24th September 2002




Pregnancy sickness is not as common or severe as previously thought, according to new research carried out at the University of Lincoln.


Only 12 per cent of pregnant women vomit either daily or more than once a day, but 50 per cent of women feel like being sick on a daily basis, the research reveals.


The findings are published this month in The Journal of Obstetrics and Gynaecology.


“These findings show an incidence which is considerably less than previous research has identified,” said Brian Swallow from the Department of Psychology at the University of Lincoln, who led the research project.


“However, this does not mean that pregnancy sickness is not a distressing condition. For one group of women there are significant health problems associated with pregnancy sickness. For about one in 100 the condition is so severe that admission to hospital is necessary.”


Researchers asked over 350 pregnant women at the Hull Maternity Hospital to record the severity of their nausea and sickness. “The main aim of the research was to develop a simple questionnaire to help doctors identify more severe cases, known as hyperemesis gravidarum, and to help future research projects,” said Mr Swallow.


“One of the problems is that there have been at least five different methods of measuring nausea and vomiting and of defining hyperemesis gravidarum. This makes it difficult to compare research findings.”


This is the first of a number of studies being conducted by the SOS in Pregnancy Research Group, a collaboration involving the Universities of Lincoln and Hull and the Hull and East Yorkshire NHS Hospital Trust. The group is also looking in more detail at how pregnancy sickness affects the mental and physical health of women and at the effect of smells on sickness.


Their most ambitious project, however, aims to shed more light on the causes and effects of hyperemesis gravidarum. “Women with hyperemesis gravidarum have a miserable pregnancy”, said Mr Swallow. “Although it usually subsides by the 16th week of pregnancy, in nearly a third of cases it continues throughout the pregnancy.”


Researchers still do not know what causes hyperemesis gravidarum. Some say it is a hormonal imbalance, while others suggest psychological or social factors. Others still argue that it is an evolutionary process to prevent women from eating food that may be harmful.


Further details of the research into pregnancy sickness can be obtained from Dr Swallow on 01482 471511 or 01522 886808 or via email on bswallow@lincoln.ac.uk


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

University of Lincoln (tel: 01522 886042)                 email: jashberry@lincoln.ac.uk