Original article

Mactier H, Mokaya MM, Farrell L, et al. Arch Dis Child Fetal Neonatal Ed (2011). doi:10.1136/adc.2010.190017 F1 of 4

1Neonatal Unit, Princess Royal Maternity, Glasgow, UK2Human Nutrition Section, Division of Developmental Medicine, Glasgow University, Yorkhill Hospitals, Glasgow G3 8SJ, UK3Department of Vision Sciences, Glasgow Caledonian University, Glasgow, UK

Correspondence to H Mactier, Neonatal Unit, Princess Royal Maternity, 8–16 Alexandra Parade, Glasgow G31 2ER, UK; helen.mactier@ggc.scot.nhs.uk

Accepted 3 November 2010

ABSTRACTBackground Preterm infants have reduced liver

stores of vitamin A at birth compared to term born

infants. Current guidelines recommend an intake of

700–1500 IU/kg/day vitamin A, and there is evidence

to support higher doses for infants with signifi cant lung

disease. The importance of appropriate early nutrition for

preterm infants is increasingly becoming apparent.

Objectives To examine whether preterm infants

admitted to a UK neonatal unit received the currently

recommended amounts of vitamin A during the fi rst

4 weeks of life, and to identify the feeding patterns

associated with optimal vitamin A intake.

Design Retrospective case note review.

Setting UK tertiary neonatal unit.

Population 36 preterm infants with a median gestation

of 30 weeks (range 26–33 weeks) and median birth

weight of 1305 g (range 880–1800 g).

Main outcome measure Mean daily total intake of

vitamin A in each of the fi rst 4 weeks of life.

Results Despite a policy of introducing intravenous lipid

supplemented with fat soluble vitamins on day 2, only

four infants (11%) consistently met the recommended

daily intake of vitamin A during the fi rst 2 weeks of life.

Adequacy of vitamin A intake in the fi rst 2 weeks of life

was not predicted by gestation or pattern of feeding.

Conclusion Recommendations for intravenous vitamin

A supplementation in parenterally fed preterm infants

require revision. Intravenous lipid with added fat soluble

vitamins should be started as soon as possible after

birth, and consideration given to early oral vitamin A

supplementation in those infants tolerant of enteral

feeds.

INTRODUCTIONVitamin A has diverse functions including epi-thelial cell health, immune competency and retinal photoreceptor sensitivity and is of partic-ular importance for developing preterm lungs.1 Ocular reserves of vitamin A regulate both dark adapted retinal function and the health of the corneal epithelium, and may be important in the pathogenesis of retinopathy of prematurity.1

2 Preterm infants are born with low plasma lev-els of vitamin A,3 refl ective of reduced hepatic stores,4 and low plasma levels of vitamin A per-sist throughout the neonatal period in many infants despite intramuscular or intravenous supplementation.5 6

Provision of vitamin A for preterm infants has been the subject of many studies. We know that vitamin A is poorly absorbed when given by the enteral route in the smallest infants, and that intra-venous supplementation is best given in a lipid preparation protected from light.7 Intramuscular

Vitamin A provision for preterm infants: are we meeting current guidelines?H Mactier,1 M M Mokaya,2 L Farrell,3 C A Edwards2

supplementation of vitamin A in extremely low birthweight infants improves respiratory outcome,5 but is not commonly practised in the UK since intramuscular injections are considered too painful to be justifi ed by the relatively mod-est improvement in respiratory outcome. The only intravenous preparation currently available in the UK, Vitlipid N (Fresenius Kabi, Runcorn, UK) provides 920 IU/kg/day vitamin A in the recommended dose of 4 ml/kg/day. Since Vitlipid N is a multivitamin preparation, administering a higher dose of vitamin A will also result in higher doses of the other fat soluble vitamins and is not recommended.

