• Obstetrics and Gynaecology
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Hyperemesis Gravidarum: Causes, Symptoms and Treatment

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  • Revised on: 2020-07-25

Most women during pregnancy experience some kind of morning sickness characterized by nausea and vomiting. When this nausea and vomiting become extreme and uncontrollable resulting in dehydration, weight loss and ketosis its referred to as hyperemesis gravidarum.

The cause of nausea and vomiting in pregnancy is unknown but is believed to result from rapidly increasing levels of estrogens or the β subunit of human chorionic gonadotropin (β-hCG) produced by tissues of the implanting embryo.

This kind of vomiting usually develops between 4-6 weeks of pregnancy reaching its peaks at about 9 weeks of pregnancy and disappears by about 16 or 18 weeks. It usually occurs in the morning (as so-called morning sickness), although it can occur any time of day.

Women with morning sickness continue to gain weight and do not become dehydrated. Therefore hyperemesis gravidarum is an extreme form of normal nausea and vomiting during pregnancy.
Psychologic factors such as anxiety may trigger hyperemesis gravidarum.

How to differentiate between Morning sickness and hyperemesis gravidarum

Morning Sickness:Hyperemesis Gravidarum:
Nausea sometimes accompanied by vomitingNausea accompanied by severe vomiting
Nausea that subsides at 12 weeks or soon afterNausea that does not subside
Vomiting that does not cause severe dehydrationVomiting that causes severe dehydration
Vomiting that allows you to keep some food downVomiting that does not allow you to keep any food down

Who are at risk?

  • Youth
  • Primigravida (mothers  in their first pregnancy)
  • Mothers with eating disorders
  • Mothers with Hydatidiform Mole (Molar pregnancy).

Signs and symptoms

Mothers with HG present with the following features.

  • Inability to keep foods or fluids down
  • loss of body weight
  • Dehydration due to excess fluid loses- loss of skin elasticity
  • Headaches
  • Confusion
  • Hypovolemia and features of hypovolemia such as:
    • Tachycardia
    • Postural hypotension
    • Coma
  • Electrolyte imbalances- Potassium and sodium are lost during vomiting, therefore, leading to hypokalemia and hypovolemia respectively.
  • Features of vitamin B deficiency such as polyneuritis
  • Renal and liver failure may ensue- jaundice
  • A tendency to spit saliva due to ptyalism ( Inability to swallow saliva)
  • Depression

Diagnosis of hyperemesis gravidarum

Hyperemesis gravidarum is suspected from history taking and clinical evaluation of the mother.

If you suspect it. you need to order the following tests such as:

  • PCV, Urea, and electrolytes to guide you in fluid management
  • Liver function tests- There will be elevated aminotransferases and bilirubin
  • Thyroid function tests- There will be marked hyperthyroidism features ie elevated free thyroxine (T4) levels with depressed thyroid-stimulating hormone levels (TSH).
    • This is because thyroxine hormone is converted back to inactive tri-iodothyronine which is inactive so as to slow down the metabolic rate and conserve energy stores.
  • To rule out other causes such as twin pregnancy and hydatidiform mole you will perform an obstetric ultrasound.
  • Urine ketone levels
  • Measure body weight and blood pressure.
  • These tests will help you get the baseline status and also rule out other disorders such as appendicitis, gastroenteritis, cholecystitis, peptic ulcer disease and hyperthyroidism not caused by hyperemesis gravidarum.

Treatment of hyperemesis gravidarum

In some cases, HG can be severe therefore you will be required to admit the mother.

Treatment involves:

  • Temporary holding oral fluid intake followed by gradual resumption of the same.
  • Intravenous fluid treatment to reverse dehydration and restore electrolytes.  Initial treatment is IV fluid resuscitation, beginning with 2 L of Ringer's lactate infused over 3 h to maintain a urine output of > 100 mL/h.
  • If dextrose is given, thiamine 100 mg should be given IV first, to prevent Wernicke's encephalopathy. This does of thiamine should be given daily for 3 days.
  • Administer prophylactic drugs for thromboembolism such as enoxaparin 40mg in 24 hours subcutaneously.
  • Psychological care is needed for these mothers.
  • Antiemetic use. Vomiting that persists after initial fluid and electrolyte replacement is treated with an antiemetic taken as needed;
  • Antiemetics include
    • Vitamin B6 10 to 25 mg po q 8 h or q 6 h
    • Doxylamine 12.5 mg po q 8 h or q 6 h (can be taken in addition to vitamin B6)
    • Promethazine 12.5 to 25 mg po, IM, or rectally q 4 to 8 h
    • Metoclopramide 5 to 10 mg IV or po q 8 h
    • Ondansetron 8 mg po or IM q 12 h
    •  Prochlorperazine 5 to 10 mg po or IM q 3 to 4 h
  • Steroids such as hydrocortisone 100mg twice a day following by prednisone 10-40 mg a day then reduce to 2.5-10mg by 20 weeks gestation.
  • Corticosteroids should be used for < 6 wk and with extreme caution. They should not be used during fetal organogenesis (between 20 and 56 days after fertilization); the use of these drugs during the 1st trimester is weakly associated with facial clefting.
  • If the mothers continue to have persistent vomiting parenteral feeding may be required.

Take note that parenteral feeding has a lot of complications that you will have to weigh between benefits and risks.


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