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.

The intrauterine environment may be related to the future development of chronic diseases in the offspring. The St. Carlos gestational diabetes mellitus (GDM) prevention study, is a randomized controlled trial that evaluated the influence of the early (before 12th gestational week) Mediterranean diet (MedDiet) on the onset of GDM and adverse gestational outcomes. Out of 874 women assessed after delivery (440 control group (CG)/434 intervention group (IG)), 703 children were followed (365/338; CG/IG), with the aim to assess whether the adherence to a MedDiet during pregnancy induces health benefits for the offspring during the first two years of life. Logistic regression analysis showed that the IG in children of mothers with pre-gestational body mass index (BMI) < 25 kg/m² and normal glucose tolerance (NGT), was associated with a lower risk (RR(95% CI)) of suffering from severe events requiring hospitalization due to bronchiolitis/asthma (0.75(0.58–0.98) and 0.77(0.59–0.99), respectively) or other diseases that required either antibiotic (0.80(0.65–0.98) and 0.80(0.65–0.99), respectively), corticosteroid treatment (0.73(0.59–0.90) and 0.79(0.62–1.00) respectively) or both (all p < 0.05). A nutritional intervention based on the MedDiet during pregnancy is associated with a reduction in offspring’s hospital admissions, especially in women with pre-gestational BMI < 25 kg/m² and NGT.

There is sparse evidence for the impact of gene-diet interaction on gestational diabetes mellitus (GDM) onset. Recent findings have shown that late first-trimester high adherence to a Mediterranean diet (MedDiet) pattern is associated with a GDM risk reduction. The aim of this study was to investigate if this effect could be modulated by TCF7L2 rs7903146 polymorphism. Research design and methods: A total of 874 pregnant women participants in the St Carlos GDM prevention study, were stratified into three groups defined as “High,5–6 on targets”, “Moderate, 2–4 on targets” or “Low, 0–1 on targets” adherence to Mediterranean diet according to late first-trimester compliance with six food targets: >12 servings/week of vegetables, >12 pieces/week of fruits, 3 servings/week of nuts, >6 days/week and >40 mL/day consumption of extra virgin olive oil. All patients were genotyped for rs7903146 using Taqman technology. Logistic regression analysis revealed that the risk of developing GDM in those with high adherence versus low adherence was significantly reduced only in carriers of the T-allele (CT + TT), with an adjusted odds ratio of 0.15 (95% CI:0.05–0.48). This effect was not observed in CC carriers. Interaction analysis yielded significant rs7903146-MedDiet interaction in GDM risk (p < 0.03) Women carrying the rs7903146 T-allele who highly adhere to a MedDiet early in pregnancy have lower risk of developing GDM than CC carriers. This reinforces the importance of identifying patients at risk of GDM who would be especially sensitive to nutritional interventions based on their genetic characteristics.

A Mediterranean diet (MedDiet)-based intervention reduces the rate of immediate postpartum maternal metabolic disorders. Whether these effects persist long-term remains to be determined. A total of 2526 normoglycemic women were randomized before the 12th gestational week (GW). IG women followed a MedDiet with extra virgin olive oil (EVOO) (>40 mL/day) and a handful of nuts daily, whereas CG women had to restrict all kinds of dietary fat. At 3 months postpartum, a motivational lifestyle interview was held. The endpoint of the study evaluated the rate of abnormal glucose regulation (AGR) and metabolic syndrome (MetS) at 3 years postpartum in women of the San Carlos cohort. A total of 369/625 (59%) CG women and 1031/1603 (64.3%) IG women were finally analyzed. At 3 months and 3 years postdelivery, the IG women showed higher adherence to the MedDiet, which was associated with lower values of body mass index (BMI) and lipid and glycemic profiles. Body weight change and waist circumference were lower in the IG women. After applying multiple regression analysis, the ORs (95%CI) resulted in AGR (3.18 (2.48–4.08); p < 0.001)/MetS (3.79 (1.81–7.95); p = 0.001) for women with GDM and higher OR for development of MetS in CG women (3.73 (1.77–7.87); p = 0.001). A MedDiet-based intervention early in pregnancy demonstrated persistent beneficial effects on AGR and MetS rates at 3 years postpartum.