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This is a plain English summary of an original research article. The views expressed are those of the author(s) and reviewer(s) at the time of publication.
Pregnant women could benefit from simple, cheap, “self-help” remedies for mild nausea and vomiting. Ginger, vitamin B6 and possibly acupressure wrist-bands might relieve symptoms for some women, according to a recent overview of research in this area. The review has identified some promising areas for future research.
For sickness that doesn’t respond to “self-help” remedies, prescribed medication like antihistamines or anti-sickness tablets may help. Hospital treatment, including combinations of drugs and intravenous fluids, may be indicated if this doesn’t work.
The review assessed 73 studies that measured how well 33 types of treatment worked for pregnant women experiencing nausea and vomiting. Severity of symptoms could range from simple “morning sickness” to the more severe condition of hyperemesis gravidarum.
The review gives some evidence on treating pregnant women, but it is limited, especially for more severe symptoms. The authors highlight the need for more robust research to compare treatments with costs and clarify the safety of some drugs.
Why was this study needed?
Up to 85% of women experience nausea and vomiting during pregnancy. Usually, symptoms resolve by about 20 weeks of pregnancy and most women can self-manage. However, some women have prolonged, severe vomiting. They may require hospitalisation to treat dehydration, weight loss and electrolyte imbalances that put mother and unborn baby at risk. These severe symptoms, called hyperemesis gravidarum, affect less than one in 100 women.
There are many treatments for sickness in pregnancy. Some women can control symptoms by changing what they eat, others take vitamins and some try alternative therapies such as hypnosis. Doctors can prescribe a number of drugs, though many women would prefer to avoid medication if possible.
This review aimed to assess how well various treatments work for mild to severe nausea and vomiting of pregnancy. They wanted to see how they compare to each other, look at costs, and identify where more research was needed.
What did this study do?
This systematic review identified 64 randomised controlled trials and nine non-randomised comparative studies. Overall, 33 drug and non-drug treatments were included. Most comparisons were to placebo rather than other active treatment.
The main outcome was the severity of symptoms, which was measured using various scales. For example, the Pregnancy-Unique Quantification of Emesis and Nausea (PUQE) with a maximum score of 15. Other outcomes included quality of life, maternal and newborn-baby outcomes, and cost-effectiveness.
The studies were very different from each other, varying in treatments given, symptom severity and how this was recorded. Half of the randomised controlled trials and all comparative studies were judged to be lower quality and at risk of bias. The authors could not combine the results in a formal meta- analysis, and the results should be viewed with some caution.
What did it find?
- Ginger improved nausea and vomiting compared with placebo. This data was limited to treatment of mild symptoms only.
- Two of eighteen trials found acupressure wristbands improved mild symptoms compared with placebo, but the rest did not find any effect or were poorly reported. on of acupuncture was mixed and unclear.
- Vitamin B6 helped women with mild to moderate symptoms and it worked best at higher doses. There was some evidence that vitamin B6 combined with an antihistamine works better than but no better than an anti-sickness tablet (ondansetron). In women with more severe symptoms, pre-emptive treatment before symptoms started was best.
- There was some evidence that antihistamines were more effective than placebo or no treatment in women with mild symptoms.
- The anti-sickness drugs ondansetron and metoclopramide both drugs tended to improve symptoms.
- Two studies found that managing some women with moderate to severe symptoms in the outpatient setting worked as well as admitting them to hospital.
- There was no evidence that any treatments were harmful to women or their babies.
What does current guidance say on this issue?
The Royal College of Gynaecologists and Obstetricians 2016 guidelines advise that women with mild nausea and vomiting are treated in the community.
Anti-sickness medications, such as antihistamines, are advised as the first-choice medication, used in combination if a woman does not respond to one drug. Ondansetron and metoclopramide are thought safe and effective but only advised as second-line medications.
The guidelines say that ginger and acupressure may be used for mild to moderate symptoms. They do not recommend vitamin B6 or hypnotherapy.
For women with more severe symptoms, including those where community treatment has failed, they advise outpatient care if possible, and list specific indications for hospital admission.
What are the implications?
These findings tend to support guideline recommendations to try cheap and simple remedies, such as a ginger or acupressure, as an initial step for mild nausea and vomiting in pregnancy.
However, the evidence is very limited and generally of poor quality. It isn’t clear which drugs work best for severe symptoms that won’t respond to simple measures, as few studies have compared treatments against each other.
There is a need for stronger research into treatments for severe nausea and vomiting in pregnancy to guide NHS treatment. High quality evidence comparing the cost, effectiveness and safety of different drugs would help providers provide better advice on the treatments that do or don’t work.
Citation and Funding
O'Donnell A, McParlin C, Robson SC, et al. Treatments for hyperemesis gravidarum and nausea and vomiting in pregnancy: a systematic review and economic assessment. Health Technol Assess. 2016;20(74):1-268.
This project was funded by the Health Technology Assessment programme of the National Institute for Health Research.
Bibliography
NHS Choices. Vomiting and sickness in pregnancy. London: Department of Health; 2015.
RCOG. The management of nausea and vomiting of pregnancy and hyperemesis gravidarum (Green-top guideline no. 69). London. Royal College of Obstetricians and Gynaecologists; 2016.
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