The foundation for this Ph.D. project is the MISA study 2 initiated in 2017 (project period 2017-2033). Overall, the MISA-study examines the effect of nutrition, lifestyle, and environmental pollutants on reproductive factors in Northern Norway and includes clinical examinations of women and newborns, and surveys on clinical practice. This specific Ph.D.-project focuses on iodine status and reproductive health with data from the MISA study and supplied with data from Fit-Futures 3. The aim is to examine iodine status of young women, pregnant women, and breastfeeding women with their newborns and identify risk factors of iodine deficient, and in addition, midwives' and public health nurses' clinical practice regarding iodine. One of the main findings so far is that despite low levels of iodine among young Norwegian women, nurse midwifes, and general practitioners do not focus on iodine status in their clinical practice.