Hyperemesis Gravidarum (Excessive Vomiting in Pregnancy)

Hyperemesis Gravidarum Definition

Hyperemesis gravidarum (HEG) is a condition characterized by excessive vomiting and nausea during pregnancy. Although nausea and vomiting are common symptoms of pregnancy, collectively referred to as morning sickness, the intensity of these symptoms are severe and persistent in hyperemesis gravidarum. The term hyperemesis gravidarum literally means excessive (hyper-) vomiting (-emesis) during pregnancy (gravidarum.

Hyperemesis gravidarum is a debilitating disorder during pregnancy that can have severe consequences for both the mother and fetus. In the United States about 5 out of 1,000 pregnant women suffer from hyperemesis gravidarum. This was a significant cause of maternal death in the early 20th century. However, with advances in medical science and nutrition, the mortality rate has reduced.

Hyperemesis Gravidarum Pathophysiology

The pathophysiology behind hyperemesis gravidarum is complex. It involves multiple interactions between biological, psychological and even social factors. The following theories and mechanisms have been proposed as the root cause of hyperemesis gravidarum.

Hormonal changes

Pregnant women undergo hormonal changes, and those suffering from hyperemesis gravidarum have higher than normal levels of Human Chorionic Gonadotrophin (HCG) hormone as would be expected in pregnancy. These excessively high levels of HCG can cause temporary hyperthyroidism (overactive thyroid gland) and also lead to an increase in the estrogen levels. All these factors in turn induce excessive vomiting.

Gastrointestinal dysfunction

Rhythmic gastrointestinal and peristaltic movements are required for appropriate digestion of the food. A disturbance in these movements leads to inadequate digestion, as result of which the body tends to expel the food eaten seen as nausea and vomiting. Thus gastrointestinal dysfunction has a strong link to hyperemesis gravidarum.

Liver dysfunction

About 50% of pregnant women with hyperemesis gravidarum are found to suffer from hepatic dysfunctioning. It is believed that this liver dyfunction hampers the oxidation of fatty acids thereby increasing is concentration in the bloodstream. The fatty acids accumulate in the liver and through various other subsequent effects triggers intense nausea and vomiting.

Stomach infection

Helicobacter pylori is one of the few bacteria that can survive in the stomach and cause an infection. This has been associated with excessive and persistent vomiting and nausea in the pregnant women. Although H.pylori infection does not only occur in pregnant women, it appears that women suffering with hyperemesis gravidarum are more likely to have an H.pylori infection.

Psychological conditions

Psychosocial issues have a profound effect on maternal and fetal health. Disturbances in family life, psychological stress, anxiety and depression can induce excessive vomiting and nausea in pregnant mothers. This is more likely if the mother has other mental health disorders that may have existed prior to pregnancy.

Elevated lipid levels

Some women suffering from hyperemesis gravidarum have high levels of total cholesterol, triglycerides and phospholipids. Also, impaired liver function, as discussed above, may cause the lipid levels to rise beyond the normal levels. This can contribute to the symptoms noted in hyperemesis gravidarum although the exact link is not always clear

Hyperemesis Gravidarum Causes

Human chorionic gonadotropic (HCG)

All pregnant women experience nausea and vomiting of varying degrees of intensity during the first trimester. The placenta releases a hormone known as beta-HCG, which is not normally present. The rapid rise in levels of this hormone in the bloodstream is the reason for vomiting and nausea.

Multiple Fetuses

Another cause that can lead to excessive vomiting is in condition when there are twins, triplets or multiple fetuses. Understandably the level of HCG is much higher in women carrying multiple fetuses and this appears to the be the main contributing factor to hyperemesis gravidarum.

Hydatifom Mole

Hydatidiform mole, which is a rare mass that grows inside the uterus during the early months of pregnancy, is also linked to hyperemesis gravidarum although it does not pose a problem to every pregnant woman.

Family History

A family history of hyperemesis gravidarum is considered as a risk factor. This means that the female relatives, like the mother or sisters of the expectant mother, may have also suffered with hyperemesis gravidarum although an exact genetic link is unclear.

Hyperemesis Gravidarum Symptoms

Early symptoms of hyperemesis gravidarum include :

  • Excessive vomiting
  • Persistent nausea
  • Dehydration
  • Weight loss
  • Lightheadedness
  • Fainting

At later stages, if the symptoms persist or worsen, then other symptoms may become evident, such as :

  • Decreased urination
  • Alternate bouts of constipation and diarrhea
  • Mental confusion
  • Memory loss
  • Dimness of vision
  • Mental apathy
  • Sleeplessness
  • Restlessness
  • Difficulty in walking as a result of muscle weakness and poor coordination
  • Epigastric (upper middle abdominal) pain

Hyperemesis Gravidarum Diagnosis

An initial physical examination may be done in order to check the blood pressure and pulse rate which may be altered with the loss of fluid and electrolytes. Further blood tests like the urea and electrolyte levels will indicate the severity of dehydration. The presence of ketones in urine indicates severe dehydration. An ultrasound test may be performed to check for the presence of hydatidiform mole and the number of fetus. Other investigations will be conducted as is deemed necessary by the gynecologist.

Hyperemesis Gravidarum Complications

Excessive vomiting, along with loss of appetite, leads to dehydration, malnutrition and weight loss. Women suffering from hyperemesis gravidarum who gain less than than 15.4lbs (or 7kgs) in body weight during pregnancy are at risk of giving birth to underweight babies, small for gestational age babies and/or may have preterm delivery.

Due to severe dehydration during hyperemesis gravidarum there may be a sudden drop in blood sugar levels leading to hypoglycemia. Other complications include acute renal failure, hepatitis and peripheral neuropathy. Although uncommon in this day and age, these complications can prove to be fatal if left untreated.

Hyperemesis Gravidarum Treatment

Dietary and lifestyle management should be the first consideration in the treatment if complications have not already arisen.

Eating habits

Small and frequent meals should be consumed and it is advisable for all pregnant women irrespective of hyperemesis gravidarum. This pattern of eating is less likely to lead to gastrointestinal irritation.

Fluids and electrolytes

Consume plenty of fluids to replenish the fluid loss. However, water alone is not sufficient. The salts, known as electrolytes, also need to be replaced and commercially available oral rehydrating solutions (ORS) are preferable.

Vitamins

Vitamin supplements such as vitamin B 6 can be of great help. However, it should be used in moderation within the dosage limits advised by a doctor to prevent vitamin toxicity.

Medication

Medications to counteract nausea and vomiting (anti-emetics) and to increase stomach emptying should only be used when prescribed by a doctor. Overall drugs should be avoided as far as possible so as not to pose a threat to mother and child. In severe cases where there is persistent vomiting and severe dehydration, rehydration may require the administration of intravenous (IV) fluids.

References :

  1. http://www.americanpregnancy.org/pregnancycomplications/hyperemesisgravidarum.html
  2. http://emedicine.medscape.com/article/254751-overview
  3. http://www.nlm.nih.gov/medlineplus/ency/article/001499.htm

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