Nausea and vomiting of pregnancy: Clinical sciences

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Introduction0:00–0:46

Nausea and vomiting of pregnancy is a common condition occurring in the majority of pregnancies. It’s generally referred to as “morning sickness” but can actually occur at any time of the day.
The exact cause is unknown, though it is thought to be due to increased human chorionic gonadotropin, or HCG for short, associated with early pregnancy, as well as the effects of estrogen and progesterone, which relax the lower esophageal sphincter and slow gastric motility.
Nausea and vomiting of pregnancy has a wide spectrum of presentations, from mild symptoms to severe disease and hyperemesis gravidarum, which may even require hospitalization.When assessing a pregnant patient who presents with a chief concern suggesting nausea and vomiting, your first step is to obtain a focused history and physical.

Focused H&P0:46–2:49

Patients typically report nausea, vomiting, malaise, and an inability to tolerate their diet. While obtaining history, pay attention to certain risk factors for nausea and vomiting of pregnancy, such as a history of nausea and vomiting in a prior pregnancy and a family history of nausea and vomiting during pregnancy.
Additionally, you might find other risk factors like a history of migraine headaches, or motion sickness. Nausea and vomiting in pregnancy is also more likely to occur in multiple gestation like twins or triplets, and in a molar pregnancy.
On a physical exam, you may find signs of dehydration, such as decreased skin turgor and dry mucous membranes.Here’s a clinical pearl!
The majority of patients with nausea and vomiting of pregnancy will have symptoms before 9 weeks of gestation. However, if your patient presents with nausea and vomiting for the first time after 9 weeks, or if they have additional signs and symptoms like fever, headache, abnormal neurologic examination, palpable goiter, or severe abdominal pain, then you should look for a more serious underlying condition.Now, back to your patient!
Based on these history and physical exam findings, you can diagnose nausea and vomiting of pregnancy. Your next step is to assess the severity of their symptoms by using a validated scale, such as the Pregnancy-Unique Quantification of Emesis and Nausea, or PUQE.
This scale quantifies the episodes of nausea, vomiting, and retching or dry heaving the patient has per day, and allows you to determine your treatment pathway.
This is especially important as early treatment of nausea and vomiting of pregnancy may help prevent progression to hyperemesis gravidarum.

Mild nausea and vomiting2:49–3:44

Alright, let's talk about the severity of nausea and vomiting, starting with mild symptoms. Pregnant patients with mild nausea and vomiting are generally able to tolerate their diet and continue their daily routines without pharmacologic management.
For these patients, you can start with non-pharmacological treatment like lifestyle modifications. These include dietary changes, such as eating small, frequent meals, incorporating high-protein snacks throughout the day, and avoiding spicy or fatty foods.
Next, you may also recommend switching to an iron-free prenatal vitamin, as iron is associated with worsening nausea and vomiting in pregnancy.
Additionally, you can recommend ginger capsules, as well as acupuncture or acupressure wristbands, which might be beneficial for some patients.
Finally, advise your patients to avoid any triggers that aggravate their symptoms, such as odors, heat, humidity, noise, and flickering lights.Okay, now that treatment for mild nausea and vomiting is complete, let’s talk about moderate symptoms.

Moderate nausea and vomiting3:44–4:48

Patients with moderate nausea and vomiting typically have persistent symptoms that require pharmacological management to help them tolerate their fluid and food intake.
If this is the case, start the treatment with vitamin B6, also known as pyridoxine, alone or along with doxylamine. Now, if the patient has an inadequate response to treatment, meaning their symptoms persist, you can start adding other medications.
For example, you can add either a dopamine antagonist like promethazine; an antihistamine such as diphenhydramine; or a serotonin 5-HT3 inhibitor like ondansetron.
Keep in mind, not all patients respond the same to each medication. One may respond better to an antihistamine, while another may improve on a dopamine antagonist, so don’t be afraid to switch up treatment options if your patient’s symptoms are not well controlled.

Severe nausea and vomiting4:48–7:38

Lastly, now that patients with moderate symptoms are taken care of, let's move on to the patients with severe nausea and vomiting.
These are patients whose symptoms are so severe that they cannot tolerate their fluid and food intake. Additionally, they might present with hypotension, tachycardia, altered mental status, or weight loss and dehydration that require hospitalization and IV hydration.
The next step for the management of severe nausea and vomiting of pregnancy is to perform a workup to rule out other conditions.
This includes labs such as CBC, CMP, amylase, lipase, serum electrolytes, and urinalysis. Additionally, you should obtain a pelvic ultrasound to evaluate for multiple gestation or molar pregnancy.
Now, workup for severe nausea and vomiting of pregnancy typically reveals dehydration and electrolyte imbalances. However, if there are signs of another cause, for example, severely elevated liver enzymes which are concerning for primary hepatitis, then you should switch gears and focus on treating the underlying disease.
Okay, now that we’ve ruled out other conditions, let’s talk about treatment. For patients with severe nausea and vomiting of pregnancy, you can start with pharmacological management right away.
This includes IV hydration, correcting electrolyte deficiencies like hypokalemia and hyponatremia, and thiamine. Medical management includes dopamine antagonists like promethazine or metoclopramide, antihistamines such as diphenhydramine, or a serotonin 5-HT3 inhibitor like ondansetron.
Now, if your patient shows an inadequate response to these treatment measures, you should start thinking about hyperemesis gravidarum.
Hyperemesis gravidarum is the most severe form of nausea and vomiting of pregnancy. It is diagnosed when a patient has persistent vomiting not related to other causes; significant weight loss below their prepregnancy weight; and signs of starvation such as the presence of ketones in their urine.
These patients need continued IV hydration, as well as thiamine, multivitamines, and dextrose. You may also consider enteral tube feeding for nutritional support.
Here is a high-yield fact! Remember that for patients with prolonged vomiting, giving thiamine prior to dextrose is especially important to prevent Wernicke encephalopathy.
Now, if your patient continues to have persistent vomiting after these interventions, it’s time to consider adding a dopamine antagonist like chlorpromazine, or a steroid such as methylprednisolone.
Finally, at this point, you can reconsider enteral nutrition if you didn’t start it before. Alright, as a quick recap… Nausea and vomiting of pregnancy is a common condition.

Review7:38–8:33

Mild symptoms are mostly managed with lifestyle modifications and dietary changes; whereas moderate symptoms require pyridoxine and possibly doxylamine.
If the patient does not respond to these treatments, you can add medications like dopamine antagonists, antihistamines, or serotonin 5-HT3 inhibitors.
Severe symptoms require hospitalization, IV hydration, electrolyte correction, and medications like dopamine antagonists, antihistamines, or serotonin 5-HT3 inhibitors; as well as further workup for other causes.
If the patient doesn’t respond to treatment, they are diagnosed with hyperemesis gravidarum. If this is the case, continue IV hydration and consider enteral tube feeding.
Finally, if they don’t respond, you can add a dopamine antagonist or a steroid to