Hyperemesis gravidarum shows minimal impact on offspring school performance

Exposure to hyperemesis gravidarum (HG) during pregnancy has minimal impact on children’s school performance, with no significant difference seen between siblings, according to a recent study published in the American Journal of Obstetrics & Gynecology.¹

HG is a severe form of gestational nausea that occurs in up to 3% of pregnancies and is a common cause of first-trimester hospitalization.² The condition is associated with vomiting, inability to tolerate food or fluids, dehydration, and electrolyte imbalance.¹ Previous studies have examined the maternal consequences of HG, but evidence on long-term effects in offspring has been limited.

“School performance can be considered an indicator of cognitive functioning as well as future education and income. Therefore, we aimed to investigate the school performance of offspring born to mothers with HG compared to nonexposed offspring,” wrote investigators.

Measuring school performance

The nationwide cohort study evaluated the association between maternal HG and school performance in offspring. The investigators included all liveborn children in Denmark from 1986 to 2005 using registry data. Children exposed to HG were identified through maternal diagnoses in the Danish National Patient Registry, and school performance outcomes were obtained from national education registries.

The cohort consisted of 1,162,249 offspring, of whom 1.1% were exposed to HG during pregnancy. Compared with nonexposed children, those exposed were more often female, more frequently born preterm or from multiple pregnancies, and more often born to mothers with lower educational attainment.

The primary outcomes were grade point average (GPA) at completion of ninth grade and a binary measure of low school performance, defined as GPA below 4 or absence of GPA. Secondary outcomes included school failure (GPA <2 or no GPA), high GPA (>10), and special educational needs (SEN) requiring more than 9 hours of assistance weekly. Performance between groups was compared through odds ratios (ORs).

Population-level results

The mean GPA was 6.55 in the HG-exposed group compared with 6.78 in the nonexposed group. After adjustment for confounders, exposure to HG was associated with a slightly lower mean GPA, with an adjusted mean difference of –0.18. Exposed offspring had higher odds of low school performance (adjusted OR, 1.19) and higher odds of school failure (adjusted OR, 1.16). The odds of SEN were also increased (adjusted OR, 1.20). Conversely, exposed offspring were less likely to achieve a high GPA (adjusted OR, 0.83).

To account for familial and genetic confounding, the investigators conducted a within-sibling analysis including 16,235 offspring from 6492 sibling groups. In this analysis, there was no significant difference in GPA between exposed and unexposed siblings (adjusted mean difference, –0.02). Similarly, there were no significant differences in the odds of low school performance, school failure, SEN, or high GPA.

In post hoc analyses limited to severe HG diagnoses coded under ICD-10, the results were consistent with the main findings, though with wider confidence intervals because of fewer cases.

Implications

The authors noted that while HG exposure was associated with slightly lower school performance at the population level, the difference was not clinically meaningful. They concluded that HG during pregnancy is only minimally linked to school performance in exposed offspring.

“Our study addresses a clinically important question and provides much-needed reassurance to affected families and healthcare providers, as HG exposure does not appear to adversely impact school performance,” wrote investigators.

References

1. Fogh MV, Wiingreen R, Ostenfeld A, et al. School performance in offspring born to mothers with hyperemesis gravidarum. Am J Obstet Gynecol. 2025;233:205.e1-12. doi:10.1016/j.ajog.2025.02.041
2. Jansen LAW, Koot MH, Van’t Hooft J, et al. The windsor definition for hyperemesis gravidarum: A multistakeholder international consensus definition. Eur J Obstet Gynecol Reprod Biol. 2021;266:15-22. doi:10.1016/j.ejogrb.2021.09.004