Behind the Headlines

Monday April 18 2011

There has been a “rise in abortions among mothers denied morning sickness drugs,” reported The Independent. It said that experts have said that “doctors are failing to treat morning sickness … contributing to a three-fold rise in the number of women admitted to hospital with severe nausea and vomiting in the past 20 years”.

The newspaper report is based on a recent article on severe nausea and vomiting in pregnancy. The review, which is the expert opinion of two GPs, discusses the prevalence of severe nausea in pregnancy and how it is currently managed in the UK, drawing comparisons between UK treatment and that in the US and Canada.

This article highlights an important topic and the need for further investigation and discussion of safe and effective treatments for nausea and vomiting in pregnancy. The review used statistics showing that the number of women admitted to hospital with morning sickness has increased over the years. However, it did not show – as might be wrongly concluded from reading the news coverage - that more women are having abortions because of this, or that there is evidence of treatments being withheld. Women should visit their GP for advice on treating morning sickness.

 

Where did the story come from?

The review was written by Roger Gadsby, a GP and associate clinical professor, and Tony Barnie-Adshead, a retired GP, both from Warwickshire. No outside funding was received for the article and both authors declare that they are trustees of a charity called Pregnancy Sickness Support. The article was published in the peer-reviewed medical journal Obstetrics & Gynaecology.

The Independent has covered the story well. However, the newspaper does place too much emphasis on the suggestion that abortion rates are increasing because of this condition. The authors do briefly discuss termination rates in their article, saying that in some cases women may terminate their current pregnancy due to the severity of their morning sickness. However, based on the figures that the authors quote (from 2002 Department of Health abortion statistics), it is difficult to see how the evidence suggests that rates have increased, or that rates are increasing due to drugs being withheld.

 

What was the article about?

This was a narrative review in which experts have drawn on published research to discuss severe nausea and vomiting of pregnancy (NVP) and, specifically, whether it should be treated with drugs. The authors say that severe nausea and vomiting can occur in up to 30% of pregnant women and can cause significant illness. They say that, for some women, the symptoms are so “intolerable that they actually elect to have a termination of the current pregnancy”. They support this statement with Department of Health abortion statistics from 2002. They say these statistics showed that between 1979 and 1992 there were between 25 and 59 legal abortions for “excessive vomiting in pregnancy” in England and Wales, and that between 1992 and 2001 there were between 15 and 37 in England.

Of more prominence in this article were discussions about how common nausea and vomiting are in pregnancy and also how the symptoms are managed for all degrees of severity. The authors go on to discuss Canadian, American and UK clinical guidelines for managing nausea and vomiting in pregnancy, listing these clearly in their text and discussing the differences between the countries.

 

What were the basic results?

The authors quote research that found that about 80% of women have some degree of nausea and vomiting during pregnancy. Between 0.3 and 1.5% have such severe symptoms that they require hospitalisation. Hospitalisations are increasing and in 2006/7 more than 25,000 women were hospitalised for a primary diagnosis of excessive vomiting in pregnancy.

Several systematic reviews into effective treatments for nausea and vomiting have been carried out. The most recent of these found only limited evidence to support the use of drugs such as pyridoxine (vitamin B6), antihistamines and other anti-emetic drugs (drugs to prevent sickness). However, the authors point out that this was in women with mild to moderate nausea and vomiting and that an ongoing review is examining the effects of drugs in women with severe nausea.

The safety of antihistamines in early pregnancy is being studied extensively and a recent review in 200,000 women concluded that there was no link between using H1 blocker antihistamines and major malformations. Antihistamines are the only drug treatment that the National Institute for Health and Clinical Excellence (NICE) recommends for nausea and vomiting in pregnancy. It says that if a woman requests or would like to be considered for treatment for her symptoms then antihistamines should be used.

Another drug, pyridoxine or vitamin B6, has been shown in studies to be effective at reducing symptoms, although the strength of this evidence or the safety of the drug, is not reviewed by these authors. They note that the Cochrane review on the topic (2002) found that pyridoxine reduced nausea. This review has now been withdrawn from the Cochrane Library and replaced with a newer review (2010 – see below) which confirms these findings. The authors say that treatment of nausea should be a high priority and that a cohort study suggests that this treatment is safe for pregnant women.

The authors point out that there are differences between countries in the way that nausea and vomiting is treated. In Canada and the US, early recognition and treatment with a combination of doxylamine (an antihistamine) and pyridoxine are recommended as the first line of treatment. They say that, in the UK, however, the National Institute for Health and Clinical Excellence (NICE) has concluded that “concerns about the possible toxicity of pyridoxine in high doses have not yet been resolved”, and it does not recommend pyridoxine for the treatment of NVP.

 

How did the researchers interpret the results?

The researchers believe that early effective treatment for nausea and vomiting in the UK may reduce hospitalisation rates, as has been seen in other countries. They suggest that the UK should introduce advice that is in line with American and Canadian guidelines. This includes the suggestion that pyridoxine (up to 40mg daily) should be considered as part of the initial, standard treatment for NVP.

They say that women who develop symptoms of nausea and vomiting and who don’t find that lifestyle measures help should be offered a safe and effective oral treatment as soon as they feel that their quality of life is impaired. Pre-emptive treatment as soon as symptoms develop may also be of benefit in women who have had severe nausea and vomiting in prior pregnancies.

 

Conclusion

This is a well written article by two professionals who are summarising the current management of nausea and vomiting in pregnancy in the UK and comparing it to the US and Canada. They highlight differences between clinical recommendations for treatment and, in particular, call for an emphasis on early treatment, even pre-emptive treatment for women with a history of severe nausea and vomiting.

Importantly, this is not a systematic review, and it should be viewed as the personal, although expert, opinions of the authors, supported with some recent evidence. While they clearly summarise the issues of safety and efficacy associated with the different drugs, it is possible that some studies that show a different picture have been missed out as a comprehensive search of the literature did not take place.

When NICE prepared its clinical guidance on antenatal care it carried out a systematic review of all treatments available at the time. On balance, it concluded that issues about toxicity of pyridoxine at high doses have not yet been resolved and so chose not to recommend the drug. This is different to the approach taken by the US and Canada. It is not clear why there are differences.

Although the review quoted statistics that showed that the number of women admitted to hospital with morning sickness has increased over the years, it did not show – as the news coverage suggests it might have - that more women are having abortions because of this or that there is evidence of treatments being withheld.

This is an important article because it brings together a discussion about the prevalence and current treatment of symptoms that can be intolerable for some women in pregnancy. Further research that can identify safe and effective treatments is needed. For more advice on safe treatment for morning sickness, women should visit their GP.

Links to the headlines

Rise in abortions among mothers denied morning sickness drugs. The Independent, April 18 2011

Mothers 'should be given drugs to beat morning sickness'. Daily Mail, April 18 2011

Links to the science

Gadsby, R & Barnie-Adshead, T. (2011). Severe nausea and vomiting of pregnancy: should it be treated with appropriate pharmacotherapy? The Obstetrician & Gynaecologist 2011; 13: 107–11

Further reading

Matthews A, Dowswell T, Haas DM, Doyle M, O'Mathúna DP. Interventions for nausea and vomiting in early pregnancy. Cochrane Database of Systematic Reviews 2010, Issue 9

Antenatal care, NICE 2011

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Analysis by Bazian

Edited by NHS Choices