The use of maternal weight measurements during antenatal care. A national survey of midwifery practice throughout the United Kingdom

The aim of the present study was to examine the use of maternal weight measurements during antenatal care throughout the United Kingdom. A postal questionnaire and follow-up letter were sent to 1500 midwives throughout the United Kingdom, selected at random from the UKCC register. The postal survey achieved a response rate of 44.8% (672/1500 questionnaires), and obtained responses from at least 10 midwives in all but the lowest grade. Respondents were representative of midwives practising throughout the country, in terms of their gender, working hours and grade, although there were fewer midwives in community settings than those in a contemporary representative English sample. The questionnaire obtained information on the background, training and experience of each midwife, together with their attitudes towards antenatal weighing. For those midwives currently involved in antenatal care, additional information was collected on the schedule of antenatal weight measurements, the criteria used to identify ‘abnormal’ weight gain, and the action taken in response to ‘abnormal’ weight gain. 61.8% of the midwives thought that the pattern of maternal weight gain was ‘not important’ in antenatal care, and only 51.5% of those who currently provided antenatal care weighted women at every antenatal visit. However, most midwives (86.1%) cited at least one clinical condition to explain why women are routinely weighed during pregnancy, and over a third of midwives thought that maternal weight gain could detect seven clinical conditions, including obesity, oedema, pre-eclampsia and polyhydramnios. Midwives with more advanced qualifications (degrees and teaching qualifications) and those working in educational or community settings were least likely to believe that weight gain was good at detecting clinical outcomes. Differences in the perceived utility of antenatal weighing influenced whether midwives would act in response to ‘abnormal’ maternal weight gain, and whether they advised women to gain or lose weight during pregnancy. However, the criteria that midwives used for identifying ‘abnormal’ weight gain were variable, and often inappropriate, so that different midwives are unlikely to intervene consistently or to give consistent advice on the basis of maternal weight gain. These differences in practice may lead to extensive and inappropriate variation in antenatal care. Clear guidelines are urgently required to ensure that, if maternal weight measurements are collected during antenatal care, they are collected and used consistently.