Chapter 3: Preconception Nutrition: Conditions and Interventions

Obesity characterized by excessive intra-abdominal adiposity contributes to insulin resistance and hormonal dysregulation that impairs fertility, while conversely, severe underweight status and disordered eating patterns create insufficient energy availability that disrupts the endocrine signaling required for ovulation and reproductive function. The chapter addresses polycystic ovary syndrome as a metabolic disorder with profound fertility implications and explores phenylketonuria as a genetic condition requiring lifelong dietary management, with particular emphasis on the critical preconception period where strict adherence to a low-phenylalanine diet for four to six months prior to pregnancy and continuation throughout gestation prevents severe fetal neurodevelopmental damage including microcephaly and intellectual disability through the mechanism of preventing maternal phenylketonuria. For individuals who have undergone bariatric surgery to address obesity, the chapter highlights paradoxical benefits for reducing gestational diabetes and hypertension risk alongside significant risks of micronutrient deficiencies affecting vitamins including B12, D, E, and K as well as essential minerals, requiring careful supplementation protocols and medical monitoring. Celiac disease complicated by intestinal malabsorption and villous atrophy is linked to elevated rates of infertility, pregnancy loss, and intrauterine growth restriction, with adherence to a comprehensive gluten-free diet serving as the primary intervention. The chapter also addresses premenstrual syndrome and its more severe presentation as premenstrual dysphoric disorder, establishing diagnostic criteria while acknowledging insufficient evidence supporting routine vitamin and mineral supplementation for symptom management in these conditions.