Letter to editor in response to “Clinical features of overt versus diagnosed pre-existing diabetes in pregnancy”

Dear Editor,

I recently read with great interest the article by Fujikawa Shingu et al.¹ titled, “Clinical features of overt versus diagnosed pre-existing diabetes in pregnancy”. The study offers an interesting viewpoint on the comparison of clinical differences between overt and diagnosed pre-existing diabetes in pregnancy. The authors done an impressive job, but certain methodological elements of the study need further refinement to further strengthen the study's findings.

First, the authors relied on a very small sample size of the pre-existing diabetic group, comprising 61 women compared to 1,084 in the overt diabetes group. This small sample size may restrict statistical power and produce false-positive results. As Hackshaw mentioned in his article that small studies can provide results quickly, they typically do not deliver reliable or precise estimates².

Second, in the overt group in pregnancy, there was an absence of pre-pregnancy glycemic control data, which could influence the interpretation of perinatal complication risks as mentioned by Wendland et al. in their study regarding the significance of glycemic control before and throughout pregnancy in mitigating risks such as perinatal complications and congenital anomalies. They noted that the WHO and the IADPSG criteria for gestational diabetes mellitus (GDM) have identified women at a slightly elevated risk for adverse pregnancy outcomes³.

Furthermore, no clinical or behavioral confounder data including diet, exercise, and patient's education are mentioned. These factors can significantly influence maternal glycemic control and perinatal outcomes, as mentioned by Xu et al.⁴ in their article⁴. Without accounting these confounders, it is difficult to understand contributors to adverse pregnancy outcomes and to interpret the differences observed between the overt and pre-existing diabetes groups.

In conclusion, although the study offers important insights in the medical field, addressing the limitations such as small sample size, absence of pre-pregnancy glycemic data and lack of confounders could enhance the robustness of the findings. We appreciate the author's contribution to this significant topic.

None.

The authors declare no conflict of interest.

Approval of the research protocol: None.

Informed consent: None.

Registry and the registration no. of the study/trial: None.

Animal studies: None.