Introduction

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Concern over prophylactic administration of vitamin K to newborn babies has continued for almost a decade, following reports in the early 1990s of a statistically significant association between intramuscular vitamin K and childhood cancer.¹ Subsequent studies have, in general, failed to support this association.^2-10 Inconsistencies in results from the United Kingdom in particular have, however, left lingering doubts about the safety of administering vitamin K by the intramuscular route. ^{1 6-10}

Most British studies have had a case-control design, with exposure data collected retrospectively from maternity records. ^{1 6 7 9 10} Details of vitamin K administration may be found in several places in maternity records,⁶ and all studies report that a written record confirming that it has (or has not) been given is often not found. Some research groups have attempted to impute a child's vitamin K status from the hospital policy in place at the time of the child's birth. Vitamin K is, however, unique among drugs given to newborn babiesalthough policies have customarily been decided by paediatricians, a midwife has usually made the final decision to give vitamin K to a healthy baby.

Three assumptions underpin imputation of vitamin K status: that previous policies are accurately recalled by current staff; that policies were followed rigidly; and that vitamin K was often given without a record being made. Anecdotal reports from midwives and paediatricians suggest, however, that official policies were not always followed. If true, this has serious implications for interpreting studies investigating neonatal vitamin K status. Furthermore, continuing controversy over vitamin K is having deleterious effects on babies, parents, midwives, and paediatricians.^11-14

This two phase postal survey of midwives had two aims: to assess the validity of imputing vitamin K status from hospital policy and to investigate the impact of the controversy on current vitamin K polices and midwifery practice in the United Kingdom.

	Methods

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In September 1998 a 10% random sample of midwives registered as practising in the United Kingdom was selected from the professional register by the United Kingdom Central Council for nursing, midwifery, and health visiting. Questionnaires were posted directly to midwives by the central council, and names and addresses were not disclosed to the research team. Midwives could, however, add their names and contact details to the completed questionnaires.

In phase one, all midwives in the sample were sent a questionnaire, a postage-paid return envelope, and a letter describing the study. A freephone telephone number was provided for resolution of queries. The first questionnaire collected, among many other items, data on current vitamin K policies and their implementation. Questionnaires were posted in November 1998, and reminders were sent to non-responders in February and May 1999.

Midwives who returned completed questionnaires, who qualified before 1990 (the year of the first report suggesting a possible link between vitamin K and childhood cancer), and who could be contacted again were eligible for phase two. These midwives were sent an additional questionnaire requesting information on recording practices and whether policies were followed in their earliest jobs (up to four). No reminders were sent to non-responders in phase two.

Questionnaires were checked on receipt, and queries were resolved by discussion with respondents who provided contact information. Data were coded and entered into Microsoft Access databases designed for the study. Analyses were carried out using Access and the statistical software package Stata 6.0 (Stata Corporation, College Station, TX).

	Results

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Response
Of 3191 midwives surveyed, 2515 (79%) replied to phase one and 2294 (72%) completed questionnaires. The age distribution of midwives who completed questionnaires (respondents) closely matched that of all practising midwives on the professional register (statistical analysis of the United Kingdom Central Council's professional registerreports dated July 1998 and November 1999). Distribution of respondents by health region, compared with that of all midwives in post in the NHS at 30 September 1998, is shown in the figure.^15-18

View larger version (30K): [in this window] [in a new window]   Distribution by health region of respondents in phase one (excluding midwives for whom health region not known) and of midwives in post in the NHS at 30 September 1998

Vitamin K policies
Policies in midwives' current jobs (November 1998 to May 1999) are detailed in table 1. Seven distinct policies were described; the most common policy was intramuscular vitamin K for all babies (51.0%; 1159). Overall, in 96.7% (2195) of jobs with an official policy, the policy specifies some form of vitamin K for all babies, if parents consent.

Implementation of current policies
Of the 2271 midwives whose current job had an official policy, 81.8% (1858) reported that the policy was always followed, with 14.3% (326) reporting that it was not and 3.8% (87) being unsure (table 2). The main reason given for not following official policy was parental refusal or insistence on an oral preparation (88.0%; 287), followed by paediatricians (8.0%; 26) and midwives (2.1%; 7) using their own clinical judgment and general practitioners' refusal to prescribe an oral preparation (0.6%; 2).

Implementation of historical policies
Details of 2179 previous jobs (held before 1990) were given in phase two; overall, only 8.5% (185) of these were reported as having no policy on vitamin K. However, midwives were unsure if there had been a policy for an additional 21.7% (473). Although for a minority of these jobs (14.4%) midwives were unable to remember the details of vitamin K administration, for most (85.6%) some details were given but midwives were unsure if it was an official policy.

	Discussion

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This survey of midwives differs from the two previous British surveys of vitamin K prophylaxis in several important ways. In the previous surveys information about vitamin K policies was obtained from postal questionnaires sent to each special care nursery listed by the Neonatal Nurses' Association. No data were collected on births outside these maternity units or on the implementation of policies, and it is not clear who in each unit completed the questionnaire. ^{19 20} The present survey, by asking individual midwives to provide information, has collected data on how policies are interpreted by those who implement them, rather than on how they are interpreted by those who set them.

The response to phase one of this survey was higher than Asch et al reported as the mean for surveys of nurses, the closest comparison group (this survey 79%, Asch et al 61%); the response in phase two (62%) was comparable to the reported mean.²¹ More importantly, the distribution of midwives by health region was broadly similar in both phases to that of all midwives working in the NHS at the time the sample was selected.^15-18

Current vitamin K policies
More than 97% of newborn babies are likely to receive some form of vitamin K routinely, if their parents consent; this is comparable to the 98% reported in a 1993 survey in the British Isles.¹⁹ The downward turn reported in 1993 in the proportion receiving vitamin K intramuscularly does, however, seem to have been reversed, with levels reported here likely to be close to the 57% and 58% figures reported in 1988 and 1982, and higher than the 38% reported in 1993. ^{19 20} It is difficult to assess accurately the proportions receiving vitamin K orally and intramuscularly: numbers receiving it by each route under selective policies, with differing criteria for high risk, are unknown, and 11% of current policies actively encourage parental choice. There is no clear consensus on which babies should receive vitamin K intramuscularly.

Imputation of vitamin K
It is not known whether previous policies are accurately recalled by current staff. It is, however, difficult to feel confident that they always are, given the variety of combinations of criteria for high risk reported for current policies. Only three out of 17 specified criteria are included in more than 50% of selective policies, with additional variation in how some criteria are defined. Although clinical judgment is mentioned as a criterion in only 1.8% of policies, details given by some midwives suggest that it plays a larger partone example is making the distinction between difficult and easy instrumental deliveries. Judging such distinctions would be difficult for those collecting data many years later.