Key messages

•  Untreated HG carries risk of morbidity and mortality for both mother and fetus

• We all share the responsibility for identifying and treating these women

• All guideline-recommended medications are safe in pregnancy on balance of risk and benefit

• There are many unanswered questions regarding the pathophysiology and underlying mechanisms for maternal and fetal consequences

APPENDIX III: Recommended antiemetic therapies and dosages

Recommended antiemetic therapies and dosages

The Management of Nausea and Vomiting in Pregnancy and

Hyperemesis Gravidarum (Green-top Guideline No. 69)

Catherine Nelson-Piercy | Caitlin Dean | Manjeet Shehmar | Roger Gadsby |

Margaret OHara | Kenneth Hodson | Melanie Nana | on behalf of the Royal College of Obstetricians and Gynaecologists

First line

• Doxylamine and Pyridoxine (vitamin B6) 20/20mg PO at night, increase to additional 10/10 mg in morning and 10/10mg at lunchtime if required. Xonvea (licensed in pregnancy, good safety data)

• Cyclizine 50 mg PO, IM or IV 8 hourly

• Prochlorperazine 5-10 mg 6-8 hourly PO (or 3 mg buccal); 12.5 mg 8 hourly IM/IV; 25 mg PR daily

• Promethazine 12.5-25 mg 4-8 hourly PO, IM or IV

• Chlorpromazine 10-25 mg 4-6 hourly PO, IM or IV

Second line

• Metoclopramide 5-10 mg 8 hourly PO, IV/IM/SC (extrapyramidalsx rare, <0.2%) 

• Domperidone 10 mg 8 hourly PO; 30 mg 12 hourly PR

• Ondansetron 4 mg 8 hourly or 8 mg 12 hourly PO; 8 mg over 15 minutes 12 hourly IV; 16 mg daily PR

• (Women taking ondansetron may require laxatives if constipation develops)

Third line

• Hydrocortisone 100 mg twice daily IV and once clinical improvement occurs, convert to prednisolone 40-50 mg daily PO, with the dose gradually tapered (by 5-10 mg per week) until the lowest maintenance dose that controls the symptoms is reached

• (Corticosteroids should be reserved for cases where standard therapies have failed; when initiated they should be prescribed in addition to previously started effective antiemetics. Women taking corticosteroids should have their blood pressure monitored and a screen for diabetes mellitus)

IM intramuscular; IV intravenous; PO by mouth; PR by rectum.

• Nausea & vomiting / morning sickness: Nausea/vomiting in pregnancy (CKS), Morning sickness (NHS Choices), Hyperemesis gravidarum (NHS Choices), Nausea and vomiting in pregnancy (BMJ Best Practice)

Resources

• Seminar May 2024