A systematic review and meta-analysis 2 evaluating the association between dietary patterns and gestational diabetes (GDM) included 13 cohort studies. Dietary patterns with high levels of whole grain, fruits, vegetables, and low fat dairy intake decreased the risk of GDM: "vegetable based diet" (RR 0.86, 95% CI 0.76 to 0.98), and "Mediterranean" (RR 0.71, 95% CI 0.56 to 0.91). However, the western dietary pattern, determined by high intakes of red meat, process meat, fried food, and refined grain could increase the risk of GDM (RR 1.27, 95% CI 1.03 to 1.56).
A multicentre trial 3 assessing whether a Mediterranean-style diet reduces adverse pregnancy outcomes randomized 1 252 high-risk women. Mediterranean-style diet include high intake of nuts, extra virgin olive oil, fruits, vegetables, nonrefined grains, and legumes; moderate to high consumption of fish; low to moderate intake of poultry and dairy products; low intake of red and processed meat; and avoidance of sugary drinks, fast food, and food rich in animal fat versus usual care. Participants received individualised dietary advice at 18, 20, and 28 weeks' gestation. Women in the intervention arm consumed more nuts (70% versus 23%; and extra virgin olive oil (93% versus 49%; than controls; increased their intake of fish (p < 0.001), white meat (p < 0.001), and pulses (p = 0.05); and reduced their intake of red meat (p < 0.001), butter, margarine, and cream (p < 0.001). There was no significant reduction in the composite maternal outcomes (GDM or preeclampsia). However, there was an apparent reduction in the odds of gestational diabetes by 35% (aOR 0.65, 95% CI 0.47 to 0.91, p = 0.01). Mothers gained less gestational weight (mean 6.8 versus 8.3 kg; adjusted difference -1.2 Kg, 95% CI -2.2 to -0.2, p = 0.03) with intervention versus control.
In another RCT 4 600 normoglycaemic Hispanic women in high risk of GDM were randomized at 12-14 gestation week to an intervention group (IG) receiving recommendations based on the Mediterranean diet (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 GDM rate was lower in IG: 19/128 (14.8%), and RW: 38/284 (13.4%) than in CG: 34/132(25.8%). Adjusted RR (95%CI) for GDM: 0.72 (0.50 to 0.97), p = 0.037 in IG and 0.77 (0.61 to 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.
A systematic review and meta-analysis 5 evaluating the association of different types of diet and physical activity-based antenatal lifestyle interventions with gestational weight gain (GWG) and maternal and neonatal outcomes included 117 RCTs with a total of 34 546 women. Compared with routine care, diet was associated with less GWG (-2.63 kg; 95% CI, -3.87 to -1.40) than physical activity (-1.04 kg; 95% CI, -1.33 to -0.74) or mixed interventions (eg, unstructured lifestyle support, written information with weight monitoring, or behavioral support alone) (-0.74 kg; 95% CI, -1.06 to -0.43). Diet was associated with reduced risk of GDM (OR, 0.61; 95% CI, 0.45 to 0.82), preterm delivery (OR, 0.43; 95% CI, 0.22 to 0.84), large for gestational age neonate (OR, 0.19; 95% CI, 0.08 to 0.47), neonatal intensive care admission (OR, 0.68; 95% CI, 0.48 to 0.95), and total adverse maternal (OR, 0.75; 95% CI, 0.61 to 0.92) and neonatal outcomes (OR, 0.44; 95% CI, 0.26 to 0.72). Diet with physical activity was associated with reduced GWG (-1.35 kg; 95% CI, -1.95 to -0.75) and GDM (OR, 0.72; 95% CI, 0.54 to 0.96) and total adverse maternal outcomes (OR, 0.81; 95% CI, 0.69 to 0.95).
A Cochrane review [Abstract] 1 included 11 studies with a total of 2786 subjects. Dietary advice interventions versus standard care (6 trials): A trend towards a reduction in gestational diabetes mellitus (GDM) was observed for women receiving dietary advice (table T1). While no clear difference was observed for pre-eclampsia a reduction in pregnancy-induced hypertension and in gestational weight gain was observed (tableT1). None of the trials reported on large-for-gestational age or neonatal mortality and morbidity.Physiological outcomes (oral glucose tolerance test, birth weight) did not differ in one trial (n=25) comparing high-fibre diet with control. Low glycaemic index diet compared to high glycaemic index diet (4 trials): No clear differences were shown in the risks of GDM, large for gestational age infants, caesarean section, or gestational weight gain.
| Outcome | Relative effect(95% CI) | Risk with standard care - Control | Risk with dietary advice interventions - Intervention (95% CI) | No of participants(studies) Quality of evidence |
|---|---|---|---|---|
| Gestational diabetes | RR 0.60(0.35 to 1.04) | 126 per 1000 | 76 per 1000(44 to 131) | 1279(5) Very Low |
| Hypertensive disorders of pregnancy (pregnancy-induced hypertension) | RR 0.30(0.10 to 0.88) | 98 per 1000 | 29 per 1000(10 to 86) | 282(2) Low |
| Hypertensive disorders of pregnancy (pre-eclampsia) | RR 0.61(0.25 to 1.46) | 84 per 1000 | 51 per 1000(21 to 123) | 282(2) Low |
| Caesarean section | RR 0.98(0.78 to 1.24) | 300 per 1000 | 294 per 1000(234 to 372) | 1194(4) Low |
| Gestational weight gain (kg) | MD -4.70 (-8.07 to -1.34) | The mean gestational weight gain in the intervention group was 4.7 kg less (- 8.07 kg to - 1.34 kg ) | 1336(5) Low | |
Comment: The quality of evidence is downgraded by study quality.
Primary/Secondary Keywords