Pre-eclampsia research in the Norwegian Mother and Child Cohort Study

Abstract

Pre-eclampsia is a pregnancy disorder of unknown origin. In Norway, pre-eclampsia is reported in 3 to 4 per cent of registered births. At present, November 2014, a series of investigations into the etiology of preeclampsia have been published internationally from the Norwegian Mother and Child Cohort Study (MoBa), and several studies are ongoing. The intention of this paper is to give a short summary of what has been accomplished, and to discuss future avenues of research concerning causes, mechanisms and consequences of pre-eclampsia. The papers that have been published up to now include seven that concern life-styles (physical activity, tobacco and diet), six that include prior pregnancies, infection, gestational weight gain, toxicants and tryptophan metabolism, and two studies concerning issues of selection and validity. Major findings are that tobacco smoking is only associated with reduced risk of pre-eclampsia when it occurs in the last trimester; that processed food and sugar-sweetened beverages are associated with increased risk while vegetables, vitamin D and probiotics are associated with reduced risk; and that prior induced abortions have the same risk-reducing effect as a prior pregnancy. For future studies, we suggest that better use should be made of the family structure built into MoBa. This includes better use of the discordant pregnancy design. A series of ongoing genetic studies, partly in international consortia, will hopefully open new etiological insights. The indications that pre-eclampsia is related to cardiovascular disease and other complex disorders should be further investigated through systematic follow-up of pre-eclamptic women and controls. Finally, MoBa is eminently suited to study the influences that pre-eclampsia can have on the growing child.