Diabetes in early pregnancy: getting to the heart of the matter

What is the "cost" of reducing adverse pregnancy outcomes in patients with gestational diabetes mellitus - risk factors for perinatal complications in a retrospective cohort of pregnant women with GDM

BACKGROUND

Gestational diabetes mellitus (GDM) is a frequent pregnancy complication, affecting the maternal and neonatal health. The new diagnostic strategy for GDM, proposed by the International Association of Diabetes and Pregnancy Study Groups in 2010 and World Health Organization in 2013, raised hope to reduce perinatal complications. The purpose of the study was to compare risk factors influencing maternal and foetal outcomes in a group of pregnant women diagnosed with GDM, and in a group of pregnant women without GDM, regardless of the adopted diagnostic criteria. Also, the aim of the study was to evaluate the impact of risk factors on perinatal results and the "cost" of reducing adverse pregnancy outcomes in patients with GDM.

METHODS

It was a retrospective study based on the analysis of births given after 37 weeks of pregnancy at the 2nd Department of Obstetrics and Gynaecology, Warsaw Medical University during the years 2013 to 2015. All pregnant women had a 75 g OGTT between the 24th and 28th weeks of pregnancy. The study compared risk factors for perinatal complications in 285 GDM patients and in 202 randomly selected women without GDM. The impact of selected risk factors on perinatal outcomes was analysed.

RESULTS

Both the diagnosis of GDM and maternal BMI prior to pregnancy, significantly modified the risk of excessive and insufficient weight gain during pregnancy. The parameters significantly influencing the risk of the composite adverse maternal outcome were the maternal abdominal circumference [OR: 1.08 (1.04; 1.11)] and multiparity, which reduced the risk by almost half [OR: 0.47 (0.30; 0.75)]. The maternal abdominal circumference before the delivery was a strong factor correlating with the occurrence of perinatal complications in both the mother and the foetus in the entire cohort. A circumference over 100 cm increased the risk of at least one maternal complication (increased blood loss, soft tissue injury, pre-eclampsia) by almost 40% (OR 1.38, p < 0.001).

CONCLUSIONS

No differences were found in maternal and foetal outcomes in GDM and non-GDM women except gestational weight gain below Institute of Medicine recommendations. The only "cost" of reducing adverse pregnancy outcomes in GDM patients seems to be lowering gestational weight gain, the future impact of which on GDM pregnant population should be assessed. The maternal abdominal circumference measured before delivery not the severity of carbohydrate intolerance, remained the main predictor for significant perinatal complications.

Embryonic nutritional hyperglycemia decreases cell proliferation in the zebrafish retina

Diabetic retinopathy (DR) is one of the leading causes of blindness in the world. While there is a major focus on the study of juvenile/adult DR, the effects of hyperglycemia during early retinal development are less well studied. Recent studies in embryonic zebrafish models of nutritional hyperglycemia (high-glucose exposure) have revealed that hyperglycemia leads to decreased cell numbers of mature retinal cell types, which has been related to a modest increase in apoptotic cell death and altered cell differentiation. However, how embryonic hyperglycemia impacts cell proliferation in developing retinas still remains unknown. Here, we exposed zebrafish embryos to 50 mM glucose from 10 h postfertilization (hpf) to 5 days postfertilization (dpf). First, we confirmed that hyperglycemia increases apoptotic death and decreases the rod and Müller glia population in the retina of 5-dpf zebrafish. Interestingly, the increase in cell death was mainly observed in the ciliary marginal zone (CMZ), where most of the proliferating cells are located. To analyze the impact of hyperglycemia in cell proliferation, mitotic activity was first quantified using pH3 immunolabeling, which revealed a significant decrease in mitotic cells in the retina (mainly in the CMZ) at 5 dpf. A significant decrease in cell proliferation in the outer nuclear and ganglion cell layers of the central retina in hyperglycemic animals was also detected using the proliferation marker PCNA. Overall, our results show that nutritional hyperglycemia decreases cellular proliferation in the developing retina, which could significantly contribute to the decline in the number of mature retinal cells.

Effect of pregestational diabetes mellitus on first trimester placental characteristics: three-dimensional placental volume and power Doppler indices

OBJECTIVE

To investigate whether pregestational diabetes mellitus (DM) induces changes in vascular placental development detectable at first trimester.

METHODS

This was a prospective case-control study in 69 women with pregestational DM and 94 controls undergoing first-trimester combined screening for aneuploidies. Maternal characteristics, fetal nuchal translucency thickness, maternal serum pregnancy-associated plasma protein A (PAPP-A) and free β human chorionic gonadotrophin (β-hCG) were evaluated. Three-dimensional ultrasound was used to measure placental volume and three dimensional power Doppler (3D-PD) placental vascular indices including: vascularization index (VI), flow index (FI) and vascularization flow index (VFI). Pregnancy-associated hypertensive complications (PAHC) and perinatal outcomes were analyzed. The total group of diabetic women and the group of diabetic women without PAHC were compared separately with the control group.

RESULTS

3D-PD placental vascular indexes were significantly lower in women with DM than in controls (VI p = 0.007, FI p = 0.003 and VFI p = 0.04). These differences remained on excluding cases with PAHC in the DM group. No differences were found in placental volumes between the DM group and controls. Serum PAPP-A levels were also lower in diabetic women (p < 0.02) and negatively correlated with the degree of maternal metabolic control at first trimester.

CONCLUSIONS

Pregestational DM induces demonstrable alterations in first trimester placental development, with significantly reduced placental vascularization indices and PAPP-A values. This effect is independent of the later development of PAHC.