RESEARCH ARTICLE Hyperemesis gravidarum a

is available at the end of the articleBackground Hyperemesis gravidarum is characterized by severe nausea and vomiting during early pregnancy resulting in maternal weight loss, nutritional deficiencies and hospital admis-sions [1]. Little is known of the underlying causes and consequences of the condition. Genetic, hormonal as well as environmental factors are believed to play important roles [2]. Previous research has primarily focused on short-term outcomes associated with hyperemesis, with inconsistent associations demonstrated for preterm birth, low birth weight and risk of offspring small for gestational age [3]. Two recent, large studies based on Norwegian registry data, demonstrated no clinically significant impact of hyperemesis on birth outcomes [4-6]. However, individ-ual studies have reported that hyperemesis may have a long-term impact on disease patterns later in life, includ