Nausea, vomiting of pregnancy and hyperemesis gravidarum

She is 9 weeks, on her fourth presentation in three weeks, and she apologises as you walk in. She has lost 6 kg. She has vomited in the corridor. Someone has already told her that morning sickness is normal. This topic exists because that sentence — repeated across a whole pregnancy — is how wanted pregnancies get ended.^[16][17]

Overview and definition

Nausea and vomiting of pregnancy is the symptom; hyperemesis gravidarum is the disease at the severe end of the same spectrum. Both start early, and the onset date is the diagnostic hinge.^[1][6]

• NVP — nausea and/or vomiting with onset before 16 weeks and no other cause. It affects up to around 70% of pregnancies, so it is the background against which you look for the outlier.^[1][6]
• Hyperemesis gravidarum — reported in roughly 0.3 to 10.8% of pregnancies depending on the definition used, and one of the commonest reasons a woman is admitted to hospital in the first half of pregnancy.^[1][6]
• "Morning sickness" is both wrong and resented: symptoms occur before and after noon, and the phrase trivialises a condition that ends careers, relationships and pregnancies. Do not use it in the station or the clinic.^[1]

Notice what is absent from Windsor: a weight-loss percentage, an electrolyte value, and a ketone reading. That absence is deliberate, and it is examinable.^[3][1]

References21ShowHide

1. [1]Nelson-Piercy C, Dean C, Shehmar M, et al. The Management of Nausea and Vomiting in Pregnancy and Hyperemesis Gravidarum (Green-top Guideline No. 69). BJOG, 2024.PMID 38311315
2. [2]Committee on Practice Bulletins-Obstetrics ACOG Practice Bulletin No. 189: Nausea And Vomiting Of Pregnancy. Obstet Gynecol, 2018.PMID 29266076
3. [3]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.PMID 34555550
4. [4]Koren G, Piwko C, Ahn E, et al. Validation studies of the Pregnancy Unique-Quantification of Emesis (PUQE) scores. J Obstet Gynaecol, 2005.PMID 16147725
5. [5]Ebrahimi N, Maltepe C, Bournissen FG, et al. Nausea and vomiting of pregnancy: using the 24-hour Pregnancy-Unique Quantification of Emesis (PUQE-24) scale. J Obstet Gynaecol Can, 2009.PMID 19941704
6. [6]Fejzo MS, Trovik J, Grooten IJ, et al. Nausea and vomiting of pregnancy and hyperemesis gravidarum. Nat Rev Dis Primers, 2019.PMID 31515515
7. [7]Fejzo M, Rocha N, Cimino I, et al. GDF15 linked to maternal risk of nausea and vomiting during pregnancy. Nature, 2024.PMID 38092039
8. [8]Boelig RC, Barton SJ, Saccone G, et al. Interventions for treating hyperemesis gravidarum. Cochrane Database Syst Rev, 2016.PMID 27168518
9. [9]Nelson-Piercy C, Fayers P, de Swiet M, et al. Randomised, double-blind, placebo-controlled trial of corticosteroids for the treatment of hyperemesis gravidarum. BJOG, 2001.PMID 11213010
10. [10]Huybrechts KF, Hernández-Díaz S, Straub L, et al. Association of Maternal First-Trimester Ondansetron Use With Cardiac Malformations and Oral Clefts in Offspring. JAMA, 2018.PMID 30561479
11. [11]Huybrechts KF, Hernandez-Diaz S, Straub L, et al. Intravenous Ondansetron in Pregnancy and Risk of Congenital Malformations. JAMA, 2020.PMID 31730152
12. [12]Oudman E, Wijnia JW, Oey M, et al. Wernicke's encephalopathy in hyperemesis gravidarum: A systematic review. Eur J Obstet Gynecol Reprod Biol, 2019.PMID 30889425
13. [13]da Silva JSV, Seres DS, Sabino K, et al. ASPEN Consensus Recommendations for Refeeding Syndrome. Nutr Clin Pract, 2020.PMID 32115791
14. [14]Fiaschi L, Nelson-Piercy C, Tata LJ, et al. Hospital admission for hyperemesis gravidarum: a nationwide study of occurrence, reoccurrence and risk factors among 8.2 million pregnancies. Hum Reprod, 2016.PMID 27251205
15. [15]Dean CR, Bruin CM, O'Hara ME, et al. The chance of recurrence of hyperemesis gravidarum: A systematic review. Eur J Obstet Gynecol Reprod Biol X, 2020.PMID 32021976
16. [16]Nana M, Tydeman F, Bevan G, et al. Termination of wanted pregnancy and suicidal ideation in hyperemesis gravidarum: A mixed methods study. Obstet Med, 2022.PMID 36262812
17. [17]Poursharif B, Korst LM, Macgibbon KW, et al. Elective pregnancy termination in a large cohort of women with hyperemesis gravidarum. Contraception, 2007.PMID 18061703
18. [18]Nijsten K, Dean C, van der Minnen LM, et al. Recurrence, postponing pregnancy, and termination rates after hyperemesis gravidarum: Follow up of the MOTHER study. Acta Obstet Gynecol Scand, 2021.PMID 34033123
19. [19]Pont S, Bond DM, Shand AW, et al. Long-term health, neurodevelopmental, and educational outcomes of children born to mothers with hyperemesis gravidarum: a population-based sibling-design record linkage cohort study. Am J Obstet Gynecol, 2025.PMID 40064411
20. [20]Jansen LAW, Shaw V, Grooten IJ, et al. Diagnosis and treatment of hyperemesis gravidarum. CMAJ, 2024.PMID 38621783
21. [21]Foessleitner P, Rager L, Mikula F, et al. The Role of hCG and Histamine in Emesis Gravidarum and Use of a Chewing Gum Containing Vitamin C as a Treatment Option: A Double-Blinded, Randomized, Controlled Trial. J Clin Med, 2024.PMID 39274311