The relationship between first trimester maternal diet and early pregnancy loss: a retrospective case-control study

Early pregnancy loss (EPL) is a global public health concern with significant physical and psychological effects on individuals and society. The specific etiology of many EPL cases is not well understood, and first trimester maternal diet may play a role in EPL occurrence. This study aimed to examine the differences in first trimester maternal nutrient intake, nutritional habits and nutritional knowledge levels between healthy pregnant women and women who experienced EPL.

A single center retrospective case-control study was conducted at a public hospital in Istanbul, Turkey between May-October 2024. The case group comprised 65 women who experienced first-time pregnancy loss. The control group included 65 healthy pregnant women in the first trimester without a previous PL history, with both groups matched for age, body mass index (BMI) and parity. Data were collected from the participants regarding their general information, dietary habits, the Quantitative Food Frequency Questionnaire (QFFQ), and the Nutrition Knowledge Level Scale for Adults (NKLSA). Dietary nutrient intakes were evaluated on the basis of the Dietary Reference Intakes (DRI) values and compared between the two groups. To further investigate the link between specific dietary nutrient intakes and EPL risk, adjusted binary logistic regression models were employed.

The mean age of the participants was 28.5 years, and their mean BMI was 24.20 kg/m². The dietary intake of carbohydrates, dietary fiber, monounsaturated fatty acids, omega-3 fatty acids, folate, vitamin C, potassium, iodine and total minerals were statistically higher in the control group (p < 0.05). Dietary vitamin D and cholesterol intake and the omega-6/omega-3 ratio were greater in the case group without statistical significance (p > 0.05). The control group presented significantly higher proportions of dietary supplement use, regular consumption between meals, and higher daily meal number (p < 0.05). Adjusted binary logistic regression analysis revealed negative correlations between total dietary fiber intake (continuous and Q3/Q4) and EPL risk in all models, even after adjusting for all potential confounders (p < 0.05). There was no statistically difference regarding nutrition knowledge level between two groups (p > 0.05).

This study contributes to the literature by showing the protective role of maternal nutritional status in the first trimester against EPL risk.