Hyperemesis gravidarum and risks of placental dysfunction disorders: a population‐based cohort study

Abstract

ObjectiveTo study whether pregnancies complicated by hyperemesis gravidarum in the first (<12 weeks) or second (12–21 weeks) trimester are associated with placental dysfunction disorders.DesignPopulation-based cohort study.SettingSweden.PopulationAll pregnancies in the Swedish Medical Birth Register estimated to have started on 1 January 1997 or later and ended in a single birth on 31 December 2009 or earlier (n = 1 156 050).MethodsOdds ratios with 95% confidence intervals were estimated for placental dysfunction disorders in women with an inpatient diagnosis of hyperemesis gravidarum, using women without inpatient diagnosis of hyperemesis gravidarum as reference. Risks were adjusted for maternal age, parity, body mass index, height, smoking, cohabitation with the infant's father, infant's sex, mother's country of birth, education, presence of hyperthyreosis, pregestational diabetes mellitus, chronic hypertension and year of infant birth.Main outcome measuresPlacental dysfunction disorders, i.e. pre-eclampsia, placental abruption, stillbirth and small for gestational age (SGA).ResultsWomen with hyperemesis gravidarum in the first trimester had only a slightly increased risk of pre-eclampsia. Women with hyperemesis gravidarum with first admission in the second trimester had a more than doubled risk of preterm (<37 weeks) pre-eclampsia, a threefold increased risk of placental abruption and a 39% increased risk of an SGA birth (adjusted odds ratios [95% confidence intervals] were: 2.09 [1.38–3.16], 3.07 [1.88–5.00] and 1.39 [1.06–1.83], respectively).ConclusionsThere is an association between hyperemesis gravidarum and placental dysfunction disorders, which is especially strong for women with hyperemesis gravidarum in the second trimester.

Hyperemesis gravidarum and long‐term mortality: a population‐based cohort study

“…Bolin et al 13. reported a doubled risk of pre‐eclampsia and a three‐fold increased risk of placental abruption after HG exposure, suggesting a possible effect on the placentation.…”

“…Based on prior knowledge13, 14, 15, 33 the following covariates were considered as potential confounders: maternal age at first registered pregnancy (continuous), the woman's year of birth (in categories), maternal country of birth, education, parity, hypertensive diseases in pregnancy, placental abruption, pregestational diabetes type 1 and hypertensive disorders before pregnancy.…”

“…Two models were made in addition to the crude analyses: (i) age‐adjusted; (ii) adjusted for all available confounders. The fully adjusted model included all conditions associated with both exposure and outcome as confounders, based on prior knowledge 13, 14, 15, 33. In our population, not all the listed confounders influenced the estimates, but they were included in the fully adjusted model because of the biological aspects.…”

“…Hyperemesis gravidarum (HG), characterised by extreme nausea and vomiting in early pregnancy,12 is associated with gestational hypertension, pre‐eclampsia as well as placental abruption 13. The prevalence of HG varies between 0.3 and 3.2%, depending on the maternal country of birth 14, 15.…”

Hyperemesis gravidarum and birth outcomes—a population‐based cohort study of 2.2 million births in the Norwegian Birth Registry

“…6 A recently published article exploring the risk of placental dysfunction disorders among mothers with HG reported a 39% increased risk of SGA. 7 The largest epidemiological study on HG and pregnancy outcomes until now was based on data from the Swedish Birth Registry, including 3068 women with HG. 8 It reported positive associations between HG and LBW and PTB.…”