Nutritional aspects of behaviour and biology during pregnancy and postpartum

III Sammanfattning på svenska VII Abbreviations IX Definitions used in the thesis XI Original papers XIII Preface 1 Introduction 2 Swedish antenatal care 3 Dietary recommendations 3 Dietary supplementation 5 Exposures to avoid or reduce 6 Weight gain and obesity 7 Behavioural changes; physical activity and diet 8 Vitamin D physiology and synthesis 9 Vitamin D in relation to pregnancy and after birth 12 Basic regulation of food intake 13 Steroid hormones, neuroactive steroids and allopregnanolone 13 Pregnancy and allopregnanolone 14 Allopregnanolone and food intake 14 The GABA system and allopregnanolone 15 Aims of the thesis 17 Methods 18 Study I 19 Material and methods 19 Participants 19 Interviews 20 Study II-IV 21 Settings 21 Sample size 21 Participants 21 The questionnaires 24 Estimation of dietary intake 24 Blood sampling 25 Participants-study II 25 Participants-study III 27 Participants-study IV 29 Analysis 31 Study I 31 II Statistical analyses study II-IV 34 Study II 34 Study III 34 Study IV 35 Biochemical analyses study III-IV 35 Ethical considerations 36 Ethical reflections 36 Results 38 Study I 38 Study II 40 Study III 41 Study IV 46 Discussion 48 Methodological considerations 54 Study I 55 Study II-IV 57 Conclusions 62 Clinical implications and future research 62 Acknowledgements 64 References 68 Original papers III Abstract Background A well-balanced nutritious diet is important for the pregnant woman and the growing fetus, as well as for their future health. Poor nutrition results from both over-consumption of energy-rich foods which can lead to a higher weight gain than is healthy and under-nutrition of essential nutrients. Food intake is regulated in complex biological systems by many factors, where steroid hormone is one factor involved.