SummaryBackground: The evidence for a relationship between maternal nutritional status during pregnancy and future health of her unborn child is now ample. The different factors that may link fetal development and growth to later health of the fetus are currently gaining increasing attention. Composition of maternal gestational weight gain may be one of the factors that have an impact on this relationship. The purpose of this thesis was to investigate whether maternal intake of energy, macronutrients and fiber during pregnancy had an effect on degree and composition of gestational weight gain and other anthropometric measures in early and late pregnancy.Methods: Pregnant women (N=553) attended a study where body weight and body composition (skinfold thickness) was measured four times during pregnancy and dietary intake was assessed twice using a food frequency questionnaire. Results: Women with a high energy intake increased their body weight more during pregnancy than women with a lower intake of energy (p<0.01). High energy intake was also associated with a higher increase in skinfold thickness (p<0.01). High intake of carbohydrates and added sugar was associated with higher weight gain (p=0.02 and 0.02 respectively). Smaller total skinfold thickness was reported among women with a fiber intake ¡Ý25g/day (p=0.03). Conclusion: In a well nourished population like the present one, the effects of nutrition on degree and composition of gestational weight gain and single anthropometric measures appear overall small. More sophisticated methods should be used to obtain more detailed information about body composition if the relationship is to be further explored. The small effects of maternal energy intake on gestational weight gain and body composition support the data indicating that pregestational nutritional and metabolic status is important for the fetal growth and development. A larger proportion of the study population did not eat according to the Nordic Nutritional Recommendations. Furthermore, a relatively high and increasing proportion of women enter pregnancy overweight or obese. In this case prevention of obesity and overweight in the young female population should get special attention.