Open AccessEclampsia is more prevalent during the winter season in Sweden
Author(s) -
RYLANDER ÅSA,
LINDQVIST PELLE G.
Publication year - 2011
Publication title -
acta obstetricia et gynecologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.401
H-Index - 102
eISSN - 1600-0412
pISSN - 0001-6349
DOI - 10.1111/j.1600-0412.2010.01010.x
Subject(s) - eclampsia , medicine , incidence (geometry) , odds ratio , confidence interval , pregnancy , obstetrics , population , sunlight , demography , environmental health , genetics , physics , astronomy , sociology , optics , biology
Hypertensive pregnancy conditions have shown seasonal variations and have been related to low levels of vitamin D. In Sweden, the hours of sunlight per day are few in winter. We hypothesized that eclampsia would be more common in the winter season. We performed a population‐based cross‐sectional study of all singleton deliveries in Sweden during a 5‐year period ( n = 482,759 women). All parturients with eclampsia were included as cases and those without formed control group. The incidence of eclampsia was nearly doubled during winter season (odds ratio 1.9, 95% confidence interval 1.4–2.6) as compared to other seasons. The incidence of eclampsia during the period studied (1990–1994) was four in 10,000 pregnancies. We found that eclampsia was twice as common in winter and we introduce the alternative hypothesis that lack of sunlight exposure increases women's susceptibility to eclampsia, possibly due to vitamin D insufficiency.