Dietary habits resembling Western style, rich in animal protein and poor in fruit and vegetables, increase the body acid load, a predictor of type 2 diabetes risk. Recently, the studies related to relationships between dietary acid load and insulin resistance has become a growing interest but there are only a few study conducted with gestational diabetes mellitus (GDM). Therefore, the aim of this study was to evaluate the potential relationship between dietary acid load in second trimester, blood lipid profiles and GDM.

This cross-sectional study conducted with 40 women with GDM diagnosed with two-step 100g oral glucose tolerance test and 40 healthy women, aged 21-41 years, between weeks of 14-28 of pregnancy, who attended the Department of Obstetrics and Gynecology of Gulhane Training and Research Hospital. Participants with polycystic ovary syndrome, chronic diseases, pre-GDM, or multiple pregnancies were excluded. Sociodemographic information was recorded via questionnaire and anthropometrics of women were measured.

Blood samples were taken after an overnight fasting. Dietary information was obtained by mean intakes of a 3-day food records (2 weekdays and 1 weekend day) and analyzed via nutrition analysis software. According to the data obtained from software analysis, animal protein (g/day) to potassium (g/day) ratio (AP/K), potential renal acid load (PRAL; mEq/day) score and net endogenous acid production (NEAP; mEq/day) were calculated from established algorithms to estimate dietary acid load. All nutrients were age and energy- adjusted before being introduced into the equation and tertiles of the scores were used for statistical analysis. ANOVA, ANCOVA and Logistic regression test were used. The study plan was approved by the Hospital's Ethics Committee.

Inclusion Criteria:

• Singleton pregnancy,
• Aged in 20-40 years,
• Gestational age 24-28 weeks,
• Non-history of acute or chronic diseases.

Exclusion Criteria:

• History of GDM,
• Type 1 and 2 diabetes mellitus,
• Preeclampsia,
• Polycystic ovary syndrome,
• Thyroid disease
• Parathyroid disease,
• Metabolic bone disease,
• Kidney disease,
• Abnormal liver function,
• Multiple pregnancy
• Extreme values of energy intake in their dietary records (<1500 and >4000 kkal).

In this observational cross-sectional study, 40 women with GDM and 40 healthy pregnant between 21-41 years in age, in their 24-28th gestational week applied to Gulhane Education and Research Hospital were recruited. This study must recruit 40 women for each group to have 80% study power with 5% type I error level to detect a clinically significant difference.