The primary aim of the Swedish national population registration system is to obtain data that (1) reflect the composition, relationship and identities of the Swedish population and (2) can be used as the basis for correct decisions and measures by government and other regulatory authorities. For this purpose, Sweden has established two population registers: (1) The Population Register, maintained by the Swedish National Tax Agency ("Folkbokföringsregistret"); and (2) The Total Population Register (TPR) maintained by the government agency Statistics Sweden ("Registret över totalbefolkningen"). The registers contain data on life events including birth, death, name change, marital status, family relationships and migration within Sweden as well as to and from other countries. Updates are transmitted daily from the Tax Agency to the TPR. In this paper we describe the two population registers and analyse their strengths and weaknesses. Virtually 100 % of births and deaths, 95 % of immigrations and 91 % of emigrations are reported to the Population Registers within 30 days and with a higher proportion over time. The over-coverage of the TPR, which is primarily due to underreported emigration data, has been estimated at up to 0.5 % of the Swedish population. Through the personal identity number, assigned to all residents staying at least 1 year in Sweden, data from the TPR can be used for medical research purposes, including family design studies since each individual can be linked to his or her parents, siblings and offspring. The TPR also allows for identification of general population controls, participants in cohort studies, as well as calculation of follow-up time.

Bariatric surgery was associated with reduced risks of gestational diabetes and excessive fetal growth, shorter gestation, an increased risk of small-for-gestational-age infants, and possibly increased mortality. (Funded by the Swedish Research Council and others.).

When a woman requests a cesarean section, both primary fear of birth and traumatic childbirth experiences need to be considered and dealt with. The W-DEQ can be used at any time during pregnancy in order to identify pregnant women who suffer from intense fear of childbirth.

Objective To study the risk of adverse pregnancy outcomes in women with polycystic ovary syndrome, taking into account maternal characteristics and assisted reproductive technology.Design Population based cohort study.