Nausea and Vomiting in Pregnancy

Clinical Notes : Women's Health

Nausea and vomit in pregnancy:(NVP)

also known as morning sickness
50-90% of pregnant women affected
Usual onset 6-8 weeks, peaks at 9 weeks, resolves by 12 weeks
Good news :
- women who experience NVP have been shown to have improved pregnancy outcomes. These include a decrease in miscarriages, pre-term deliveries, and stillbirths.
- In addition, there is a lower prevalence for reduced fetal birth weight, fetal growth restriction, and fetal mortality

Hyperemesis gravidarum is the most severe form
- < 1% of pregnancies.
- Can be associated with twin pregnancies and adverse outcomes
- characterised by persistent vomiting, volume depletion, ketosis, electrolyte disturbances, and weight loss.

Assessment

Review symptoms, hydration, check urine for ketones
In cases of severe nausea and vomiting, esp. if onset is after 12 weeks gestation
- exclude other causes
- take an MSU
- refer back to own GP for further investigation (blood tests and consider a pelvic ultrasound scan/ review by gynae)

Treatment without volume depletion

Treatment without volume depletion but failed conservative management

1st line : pyridoxine and/or doxylamine
- pyridoxine 10-25 mg orally three times daily
2nd line : oral antihistamines or anri-emetics
- primary options
  - Cyclizine (Valoid) 50mg tds
  - Metoclopramide (Maxolon) 5-10 mg orally every 8 hours when required for a maximum of 5 days, maximum 30 mg/day
  - Domperidone (Domerid, Motilium) 10 mg orally three times daily for a maximum of 7 days, maximum 30 mg/day
    - contraindicated in patients with severe hepatic impairment or underlying cardiac disease
    - should not be administered with other drugs that prolong the QT interval or inhibit CYP3A4
- secondary options
- Promethazine (Phenergan): 12.5 to 25 mg orally every 4-6 hours when required
- Chlorpromazine (Clonactil) 10-25 mg orally every 4-6 hours when required
- Prochlorperazine (Stemetil) 5-10 mg orally (immediate-release) every 6-8 hours when required
- Ondansetron (Zofran) 4-8mg tds

Treatment with volume depletion (refer to A+E)

Combination treatment with >1 antiemetic can be used
PPIs or H2 blockers are suggested as an adjunct in women who also have dyspepsia

Criteria for referral to secondary care

Volume depletion
Continued symptoms with ketonuria or >5% loss in body weight, despite oral antiemetics
Continued symptoms and unable to keep down oral antiemetics
Confirmed or suspected comorbidity eg UTI