Association between pregnancy interval and diagnosis of gestational diabetes

A recent cohort published in International Journal of Gynecology & Obstetrics thoroughly examined the association between interpregnancy interval (IEG) and gestational diabetes (GDM) from 2004 to 2018 using Finnish medical records. GDM is multifactorial and is one of the main complications of pregnancy, affecting the maternal-fetal binomial. Previous cohort studies evaluating this association in Australia and the USA have had discordant results.

Read too: Association of interpregnancy interval with adverse pregnancy outcomes

47,078 women with two previous pregnancies and who underwent an oral glucose tolerance test of 75 grams for 2 hours during their pregnancies were selected. These were divided into three IEG groups (short: 0–11 months, normal: 12–47 months and long: more than 48 months).

Study results on gestational diabetes (GDM) and IEG

Of the total, 9,975 women had short IEG, 33,075 had normal IEG and 4,659 women had long IEG. The mean age was 28.81 years for short IEG and 32.73 for long IEG (P < 0.001). The mean body mass index (BMI) was higher in women with long IEG (28.41 kg/m²), followed by short IEG (28.07 kg/m²) and normal IEG (27.18 kg/m²) (P < 0.001). Long IEG (18.24%, 95% CI 17.0–19.5) had a higher proportion of smokers and a higher rate of GDM diagnosis (27.52%, 95% CI 26.03%–29. 07%), followed by IEG 11–47 months (20.01%, 95% CI 19.53%–20.49%) and IEG 0–11 months (19.91%, 95% CI 19.05% –20.82%).

There is no difference when women with short IEG were compared with those with normal IEG (ORa 0.99, 95% CI 0.93–1.05). Women with long IEG were more likely to develop GDM when compared to women with normal IEG (ORa 1.28, 95% CI 1.19–1.38). In the logistic regression model for continuous IEG, the overall odds for developing GDM increased as IEG increased (ORa 1.05 per year, 95% CI 1.03–1.06).

See more: Gestational diabetes mellitus (GDM) [vídeo]

Conclusions

The chances of developing GDM increased as IEG increased. Among women with a GAI of less than 1 year, the proportion of GDM was notably higher than that of women with a GAI of 1 to 4 years. However, after adjusting the model, we found no evidence of a difference in the risk for developing GDM. However, it is still unknown whether prolonged IEG, as a risk factor for the development of GDM, is actually caused by some pathophysiological process, or just caused by underlying factors among these women. In this study, although the model was adjusted for maternal age, BMI and smoking, other variables that were not considered could influence the relationship between IEG and the risk of developing GDM.

Practical messages

The chances of developing GDM increased as IEG increased, especially among women with long IEG (over 47 months). The article reinforces the importance of making the correct diagnosis of gestational diabetes, as well as the importance of healthy lifestyle habits and lifestyle changes for its prevention.