Diagnosis + Assessment


Nausea and Vomiting in Pregnancy (NVP), and especially Hyperemesis Gravidarum (HG), are incredibly isolating experiences for women. We’ve, thankfully, moved on from the assumption that the condition is psychological and now understand that it is imperative that women receive treatment for their physical suffering. Health care professionals, from all across the care spectrum, serve a vital role in treating women with these conditions - and must take their suffering seriously so they can feel understood and validated.

A small amount of sickness in the early stages of pregnancy is normal but NVP and HG are not to be taken as an unavoidable part of pregnancy. While these conditions remain largely misunderstood women will put up with surprisingly severe symptoms because they assume it’s all par for the course. NVP and HG are not morning sickness and should not be treated as the same by sufferers or their care providers.

At its most basic, NVP and HG require treatment if a woman’s ability to function in her daily life is impacted by her symptoms. If a woman comes to you complaining of constant nausea, frequent vomiting and/or the inability to eat or drink sufficiently you must take these symptoms seriously and start treatment immediately.

Research proves that early intervention decreases the long term severity of the condition, radically reduces the amount of time a woman might spend in hospital (and associated costs) and improves outcomes for both mother and baby.


As with most chronic illnesses there is a spectrum of symptoms that may or may not be present in a woman suffering NVP or HG. Most commonly she will be experiencing one or more of the following:

  • Loss of 5% (or more) of pre-pregnancy weight

  • Dehydration

  • Constipation

  • Nutritional disorders, such as vitamin B1 (thiamine) deficiency, vitamin B6 (pyridoxine) deficiency or vitamin B12 (cobalamin) deficiency

  • Metabolic imbalances such as metabolic ketoacidosis or thyrotoxicosis

  • Headaches or migraines

  • Aversions to food (including the sight or smell)

  • Excessive salivation

  • Exhaustion

  • Low blood pressure

  • Disorientation

  • Dizziness

  • Raised pulse

Symptoms usually begin in the first trimester at about 6-8 weeks gestation, typically peaking at about 9 weeks and settling about 12 weeks for NVP; HG commonly persists until 20 weeks and for some women will continue throughout the pregnancy until delivery.


There are a number of tools useful for diagnosing NVP and HG and it’s severity. We recommend the following:


When diagnosing NVP and HG it is important to rule out other potential causes of nausea and vomiting particularly where symptoms start after the first trimester or where epigastric pain is present. In such cases investigations may be required to rule out other serious conditions such as peptic ulcer, appendicitis, gastro-intestinal obstruct, urinary tract infections.


Ketone analysis has historically been used as a diagnostic criteria and threshold for treatment for HG. Recent systematic reviews have shown the presence of ketones has no correlation to severity of symptoms and is not an indicator of dehydration. Additionally, some pregnant women will have ketones present in their urine throughout pregnancy even when their carbohydrate intake is sufficient. Therefore, in addition to a lack of ketones being a barrier to treatment, ketosis has sometimes been a barrier to discharge in women who have been well enough to go home from the hospital. Based on the best available evidence we do not recommend the use of keto analysis in assessing women with pregnancy sickness or hyperemesis gravidarum.

For more information on why we stand behind the Ditch the Ketones campaign run by Pregnancy Sickness Support, read chairperson Caitlin Dean’s outline here. We also recommend reading the American Journal of Obstetrics and Gynaecology review of ketone use here