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

OBJECTIVE: To investigate whether exposure to hyperemesis gravidarum (HG) is associated with increased maternal long-term mortality. DESIGN: Population-based cohort study. SETTING: Medical Birth Registry of Norway (1967-2002) linked to the Cause of Death Registry. POPULATION: Women in Norway with singleton births in the period 1967-2002, with and without HG. Women were followed until 2009 or death. METHODS: Cox proportional hazard regression model was applied to estimate hazard ratios (HRs) with 95% confidence interval (CI). MAIN OUTCOME MEASURES: The primary outcome was all-cause mortality during follow up. Secondary outcomes were cause-specific mortality (cardiovascular mortality, deaths due to cancer, external causes or mental and behavioural disorders). RESULTS: Of 999 161 women with singleton births, 13 397 (1.3%) experienced HG. During a median follow up of 26 years (25 902 036 person-years), 43 470 women died (4.4%). Women exposed to HG had a lower risk of long-term all-cause mortality compared with women without HG (crude HR 0.82; 95% CI 0.75-0.90). When adjusting for confounders, this reduction was no longer significant (adjusted HR 0.92; 95% CI 0.84-1.01). Women exposed to HG had a similar risk of cardiovascular death as women not exposed (adjusted HR 1.04; 95% CI 0.83-1.29), but a lower long-term risk of death from cancer (adjusted HR 0.86; 95% CI 0.75-0.98). CONCLUSION: In this large population-based cohort study, HG was not associated with an increased risk of long-term all-cause mortality. Women exposed to HG had no increase in mortality due to cardiovascular disease, but had a reduced risk of death from cancer. TWEETABLE ABSTRACT: Population-based cohort study: Hyperemesis was not associated with an increased risk of long-term mortality.

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

OBJECTIVE: To study associations between hyperemesis gravidarum (HG) and birth outcomes. DESIGN: Population-based cohort study. SETTING: Norway. SAMPLE: Singleton births in the Norwegian Birth Registry, 1967-2009 (n = 2 270 363). METHODS: Multiple logistic regression was applied to study associations between HG and dichotomous outcomes; multiple linear regression to study associations between HG, birthweight and gestational length. Generalised estimating equations were applied to obtain valid standard errors. Sub-analysis on data with available information on smoking was conducted (1999-2009). MAIN OUTCOME MEASURES: Small and large for gestational age (SGA/LGA), Apgar score after 5 minutes, very preterm and preterm birth (VPTB/PTB), perinatal death, stillbirth, neonatal death, birthweight and gestational length. RESULTS: No associations between HG and adverse pregnancy outcomes were observed in crude analyses, except for VPTB (odds ratio [OR] 0.79, 95% CI 0.67-0.93). In adjusted analysis, HG was associated with perinatal death (OR 1.27, 95% CI 1.08-1.48). Inverse associations were observed between HG and VPTB (OR 0.80, 95% CI 0.68-0.94) and LGA (OR 0.95, 95% CI 0.90-0.99). Sub-analyses showed no associations between HG and perinatal death (OR 1.29, 95% CI 0.91-1.83). The inverse associations between HG, VPTB and LGA were strengthened (OR 0.66, 95% CI, 0.48-0.91 and OR 0.86, 95% CI 0.79-0.93, respectively). Exposed babies had reduced birthweight and gestational length compared with unexposed, adjusted difference - 21.4 g and - 0.5 days, respectively. Adjustment for smoking slightly strengthened the impact of HG on birthweight. CONCLUSIONS: Inverse associations for HG and VPTB and LGA were observed. HG was associated with slight reductions in birthweight and gestational age.

Is hyperemesis gravidarum associated with placental weight and the placental weight-to-birth weight ratio? A population-based Norwegian cohort study.

INTRODUCTION: Studies have suggested a link between placental weight, placental weight-to-birth weight ratio (PW/BW) and adult health. Hyperemesis gravidarum (HG) may also have implications for adult health. No studies on HG and placental characteristics have been identified. We therefore explored the relationship between HG, placental weight and the PW/BW-ratio in a population-based cohort. METHODS: Singleton births to primiparous women between 1999 and 2009 with data on HG, placental weight and birth weight in the Medical Birth Registry of Norway (MBRN) comprised the study base (n = 200,390). HG was defined through ICD-10 code 021.0, 021.1 and 021.9. Gender and gestational age specific percentile curves for placenta weight and PW/BW ratio were used to define those below the 10th and above the 90th percentile of both outcomes. Associations between HG and dichotomous outcomes were studied by multiple logistic regression. Multiple linear regression was applied to study placental weight as a continuous variable. Male and female offspring were analyzed separately. RESULTS: The prevalence of HG was 1.2%. Women with HG and female offspring had significantly higher risk of a PW/BW-ratio above the 90th percentile (OR = 1.17, 95% CI: 1.03-1.34). HG and PW/BW-ratio below the 10th percentile were inversely associated (OR = 0.70, 95% CI: 0.56-0.89). For male offspring no association was observed for HG and PW/BW-ratio below the 10th or above the 90th percentile. DISCUSSION/CONCLUSIONS: We observed positive associations between HG and high PW/BW ratio limited to female offspring only. The high PW/BW-ratio suggests that there may be a possible link between HG and adult health.