Nausea and Vomiting of Pregnancy and Hyperemesis gravidarum

Nausea and vomiting of pregnancy is a common condition during early pregnancy. Around half of all pregnant women experience vomiting, and more than 80% of women experience nausea in the first 12 weeks. It is often called morning sickness as the symptoms are usually worse in the morning but can occur at any time of the day, and sometimes continue throughout the day.

Nausea and vomiting typically commence around weeks 8 or 9 of pregnancy and subside after 12–14 weeks. However, in 10% of pregnancies symptoms may continue beyond 20 weeks and even until birth.

Nausea and vomiting of pregnancy is not usually causing any adverse effects to developing fetus but can impair the daily routine/ activities of a pregnant woman.

Adequate oral hydration and avoidance of dietary triggers are often sufficient to control the symptoms, but a proportion of women with severe and protracted nausea and vomiting need medical treatment.

Hyperemesis gravidarum: In about .3 to 3 % of pregnant women, severe form of nausea and vomiting can result in to hyperemesis gravidarum (HG). It can lead to dehydration, weight loss and electrolyte imbalance and often requires hospitalization. HG is associated with a higher incidence of low birth babies (LBW), small-for gestational age (SGA) and premature babies.



Symptoms of nausea and vomiting of pregnancy are variable from woman to woman in its severity, such as from decreased appetite to low level nausea and vomiting. Pregnant woman is still able to eat and drink fluids some of the time with these symptoms.

Symptoms are peak at about 9 weeks of pregnancy and diminish as gestation advances; for most women symptoms resolve by the end of first trimester.

In about 0.3 to 3% of pregnant women, the condition may be severe and progresses to hyperemesis gravidarum. Symptoms of hyperemesis gravidarum include-

  • Severe, persistent nausea and vomiting during pregnancy
  •  Increased salivation than normal
  • Weight loss (of more than 5% of pre-pregnancy body weight)
  • Signs of dehydration such as dark urine, weakness, lightheadedness or fainting, dry skin
  • Inability to take in adequate amount of food
  • Constipation


The exact cause of nausea and vomiting during pregnancy is not known. However, it is believed that rapidly rising blood level of human chorionic gonadotropin hormone released by the placenta during pregnancy may cause morning sickness.

Women who have previously suffered from nausea and vomiting in pregnancy are more likely to have symptoms in a subsequent pregnancy.

Mild morning sickness is common. Hyperemesis gravidarum (HG) is less common but more severe. HG can occur in any pregnancy but conditions with increased placental mass such as molar pregnancy and multiple gestations (twins or more babies) are associated with a higher risk for hyperemesis gravidarum.


Medical history, symptoms and physical examination and pregnancy test are sufficient to diagnose nausea and vomiting of pregnancy and hyperemesis gravidarum (HG). Sometimes it is important to rule out other medical reasons for vomiting in a pregnant woman with HG or if nausea and vomiting occur  with following symptoms-

  • Nausea and vomiting that occurs for the first time after 9 weeks of pregnancy                                                               
  • Abdominal pain or tenderness
  • Fever
  • Headache 

Certain diseases such as gastritis, peptic ulcer, hepatitis, cholecystitis, appendicitis, pancreatitis, and migraine may be considered during differential diagnosis for HG.

The following laboratory tests may be done to assess dehydration

  • Complete blood count, hematocrit
  • Serum Electrolytes
  • Urine analysis for  ketones

Pregnancy ultrasound is used to diagnose multiple pregnancy and molar pregnancy.


For nausea and vomiting in pregnancy women may usually not seek help because of concerns about the safety of medications. However, the experts note that treating nausea and vomiting early in pregnancy, before it progresses, can help control symptoms and prevent more serious complications, including hospitalization. Management includes non-pharmacologic therapies and pharmacologic therapies.

Non-pharmacologic therapies-

Sometimes diet and lifestyle changes are sufficient to manage nausea and vomiting of pregnancy. These include-

  • Avoidance of stimuli that provoke nausea and vomiting such as strong odors, heat and noises that trigger the labyrinthine areas
  • Dietary counseling about frequent small meals and avoidance of spicy or fatty foods
  • Use of Ginger (ginger tea made from fresh grated ginger, ginger capsules, and ginger candies)
  • Try bland foods, (such as the BRATT diet -bananas, rice, apple sauce, toast, and tea)
  • Drink fluids often
  • Take a multivitamin that does not contain iron or take folic acid alone in first trimester
  • Eat light food in morning something like dry toast or a plain biscuit before getting up to avoid moving around on an empty stomach

Pharmacologic therapies-

If diet and lifestyle changes do not help to reduce symptoms, or if there is severe nausea and vomiting of pregnancy, medical treatment may be needed. When other medical conditions are ruled out, certain medications can be given by medical expert to treat nausea and vomiting of pregnancy:

  • Vitamin B6 and doxylamine, both drugs taken alone or together have been found to be safe to take during pregnancy and have no harmful effects on the baby.
  • Antiemetic drugs (drugs preventing vomiting): If vitamin B6 and doxylamine combination is not effective, antiemetic drugs may be prescribed by doctor considering the severity of symptoms and safety of drug to use during pregnancy.
  • Women who cannot tolerate oral liquids for a prolonged period or who have clinical signs of dehydration should receive intravenous hydration including dextrose and vitamins. Thiamine should be given before dextrose infusion to prevent Wernicke encephalopathy 


If the condition is not properly managed and sometimes psychological impact prompts some women to consider termination of pregnancy.

Wernicke encephalopathy is caused by vitamin B1 deficiency as a result of persistent vomiting leading to nutrition deprivation and has resulted in permanent neurological disability and death.

Women with hyperemesis gravidarum showed a higher incidence of low birth weight and small for gestational age infants at birth, and premature infants.


Diet and lifestyle changes may help to feel better (due to nausea and vomiting) during early months of pregnancy. These changes are-

  • Eating small portions every 1 to 2 hours and eating and drinking separately can be helpful in preventing nausea vomiting of pregnancy. For example, eat a small portion of food, wait 20 to 30 minutes, then take some liquid.
  • Eat some light food before getting out of bed to avoid moving around on an empty stomach
  • Take a multivitamin that does not contain iron or take folic acid alone in first trimester of pregnancy
  • Avoid smells that provoke nausea and vomiting
  • Drink fluids often
  • Eat bland foods (low in fat and easy to digest such as the BRATT diet- bananas, rice,  apple sauce, toast, and tea)
  • Use of ginger (such as ginger tea made from freshly grated ginger, ginger capsules, and ginger candies)



  • PUBLISHED DATE : Aug 28, 2017
  • CREATED / VALIDATED BY : Dr. Aruna Rastogi
  • LAST UPDATED ON : Nov 27, 2017


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