Dietary factors may play a role in the etiology of endometriosis and dietary intake of some food groups and nutrients could be associated with endometriosis risk. This systematic review and meta-analysis of observational studies was conducted to summarize the findings on the association between dietary intakes of selected food groups and nutrients (dairy, fats, fruits, vegetables, legumes, and animal-derived protein sources), and the risk of endometriosis among adult women. PubMed, Scopus, and ISI Web of Science were systematically searched up to September 2022. The inverse variance-weighted fixed-effect method was used to estimate the effect size and corresponding 95% CI. A total of 8 publications (4 studies) including 5 cohorts and 3 case-control with a sample size ranging from 156 to 116,607 were included in this study. A higher intake of total dairy [all low-fat and high-fat dairy foods] was associated with decreased risk of endometriosis (RR 0.90; 95% CI, 0.85 to 0.95; P < 0.001; I² = 37.0%), but these associations were not observed with intakes of low or high-fat dairy, cheese or milk. Increased risk of endometriosis was associated with higher consumption of red meat (RR 1.17; 95% CI, 1.08 to 1.26; P < 0.001; I² = 82.4%), trans fatty acids (TFA) (RR 1.12; 95% CI, 1.02 to 1.23; P = 0.019; I² = 73.0%), and saturated fatty acids (SFA) (RR 1.06; 95% CI, 1.04 to 1.09; P < 0.001; I² = 57.3%). The results of this meta-analysis suggest that there may be differing associations between dietary intake of dairy foods, red meat, SFAs, and TFAs and the risk of endometriosis. It may be useful to extend the analysis to other types of food groups and dietary patterns to obtain a complete picture. Additionally, further investigations are needed to clarify the role of diet in the incidence and progression of endometriosis.Trial registration: PROSPERO, CRD42020203939.

Based on a comprehensive search, we realized that the findings of the available literature are contradictory, and also limited data are available on Middle Eastern populations in terms of probiotic supplementation during the pregnancy. Therefore, the current double-blind, randomized, placebo-controlled clinical trial was carried out to investigate the effects of probiotic supplementation during pregnancy on the risk of gestational diabetes mellitus and also other maternal and neonatal outcomes. The pregnant women were randomized to either received probiotic supplement (n = 271) or placebo (n = 271) from the first half of the second trimester (14 weeks of pregnancy) up to 24 weeks when pregnant women routinely evaluated regarding the GDM. During the 24-28 weeks of pregnancy, mothers were evaluated regarding the presence of GDM using a 75 g oral glucose tolerance test (OGTT). The fasting blood glucose (FBG) was also evaluated within OGTT processes. Each 500 mg probiotic capsule was a mixture of Lactobacillus acidophilus LA1 (>7.5 × 10⁹ CFU), Bifidobacterium longum sp54 cs (>1.5 × 10⁹ CFU), and Bifidobacterium bifidum sp9 cs (>6 × 10⁹ CFU). Overall, 507 pregnant women make up our study population with a mean age of 32.03 years and a Body Mass Index (BMI) of 30.20 kg/m². There was no significant difference between the intervention and the control group regarding FBG (88.68 vs. 89.61 mg/dL; P = 0.338), OGTT-1h (163.86 vs. 166.88; mg/dL; P = 0.116), and OGTT-2h (138.39 vs. 139.27; mg/dL; P = 0.599). The incidence of GDM in the intervention group was 41.9% which was not significantly different from the control group (40.2%) (P = 0.780). Likewise, no significant difference was detected in terms of other studied parameters. It seems that probiotics supplementation of pregnant women from the first half of the second trimester up to 24 weeks of pregnancy does not reduce the risk of GDM, or improve other neonatal and maternal outcomes.