage were 18% more likely to develop type 2
- Women with two miscarriages had a 38% higher risk
- And women with three miscarriages had a 71% higher risk
While information on BMI during pregnancy for the cohort was limited, the researchers found that the elevated risk of developing type 2 held true when the calculations were adjusted for obesity.
Finding the Connection Between Miscarriage and Diabetes
While the study found a clear connection between pregnancy loss and the eventual development of type 2 diabetes, the researchers could only theorize on how and why the connection exists.
Psychological Distress and Lifestyle Changes
The most logical explanation relates to emotional, psychological, and lifestyle changes that are likely to be experienced by a woman suffering through the loss of an unborn child.
We already know from previous studies that stress, sleep duration, and weight gain play a huge role in the development of diabetes and obesity. We also know that depression and the use of antidepressants increases diabetes risk.
It isn’t a stretch to imagine that women who experience pregnancy loss are more likely to suffer through more of these conditions than women who have not had a miscarriage. But the fact that the researchers found the risk of developing diabetes was equal among obese and non-obese women makes this connection less likely.
The researchers also raise the possibility that there is some shared genetic characteristic that increases a person’s risk for both miscarriage and diabetes.
This genetic link would likely be something immunological or metabolic that affects fetal health or pregnancy hormones as well as insulin production and glucose regulation.
It is also possible that pregnancy itself triggers an immunological process that is fatal to the fetus while starting a cascade of symptoms that later triggers diabetes.
Of course, there is also the possibility that what we have always known to be true — that diabetes increases miscarriage risk — and pre-diabetes is actually all we are seeing here.
The researchers pose the theory that “prediabetic metabolic conditions” may exist long before diagnosis. And that these diabetes-related metabolic issues are actually what is causing the miscarriages.
Given what we’ve recently learned from the EarlyBird study — that blood sugar anomalies and abnormal insulin secretion are detectable decades before diabetes is diagnosed — this does not seem to be a far-fetched conclusion.
Importance of Monitoring
If pre-diabetes is the case, it only further highlights the importance of blood sugar monitoring in pregnant women.
For women who have already experienced pregnancy loss, consistent monitoring may be even more important. In these instances, early detection of elevated blood sugar or other metabolic anomalies could provide an avenue for intervention not only to save the pregnancy but to prevent the person from going on to develop diabetes in the future.