Effect of different Hb concentrations on the risk of gestational diabetes mellitus in women with thalassemia minor

Backgrounds: A few studies have focused on the effect of thalassemia and different Hb levels on pregnancy outcomes recently. However, to our knowledge, there are no studies on the effects of different levels of hemoglobin(Hb) on pregnancy outcomes in Chinese women with thalassemia minor. In the present research, we aimed to clarify the effect of different Hb levels on pregnancy outcomes and to further explore the association of different Hb levels and gestational diabetes mellitus (GDM) in pregnant women with thalassemia minor in Chinese populations. Methods A retrospective controlled study was conducted on 723 pregnant women who were followed up for delivery in our hospital from 2017 to 2021. They were grouped into thalassemia minor and control group. The two groups were further divided into three subgroups, including anmia, normal and high Hb subgroups. Pregnant complications were studied in two main groups and their three subgroups. All statistical analyses were performed using R version 4.1.0 and contributed packages. Results There were no significant differences regarding neonatal and maternal pregnancy outcomes in women with and without thalassemia except for postpartum anemia. Furthermore, in the thalassemia group, the prevalence of GDM in the high Hb subgroup was significantly higher than the other two subgroups. However, in the control group, no significant statistical differences were found among the three subgroups. Moreover, in the high Hb subgroup, the fetuses of women with thalassemia were more likely to develop jaundice after birth. In the normal Hb subgroup, the proportion of macrosomia in the thalassemia group was significantly higher than the control group, while the proportion of low birth weight infants was on the contrary. Lastly, in anemia subgroups, we found less pregnant women with thalassemia suffered from cesarean compared to pregnant women without thalassemia. Conclusion We concluded that high Hb concentration might be a trigger for GDM in Chinese pregnant women with thalassemia minor. Maternal iron and Hb levels should be monitored during antenatal care and pregnancy management, as iron supplementation may lead to adverse pregnancy outcomes in women with thalassemia minor with normal or particularly high Hb concentrations.