History and exam

Key diagnostic factors

common

first trimester of pregnancy

Typically, NVP begins between the fourth and eighth week after the last menstrual period and resolves in the second trimester.

uncommon

weight loss of >5%

While mild weight loss is common in early pregnancy, >5% weight loss is consistent with hyperemesis gravidarum.[12]

Other diagnostic factors

common

absence of thyroid enlargement/nodules

Thyroid function tests may be abnormal in NVP.[12] The neck should be palpated for the presence of thyroid enlargement or thyroid nodules. A normal examination is supportive of NVP.[2]

uncommon

dry mucous membranes

Suggests hyperemesis gravidarum.[13] Uncomplicated NVP should not present with clinically significant volume depletion.

postural dizziness

Suggests hyperemesis gravidarum.[13] Uncomplicated NVP should not present with clinically significant volume depletion.

tachycardia

Suggests hyperemesis gravidarum.[13] Uncomplicated NVP should not present with clinically significant volume depletion.

hypotension

Suggests hyperemesis gravidarum.[13] Uncomplicated NVP should not present with clinically significant volume depletion.

ketotic breath

Suggestive of significant volume depletion due to hyperemesis gravidarum.

Risk factors

strong

family history of hyperemesis gravidarum

Genetic predisposition seems to play a role in NVP. Studies have demonstrated that both sisters and daughters of women who have had hyperemesis gravidarum have an increased risk of having similar symptoms.[9]

previous history of NVP

Women who have NVP or hyperemesis in one pregnancy are likely to have it again in subsequent pregnancies. Recurrence rates between 15% and 81% have been reported.[2]

Risk of subsequent episodes is associated with severity of previous symptoms.

If symptoms with the first pregnancy are mild, approximately 50% of women report worsening symptoms with subsequent pregnancies.

multiple gestation or increased placental mass

Multiple gestation is associated with an increased incidence of NVP and hyperemesis.[1][10]

gestational trophoblastic disease

Gestational trophoblastic disease is associated with an increased incidence of NVP and hyperemesis.[1]

other causes of increased placental mass

As well as multiple gestation and trophoblastic disease, the incidence of NVP is increased in other conditions that cause increased placental mass (e.g., triploidy, trisomy 21 or trisomy 18, and hydrops fetalis).[1]

weak

female fetus

In one study of pregnant women hospitalized with hyperemesis in the first trimester, the odds of having a female infant was 50% higher compared with healthy pregnant controls (OR 1.5, 95% CI 1.4, 1.7).[11]

history of motion sickness

An association between NVP and a history of motion sickness has been reported.[1]

history of migraine headache

An association between NVP and a history of migraine headache has been reported.[1]

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