Gestational diabetes mellitus (GDM) prevalence is increasing and becoming a major public health concern. Whether a Mediterranean diet can help prevent GDM in unselected pregnant women has yet to be studied. We conducted a prospective, randomized controlled trial to evaluate the incidence of GDM with two different dietary models. All consecutive normoglycemic (<92 mg/dL) pregnant women at 8–12 gestational weeks (GW) were assigned to Intervention Group (IG, n = 500): MedDiet supplemented with extra virgin olive oil (EVOO) and pistachios; or Control Group (CG, n = 500): standard diet with limited fat intake. Primary outcome was to assess the effect of the intervention on GDM incidence at 24–28 GW. Gestational weight gain (GWG), pregnancy-induced hypertension, caesarean section (CS), preterm delivery, perineal trauma, small and large for gestational age (SGA and LGA) and admissions to neonatal intensive care unit were also assessed. Analysis was by intention-to-treat. A total of 874 women completed the study (440/434, CG/IG). According to nutritional questionnaires and biomarker analysis, women in the IG had a good adherence to the intervention. 177/874 women were diagnosed with GDM, 103/440 (23.4%) in CG and 74/434(17.1%) in IG, p = 0.012. The crude relative risk (RR) for GDM was 0.73 (95% CI: 0.56–0.95; p = 0.020) IG vs CG and persisted after adjusted multivariable analysis, 0.75(95% CI: 0.57–0.98; p = 0.039). IG had also significantly reduced rates of insulin-treated GDM, prematurity, GWG at 24–28 and 36–38 GW, emergency CS, perineal trauma, and SGA and LGA newborns (all p<0.05). An early nutritional intervention with a supplemented MedDiet reduces the incidence of GDM and improves several maternal and neonatal outcomes.

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.

Gestational diabetes mellitus (GDM) is the most frequent morbidity found in pregnancy, and it increases the risk for several maternal-fetal complications. Hispanic women are considered at high risk. The St. Carlos GDM prevention study is a randomized controlled trial (RCT) conducted from 2016–2017. Normoglycemic women were randomized at 12–14 Gestation week (WG) to an intervention group (IG) receiving recommendations based on the MedDiet (supplemented with ExtraVirgin Olive Oil/pistachios), or to a control group (CG), recommended to limit fat intake. After RCT conclusion, IG recommendations were applied to a real-world group (RW) in routine clinical practice. The primary endpoint of the current study is an assessment of the GDM rate in Hispanic participants of the aforementioned studies: 132 RCT, 128 CT, 284 RW participants. The GDM rate was lower in IG: 19/128(14.8%), p = 0.021, and RW: 38/284(13.4%), p = 0.029) than in CG: 34/132(25.8%). Adjusted RR (95%CI) for GDM: 0.72 (0.50–0.97), p = 0.037 in IG and 0.77 (0.61–0.97), p = 0.008 in RW. Rates of urinary tract infections, emergency caesarean-sections and perineal trauma were also lower in IG and RW. Other adverse outcomes were lower in IG vs. CG. In conclusion, a MedDiet-based intervention reduces the rate of GDM and several adverse maternal-fetal outcomes in Hispanic women residing in Spain.

A prenatal diet affects materno-foetal outcomes. This is a post hoc analysis of the St. Carlos gestational diabetes mellitus (GDM) Prevention Study. It aims to evaluate the effect of a late first-trimester (>12 gestational weeks) degree of adherence to a MedDiet pattern—based on six food targets—on a composite of materno-foetal outcomes (CMFCs). The CMFCs were defined as having emergency C-section, perineal trauma, pregnancy-induced hypertension and preeclampsia, prematurity, large-for-gestational-age, and/or small-for-gestational-age. A total of 874 women were stratified into three groups according to late first-trimester compliance with six food targets: >12 servings/week of vegetables, >12 servings/week of fruits, 3 servings/week of nuts, >6 days/week consumption of extra virgin olive oil (EVOO), and ≥40 mL/day of EVOO. High adherence was defined as complying with 5–6 targets; moderate adherence 2–4 targets; low adherence 0–1 targets. There was a linear association between high, moderate, and low adherence, and a lower risk of GDM, CMFCs, urinary tract infections (UTI), prematurity, and small-for-gestational-age (SGA) newborns (all p < 0.05). The odds ratios (95% CI) for GDM and CMFCs in women with a high adherence were 0.35((0.18–0.67), p = 0.002) and 0.23((0.11–0.48), p < 0.001), respectively. Late first-trimester high adherence to the predefined six food targets is associated with a reduction in the risk of GDM, CMFCs, UTI, prematurity, and SGA new-borns.

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 (HbA_1c) levels at 36–38 GWs in GDMw and women with normal glucose tolerance (NGTw). Results: GDMw as compared with NGTw had higher HbA_1c 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.

Aims: The aim of the study was to evaluate the effect of a Mediterranean diet (MedDiet), enhanced with extra virgin olive oil (EVOO) and nuts, on a composite of adverse maternofoetal outcomes of women with normoglycemia during pregnancy. Methods: This was a sub-analysis of the St Carlos gestational diabetes mellitus Prevention Study. Only normoglycemic women were analysed (697). They were randomized (at 8–12th gestational weeks) to: standard-care control group (337), where fat consumption was limited to 30% of total caloric intake; or intervention group (360), where a MedDiet, enhanced with EVOO and pistachios (40–42% fats of total caloric intake) was recommended. The primary outcome was a composite of maternofoetal outcomes (CMFOs): at least having 1 event of emergency C-section, perineal trauma, pregnancy-induced hypertension and preeclampsia, prematurity, large-for-gestational-age and small-for gestational-age. Results: Crude relative risk showed that the intervention was associated with a significant reduction in the risk of CMFOs (0.48 [0.37–0.63]; p = 0.0001), with a number-needed-to-treat = 5. Risk of urinary tract infections, emergency C-sections, perineal trauma, large-for-gestational-age and small-for gestational age new-borns were also significantly reduced. Conclusion: A MedDiet, enhanced with EVOO and nuts, was associated with a risk reduction of CMFOs in over 50% in normoglycemic pregnant women. Therefore, it might be a potentially adequate diet for pregnant women. Trial registration: Identifier ISRCTN84389045. The study was registered on September 27, 2013. Last edited on September 26, 2018