Nausea and Vomiting of Pregnancy



Nausea and vomiting begin soon after the first missed period and cease by the fifth month of gestation. Up to three-fourths of women complain of nausea and vomiting during early pregnancy, with the vast majority noting nausea throughout the day. This problem exerts no adverse effects on the pregnancy and does not presage other complications.

Hyperemesis gravidarum is the medical term for severe nausea and vomiting during pregnancy. The symptoms can be severely uncomfortable. You might vomit more than four times a day, become dehydrated, feel constantly dizzy and lightheaded and lose ten pounds or more. Fortunately, there are treatments available, including medicines to prevent nausea. Hyperthyroidism can be associated with hyperemesis gravidarum, so it is advisable to determine thyroid-stimulating hormone (TSH) and free thyroxine (FT4) values in these patients. Of note, these patients will not have a goiter.



The causes of nausea and vomiting of pregnancy and of hyperemesis gravidarum are unknown. However, observational data indicate that these conditions correlate with levels of human chorionic gonadotropin (hCG) and the size of the placental mass, which suggests that placental products may be associated with the presence and severity of nausea and vomiting.

Some women with complete hydatidiform molar pregnancies, in which no fetus is present, have significant nausea and vomiting, which indicates that placental factors, particularly hCG, are responsible. Women with higher hCG levels, such as those with multiple gestations, hydatidiform moles, or fetuses with Down syndrome, are at increased risk of nausea and vomiting.

Symptoms of hyperemesis gravidarum

HG usually starts during the first trimester of pregnancy. Less than half of women with HG experience symptoms their entire pregnancy, notes the HER Foundation.

Some of the most common symptoms of HG are:

  • feeling nearly constant nausea
  • loss of appetite
  • vomiting more than three or four times per day
  • becoming dehydrated
  • feeling light-headed or dizzy
  • losing more than 10 pounds or 5 percent of your body weight due to nausea or vomiting


A. Mild Nausea and Vomiting of Pregnancy

In most instances, only reassurance and dietary advice are required. Because of possible teratogenicity, drugs used during the first half of pregnancy should be restricted to those of major importance to life and health. Vitamin B6 (pyridoxine), 50–100 mg/day orally, is nontoxic and may be helpful in some patients. Pyridoxine alone or in combi­nation with doxylamine (10 mg doxylamine succinate and 10 mg pyridoxine hydrochloride, two tablets at bedtime) is first-line pharmacotherapy. Antiemetics, antihistamines, and antispasmodics are generally unnecessary to treat nausea of pregnancy.

B. Hyperemesis Gravidarum

With more severe nausea and vomiting, it may become necessary to hospitalize the patient. In this case, a private room with limited activity is preferred. It is recom­mended to give nothing by mouth until the patient is improving, and maintain hydration and electrolyte bal­ance by giving appropriate parenteral fluids and vitamin supplements as indicated.

Antiemetics such as prometha­zine (25 mg orally, rectally, or intravenously every 4–6 hours), metoclopramide (10 mg orally or intrave­nously every 6 hours), or ondansetron (4–8 mg orally or intravenously every 8 hours) should be started. Ondanse­tron has been associated in some studies with congenital anomalies. Data are limited, but the risks and benefits of treatment should be addressed with the patient.

Anti­emetics will likely need to be given intravenously initially. Rarely, total parenteral nutrition may become necessary but only if enteral feedings cannot be done. As soon as possible, the patient should be placed on a dry diet con­sisting of six small feedings daily. Antiemetics may be continued orally as needed. After in-patient stabilization, the patient can be maintained at home even if she requires intravenous fluids in addition to her oral intake.

There are conflicting studies regarding the use of corticosteroids for the control of hyperemesis gravidarum, and it has also been associated with fetal anomalies. Therefore, this treatment should be withheld before 10 weeks’ gestation and until more accepted treatments have been exhausted.


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