Table of contents
Nausea and vomiting of pregnancy
What's new
Updated 2024 RCOG guidelines for the diagnosis and management of nausea and vomiting of pregnancy.
Background
Overview
Definition
NVOP, often referred to as morning sickness, is a common condition affecting the majority of pregnancies. It typically presents in the first trimester and is characterized by mild-to-moderate nausea and vomiting. HG is a more severe form of NVOP characterized by excessive, persistent nausea and vomiting leading to dehydration, electrolyte imbalance, weight loss, and hospital admission.
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Pathophysiology
The pathophysiology of NVOP is not fully understood, but it is believed that a combination of hormonal changes, gastric dysrhythmias, and heightened olfactory and gustatory sensitivity may contribute to its development. Pregnancy-related hormones such as progesterone, estrogen, and hCG have been widely studied, and other hormones such as leptin, placental GH, prolactin, thyroid, and adrenal cortical hormones have also been implicated. Additionally, infectious, immunological, psychological, metabolic, and anatomical factors may also play a role in its onset.
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Epidemiology
Nausea during pregnancy is reported in about 50-80% of individuals, with nausea and vomiting occurring in approximately 50%, and HG affecting about 0.3-3% of pregnant individuals.
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Risk factors
Risk factors for NVOP and HG include a history of these conditions in previous pregnancies, multiple pregnancy, and maternal age. Other factors such as obesity, dysmenorrhea, motion sickness, migraine, and a history of psychiatric disorders have also been associated with NVOP and HG.
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Disease course
Clinically, NVOP is characterized by mild-to-moderate nausea and vomiting, typically developing in the first trimester of pregnancy. HG is distinguished by severe nausea and vomiting leading to dehydration, orthostatic symptoms, metabolic and electrolyte imbalance, weight loss, and eventually necessitate hospital admission. Both NVOP and HG can significantly impact the patient's QoL due to persistent symptoms.
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Prognosis and risk of recurrence
The prognosis of NVOP is generally good, with symptoms often resolving with lifestyle and dietary changes, and more severe cases responding to safe and effective treatments. The prognosis of HG is more variable, with some patients experiencing symptoms throughout their pregnancy.
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Guidelines
Key sources
The following summarized guidelines for the evaluation and management of nausea and vomiting of pregnancy are prepared by our editorial team based on guidelines from the American Academy of Family Physicians (AAFP 2024,2023), the Royal College of Obstetricians and Gynaecologists (RCOG 2024), the European Association for the Study of the Liver (EASL 2023), the American College of Gastroenterology (ACG 2016), ...
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Screening and diagnosis
Diagnosis
As per RCOG 2024 guidelines:
Diagnose NVOP when onset is before 16 weeks of gestation and other causes of nausea and vomiting have been excluded.
B
Consider diagnosing HG when symptoms start in early pregnancy and nausea and/or vomiting are severe enough to cause an inability to eat and drink normally and strongly limit daily activities of living. View signs of dehydration as contributory to diagnosis.
C
Classification and risk stratification
Severity assessment: as per RCOG 2024 guidelines, consider using an objective and validated index of nausea and vomiting, such as the PUQE and HyperEmesis Level Prediction tools, to classify the severity of NVOP and HG.
C
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Pregnancy Unique-Quantification of Emesis Score (PUQE score)
In the last 12 hours, for how long have you felt nauseated or sick to your stomach?
Not at all
≤ 1 hour
2-3 hours
4-6 hours
> 6 hours
In the last 12 hours, have you vomited or thrown up?
I did not throw up
1-2
3-4
5-6
≥ 7
In the last 12 hours, how many times have you had retching or dry heaves without bringing anything up?
No time
1-2
3-4
5-6
≥ 7
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Diagnostic investigations
Initial evaluation
As per RCOG 2024 guidelines:
Elicit history, perform a physical examination, and obtain an evaluation for the assessment of NVOP and HG.
B
Obtain ultrasound to confirm viability and gestational age and to assess for multiple pregnancy or trophoblastic disease in patients requiring inpatient care. Consider scheduling this for the next available appointment unless there are other medical reasons for an urgent ultrasound.
E
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Liver tests
Medical management
Setting of care: as per RCOG 2024 guidelines, manage patients with mild NVOP in an outpatient setting with antiemetics.
B
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Antiemetics
Pyridoxine and doxylamine
Thiamine
Corticosteroids
Rehydration therapy
Thromboprophylaxis
Management of constipation
Management of gastroesophageal reflux
Nonpharmacologic interventions
Psychosocial care: as per RCOG 2024 guidelines, assess the severity of the impact of symptoms on the QoL and social situation in patients with NVOP or HG.
B
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Cognitive therapy
Nutritional support
Iron preparations
Ginger
Acupressure
Therapeutic procedures
Patient education
Preventative measures
Follow-up and surveillance
Discharge from hospital
As per RCOG 2024 guidelines:
Discharge patients only when the following are met:
appropriate antiemetic therapy has been tolerated
adequate oral nutrition and hydration have been tolerated
management of concurrent conditions has been completed
E
Advise patients to continue antiemetics where appropriate and ensure they know how to access further care at the time of discharge.
B
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Follow-up