14th July 2006




Morning sickness in pregnant women could be the body’s evolutionary strategy to prevent the woman from eating harmful foods.


New research carried out at the University of Lincoln highlights a strong link between food smells and nausea which supports the theory that women’s bodies are ‘programmed’ to feel sick if they eat potentially harmful food.


Dr Brian Swallow has spent the past five years studying nausea and vomiting in pregnancy (NVP) in women in Hull.


He found that most women (nearly 90 per cent) experience nausea in pregnancy but that fewer than half experience actual vomiting.


A few women experience NVP so severely that they have to be admitted to hospital because they cannot keep any food down. These severe cases are called hyperemesis gravidarum, a condition which affects between one and two per cent of  pregnancies


Other significant findings are that:


·                    women who experience more NVP are often in significantly worse mental

and physical health

·                    women who experience NVP say that smell, and not taste, is the sense that

exacerbates the nausea

·                    the smell of fried or fatty food is the most frequently reported stimulus.


The research study has put paid to a number of myths which have long surrounded ‘morning sickness’. These myths are listed on page two of this press release.


Dr Swallow is now planning to conduct a long-term investigation into hyperemesis gravidarum and to find out more about the impact that odour has on NVP.


Dr swallow is available for interviews until Friday 21st July. To arrange an interview please contact the university press office (details below).



Seven Myths About ‘Morning Sickness’


1          It happens in the morning.

No, it can occur at any time and is as common in the evening as it is in the morning.

2          It happens to everyone.

No, but it depends on how you define pregnancy sickness. Over half of women do not experience vomiting in pregnancy. However, nearly 90 per cent of women experience nausea, with nearly 50% saying they experience it at least once a day.

3          It is something that women just have to put up with.

In terms of medical treatment it is true to say that little is offered to women. However, women can suffer significant social and psychological problems and there is a need for a supportive network to help them through it. There are also some drugs that may help women and some alternative therapies, such as ginger or sea bands, can help in milder cases. Avoiding certain smells can help, especially fried or fatty foods.  Some women report an aversion to the smell of their partners or their children.  Others say that deodorants, cleaning agents and sprays make them worse.

4          It is not a serious problem.

For some women it is. Very severe nausea and vomiting, called hyperemesis gravidarum, used to lead to death. (It is said that Charlotte Brontë died during pregnancy because of this.) Hyperemesis gravidarum is where the woman cannot stop vomiting, even on an empty stomach. It has been described as like the stomach trying to turn itself inside out.  Nowadays women are admitted to hospital to be placed on a saline drip with sometimes the addition of vitamins.

5          It occurs in women who are anxious.

Until fairly recently this was a common myth amongst doctors.  Past research revealed that NVP was related to anxiety, and cause and effect were confused. In actual fact, the NVP caused the anxiety, not the other way round.

6          Hyperemesis gravidarum occurs because the woman is ambivalent towards her unborn baby.

Again, this Freudian explanation was arrived at by interviewing women who were severely sick and discovering, unsurprisingly, that they were not sure that they wanted to carry on with the pregnancy. The ambivalence is caused by the sickness, not the other way round.

7          NVP is harmful to the baby

There is no evidence to support this. Indeed, some research says that women who experience moderate nausea and vomiting have better outcomes – less likelihood of miscarriage and higher birth weight. Women who experience hyperemesis gravidarum may have a higher incidence of low birth weight babies and foetal abnormalities, but so long as women receive appropriate treatment this difference is not significant.


For more information contact: Jez Ashberry, Press and Media Relations Manager

01522 886042             07843 658943             jashberry@lincoln.ac.uk

Visit our news web pages:                              www.lincoln.ac.uk/news/latestnews.htm