Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Call emergency services or go to an emergency department if you faint, become confused, have difficulty walking, vomit a significant amount of blood, have severe chest pain, or develop sudden shortness of breath.
Get immediate help if you have thoughts of harming yourself or do not feel able to stay safe.
Contact your pregnancy care team promptly if vomiting is getting worse, you are losing weight, or you cannot keep down enough food, fluid, or prescribed medicine.
Passing much less urine, having dark urine, or feeling dizzy when standing can indicate dehydration.
Seek urgent same-day care if you:
These are not routine HG symptoms.
Routine follow-up is appropriate when symptoms are stable and you can keep down enough fluid and medicine.
You should still report ongoing weight loss, medicine side effects, worsening mood, or a change in your usual symptoms.
Every sign above is quoted from the sofidex article on Hyperemesis gravidarum. If you are not sure, err upward — it is always reasonable to be checked.