Effectiveness of Following Mediterranean Diet Recommendations in the Real World in the Incidence of Gestational Diabetes Mellitus (GDM) and Adverse Maternal-Foetal Outcomes: A Prospective, Universal, Interventional Study with a Single Group. The St Carlos Study

We reported that a Mediterranean Diet (MedDiet), supplemented with extra-virgin olive oil (EVOO) and pistachios, reduces GDM incidence and several other adverse outcomes. In order to assess its translational effects in the real world we evaluated the effect of MedDiet from 1st gestational visit in GDM rate compared with control (CG) and intervention (IG) groups from the previously referred trial. As secondary objective we also compared adverse perinatal outcomes between normoglycemic and diabetic women. This trial is a prospective, clinic-based, interventional study with a single group. 1066 eligible normoglycaemic women before 12 gestational weeks were assessed. 932 women (32.4 ± 5.2 years old, pre-gestational BMI 22.5 ± 3.5 kg/m2) received a motivational lifestyle interview with emphasis on daily consumption of EVOO and nuts, were followed-up and analysed. Binary regression analyses were used to examine the risk for each pregnancy outcome, pregnancy-induced hypertension, preeclampsia, gestational weight gain (GWG), caesarean-section, perineal trauma, preterm delivery, small (SGA) and large for gestational age (LGA), and Neonatal Intensive Care Unit admissions. GDM was diagnosed in 13.9%. This rate was significantly lower than the CG: RR 0.81 (0.73-0.93), p < 0.001 and no different from the IG: RR 0.96 (0.85-1.07), p = 0.468. GWG was lower in diabetic women (10.88 ± 6.46 vs. 12.30 ± 5.42 Kg; p = 0.013). Excessive weight gain (EWG) was also lower in GDM [RR 0.91 (0.86-0.96); p < 0.001] without a significant increase of insufficient weight gain. LGA were also lower (1 (0.8%) vs. 31 (3.9%); p < 0.05)), and SGA were similar (5 (3.8%) vs. 30 (3.7%)). LGA were associated to EWG (RR 1.61 (1.35-1.91), p < 0.001). Differences in other maternal-foetal outcomes were not found. In conclusions an early MedDiet nutritional intervention reduces GDM incidence and maternal-foetal adverse outcomes and should be universally applied as 1st line therapy. GDM might not be consider as a high risk pregnancy any longer.

Medical nutrition therapy for gestational diabetes mellitus based on Mediterranean Diet principles: a subanalysis of the St Carlos GDM Prevention Study

OBJECTIVES

To assess whether Mediterranean Diet (MedDiet)-based medical nutrition therapy facilitates near-normoglycemia in women with gestational diabetes mellitus (GDMw) and observe the effects on adverse pregnancy outcomes.

RESEARCH DESIGN AND METHODS

This is a secondary analysis of the St Carlos GDM Prevention Study, conducted between January and December 2015 in Hospital Clínico San Carlos (Madrid, Spain). One thousand consecutive women with normoglycemia were included before 12 gestational weeks (GWs), with 874 included in the final analysis. Of these, 177 women were diagnosed with gestational diabetes mellitus (GDM) and 697 had normal glucose tolerance. All GDMw received MedDiet-based medical nutrition therapy with a recommended daily extra virgin olive oil intake ≥40 mL and a daily handful of nuts. The primary goal was comparison of hemoglobin A1c (HbA1c) levels at 36-38 GWs in GDMw and women with normal glucose tolerance (NGTw).

RESULTS

GDMw as compared with NGTw had higher HbA1c levels at 24-28 GWs (5.1%±0.3% (32±0.9 mmol/mol) vs 4.9%±0.3% (30±0.9 mmol/mol), p=0.001). At 36-38 GWs values were similar between the groups. Similarly, fasting serum insulin and homeostatic model assessment insulin resitance (HOMA-IR) were higher in GDMw at 24-28 GWs (p=0.001) but became similar at 36-38 GWs. 26.6% of GDMw required insulin for glycemic control. GDMw compared with NGTw had higher rates of insufficient weight gain (39.5% vs 22.0%, p=0.001), small for gestational age (6.8% vs 2.6%, p=0.009), and neonatal intensive care unit admission (5.6% vs 1.7%, p=0.006). The rates of macrosomia, large for gestational age, pregnancy-induced hypertensive disorders, prematurity and cesarean sections were comparable with NGTw.

CONCLUSIONS

Using a MedDiet-based medical nutrition therapy as part of GDM management is associated with achievement of near-normoglycemia, subsequently making most pregnancy outcomes similar to those of NGTw.