Clinical Evidence Handbook

A Publication of BMJ Publishing Group

Nausea and Vomiting in Early Pregnancy

 


FREE PREVIEW. AAFP members and paid subscribers: Log in to get free access. All others: Purchase online access.


FREE PREVIEW. Purchase online access to read the full version of this article.

Am Fam Physician. 2015 Sep 15;92(6):516-517.

Author disclosure: Mario Festin declares that he has no competing interests.

More than one-half of pregnant women have nausea and vomiting, which typically begins by the fourth week and disappears by the 16th week of pregnancy.

  • The cause of nausea and vomiting in pregnancy is unknown, but it may be due to the rise in human chorionic gonadotropin concentration.

  • In one out of 200 women, the condition progresses to hyperemesis gravidarum, which is characterized by prolonged and severe nausea and vomiting, dehydration, and weight loss.

In general, the trials we found were small and of limited quality. There is a need for other large high-quality trials on this condition with consistent outcomes.

For nausea and vomiting in early pregnancy:

  • Ginger may reduce nausea and vomiting compared with placebo, although studies used different preparations of ginger and reported varying outcome measures.

  • Pyridoxine (vitamin B6) may be more effective than placebo at reducing nausea, but we do not know about vomiting, and evidence was weak.

  • Pyridoxine may be as effective as ginger at reducing nausea and vomiting, although evidence was limited.

  • Acupressure may be more effective than sham acupressure at reducing nausea and vomiting. However, evidence was weak, and interventions and outcomes varied between trials.

  • We do not know if acupressure is more effective than pyridoxine at reducing nausea or vomiting because we found insufficient evidence.

  • We do not know if acupuncture is more effective than sham acupuncture at reducing nausea and vomiting.

  • We do not know if prochlorperazine, promethazine, or metoclopramide reduces nausea or vomiting compared with placebo.

For hyperemesis gravidarum:

  • We do not know if acupressure, acupuncture, corticosteroids, ginger, metoclopramide, or ondansetron is effective at treating hyperemesis gravidarum.

  • Hydrocortisone may be more effective than metoclopramide at reducing vomiting episodes and reducing readmission to the intensive care unit in women with hyperemesis gravidarum.

View/Print Table

Clinical Questions

What are the effects of treatment for nausea and vomiting in early pregnancy?

Likely to be beneficial

Acupressure

Ginger

Pyridoxine (vitamin B6)

Unknown effectiveness

Acupuncture

Metoclopramide

Prochlorperazine

Promethazine

What are the effects of treatments for hyperemesis gravidarum?

Unknown effectiveness

Acupressure

Acupuncture

Corticosteroids

Ginger

Ondansetron

Unlikely to be beneficial

Metoclopramide (less effective than corticosteroids)

Clinical Questions

What are the effects of treatment for nausea and vomiting in early pregnancy?

Likely to be beneficial

Acupressure

Ginger

Pyridoxine (vitamin B6)

Unknown effectiveness

Acupuncture

Metoclopramide

Prochlorperazine

Promethazine

What are the effects of treatments for hyperemesis gravidarum?

Unknown effectiveness

Acupressure

Acupuncture

Corticosteroids

Ginger

Ondansetron

Unlikely to be beneficial

Metoclopramide (less effective than corticosteroids)

Definition

Nausea and vomiting are common problems in early pregnancy. Although often called morning sickness, nausea and vomiting can occur at any time of day and may persist throughout the day. Symptoms usually begin between four and seven weeks' gestation (one study found this to be the case in 70% of affected women), and they disappear by 16 weeks' gestation in about 90% of women. One study found that less than 10% of affected women have nausea, vomiting, or both before the first missed period.

Most women do not require treatment and complete the pregnancy without any special intervention. However, if nausea and vomiting are severe and persistent, the condition can progress to hyperemesis, especially if the woman is unable to maintain adequate hydration, fluid and electrolyte balance, and nutrition. Hyperemesis gravidarum is a diagnosis of exclusion, characterized by prolonged and severe nausea and vomiting, dehydration, and weight loss. Laboratory investigation may show ketosis, hyponatremia, hypokalemia, hypouricemia, metabolic hypochloremic alkalosis, and ketonuria.

Incidence and Prevalence

Nausea affects about 70%, and vomiting about 60%, of pregnant women. The true incidence of hyperemesis gravidarum is unknown. It has been documented to range from three to 20 in 1,000 pregnancies. However, most authors report an incidence of one in 200.

Etiology

The causes of nausea and vomiting in pregnancy are unknown. The theory that they are caused by a rise in human chorionic gonadotropin concentration is compatible with the natural history of the condition, its severity in pregnancies affected by hydatidiform mole, and its good prognosis (see Prognosis). The cause of hyperemesis gravidarum is also uncertain. Endocrine and psychological factors are suspected, but evidence is inconclusive. Female fetal sex has been found to be a clinical indicator of hyperemesis. One prospective study found that Helicobacter pylori infection was more common in pregnant women with hyperemesis gravidarum than in pregnant women without it (95 out of 105 women [91%] with hyperemesis gravidarum had positive H. pylori immunoglobulin G concentrations compared with 60 out of 129 women [47%] without hyperemesis gravidarum). However, it was not clear whether this link was causal.

Prognosis

One systematic review found that nausea and vomiting were associated with a reduced risk of miscarriage (six studies, 14,564 women; odds ratio = 0.36; 95% confidence interval, 0.32 to 0.42) but found no association with perinatal mortality. Hyperemesis gravidarum is thought by some to induce nutrient partitioning in favor of the fetus, which could explain the association with improved outcome in the fetus. Nausea and vomiting and hyperemesis usually improve over the course of pregnancy, but in one cross-sectional observational study, 13% of women reported that nausea and vomiting persisted beyond 20 weeks' gestation. Although death from nausea and vomiting during pregnancy is rare, morbidities, including Wernicke encephalopathy, splenic avulsion, esophageal rupture, pneumothorax, and acute tubular necrosis, have been reported.

search date: September 2013

Adapted with permission from Festin M. Nausea and vomiting in early pregnancy. Clin Evid Handbook. June 2015:490–492. Visit http://www.clinicalevidence.bmj.com for full text and references.

Author disclosure: Mario Festin declares that he has no competing interests.

This is one in a series of chapters excerpted from the Clinical Evidence Handbook, published by the BMJ Publishing Group, London, U.K. The medical information contained herein is the most accurate available at the date of publication. More updated and comprehensive information on this topic may be available in future print editions of the Clinical Evidence Handbook, as well as online at http://www.clinicalevidence.bmj.com (subscription required).

This series is coordinated by Kenny Lin, MD, MPH, Associate Deputy Editor for AFP Online.

A collection of Clinical Evidence Handbook published in AFP is available at http://www.aafp.org/afp/bmj.



 

Want to use this article elsewhere? Get Permissions


More in AFP

More in Pubmed

MOST RECENT ISSUE


Dec 1, 2016

Access the latest issue of American Family Physician

Read the Issue


Email Alerts

Don't miss a single issue. Sign up for the free AFP email table of contents.

Sign Up Now

Navigate this Article