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. 2024 Dec;103(12):2392-2400.
doi: 10.1111/aogs.14966. Epub 2024 Sep 11.

Risk factors and recurrence of hyperemesis gravidarum: A population-based record linkage cohort study

Sarah Pont  1   2 , Diana M Bond  1   2 , Antonia W Shand  1   2   3 , Iqra Khan  3 , Helga Zoega  4   5 , Natasha Nassar  1   2   6
Affiliations

Risk factors and recurrence of hyperemesis gravidarum: A population-based record linkage cohort study

Sarah Pont et al. Acta Obstet Gynecol Scand. 2024 Dec.

Abstract

Introduction: There are limited contemporary population-based studies on the risk factors for hyperemesis gravidarum (HG), a severe type of nausea and vomiting in pregnancy. This study aimed to determine the prevalence and trend of HG over time, identify risk factors for any and multiple HG health service visits during pregnancy, and investigate HG recurrence across pregnancies.

Material and methods: This population-based record linkage cohort study featured births in New South Wales, Australia from 2010 to 2019. Hospital and emergency data collections were used to identify health service visits for HG using relevant diagnosis codes and were linked to the corresponding pregnancy on the birth data set. Outcomes included any HG and multiple HG visits during pregnancy, and HG recurrence across pregnancies. Annual HG prevalence was calculated, and negative binomial regression was used to examine standardized prevalence trends. Risk factors for any HG and multiple HG visits within a pregnancy were examined using Robust Poisson models with generalized estimating equations and Prentice-Williams-Peterson Gap Time models, respectively. Rates and risk of recurrence were calculated for women with a second and third pregnancy.

Results: Of the 955 107 pregnancies, 21 702 (2.3%) were classified as HG. There was an average annual increase of 6.8% (95% CI 5.3-8.3) in HG prevalence. Younger maternal age, multiple pregnancies, and selected preexisting conditions were associated with an increased risk of HG, with the strongest factor being HG in any previous pregnancy (risk ratio 8.92, 99% CI 8.43-9.44). Hyperemesis gravidarum recurrence at the second (28.9%) and third (54.7%) pregnancies was high.

Conclusions: Hyperemesis gravidarum history is the strongest risk factor for HG, which has implications for counseling and care that women receive around pregnancy.

Keywords: cohort study; epidemiology; hyperemesis gravidarum; pregnancy complications.

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Conflict of interest statement

The authors have no conflicts to declare.

Figures

FIGURE 1
FIGURE 1
Lasagna plots of hyperemesis gravidarum status by pregnancy number, women with first known pregnancy resulting in birth from 2010 to 2017. (A) All women. (B) Women with at least one hyperemesis gravidarum pregnancy. In these plots, color is used to represent the outcome measure (HG status in a particular pregnancy), with each row representing a woman's measurements (HG, no HG, or no pregnancy) over the column variable, which is pregnancy number. Interpretation note: Where pregnancy number 2 is filled in with white space, this represents the women that do not have a second pregnancy on the data.
FIGURE 2
FIGURE 2
Risk of hyperemesis gravidarum by recurrence pattern, women with first known pregnancy resulting in birth from 2010 to 2017. (A) Second pregnancy. (B) Third pregnancy.
FIGURE 3
FIGURE 3
Summary of main findings.
See this image and copyright information in PMC

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