Current guidelines recommend an intake of 700–1500 IU/kg/day vitamin A for preterm infants,8 but suggest that for those preterm infants with signifi cant lung disease, a higher dose of 2000–3000 IU/kg/day may be more appropriate.9 A recent commentary from the European Society for Paediatric Gastroenterology, Hepatology and Nutrition suggests a minimum intake of 1332 IU/kg/day preformed vitamin A in the preterm population, with a maximum recommended dose of 3330 IU/kg/day.10 This is a fairly conservative maximum dose as to date even within carefully controlled clinical trials utilising doses of up to 4300 IU/kg/day, there has been no evidence of acute vitamin A toxicity

What is already known on this topic

▶ Current guidelines recommend a minimum intake of 700–1500 IU/kg/day vitamin A for preterm infants.

▶ Vitamin A may be provided in a variety of ways, including intravenous lipid solution, oral multivitamin supplement or as a constituent of milk.

▶ Compliance with current guidelines is thus diffi cult to assess.

What this study adds

▶ Compliance with guidelines for vitamin A supplementation of preterm infants is poor, particularly in the fi rst 2 weeks of life.

▶ Current vitamin A supplementation of intravenous lipid solutions requires reassessment.

▶ Oral vitamin A supplementation should be considered as soon as the infant is tolerant of enteral feeds.

ADC-FNN Online First, published on January 17, 2011 as 10.1136/adc.2010.190017

Copyright Article author (or their employer) 2011. Produced by BMJ Publishing Group Ltd (& RCPCH) under licence.

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Original article

Mactier H, Mokaya MM, Farrell L, et al. Arch Dis Child Fetal Neonatal Ed (2011). doi:10.1136/adc.2010.190017F2 of 4

of expected enteral feed volume. All infants tolerating enteral feeds are commenced on Dalivit (LPC Medical, Luton, UK) on day 14, at a dose of 0.6 ml once daily. This dose is higher than the manufacturer’s recommended dose for preterm infants, and was chosen after careful consideration, in the knowledge that smaller doses of vitamin A result in low plasma levels of retinol,13 14 and to comply with the recommended intake of 400 IU/day ergocalcipherol.9 15 In the early part of this study, the preferred starting formula in the absence of MEBM was PreNan (Nestlé, Croydon, UK). When this formula ceased to be available, infants were commenced on preterm formula, either Lowbirthweight SMA (LBWSMA; Wyeth Nutrition, Maidenhead, UK) or, latterly, Nutriprem 1 (Nutricia, Trowbridge, UK), providing 306 IU/100 ml or 600 IU/100 ml vitamin A, respectively.

The total amount of both intravenous and enteral feed received by each infant was calculated on a daily basis from feeding and fl uid charts. Similarly, the total amount of vita-min A supplement provided either as Vitlipid N (from exact duration of intravenous lipid infusions) or as Dalivit (from pre-scription charts) was noted. All data were then anonymised and entered into an Excel spreadsheet. The total intake of vitamin A in the week was computed using the manufactur-ers’ nutrient composition tables. It was assumed that MEBM contained approximately 180 IU vitamin A/100 ml.9 16 Breast milk fortifi er added 431 IU vitamin A/100 ml to the MEBM, resulting in an estimated delivery to the infant of 611 IU/100 ml. An average weekly weight for each infant was derived from the measured weight at the midpoint of each week and the mean daily intake of vitamin A for each week (IU/kg/day) was calculated.

RESULTSCase notes were selected for 36 preterm infants to give a spectrum of gestational age, birth weight and severity of ini-tial illness refl ective of practice in a typical tertiary neonatal unit. Gestational ages ranged from 26+2 to 33 weeks (median 30 weeks), with eight infants born at less than 29 weeks gesta-tion. Birth weights ranged from 880 to 1800 g (median 1305 g); 29 infants were appropriately grown and seven weighed less than the 9th centile for gestational age. The majority of infants (31/36, 86.1%) were commenced initially on intrave-nous fl uids with milk feeds gradually introduced during the fi rst week of life. Thirty babies received MEBM, of whom 24 continued to receive MEBM, at least in part, through the fourth week. No baby received donor EBM. All infants who were commenced on intravenous fl uids received intravenous lipid from the second day, and six (17% of the entire cohort) continued to receive intravenous lipid beyond the fi rst week of life. All intravenous lipid contained Vitlipid N in the manu-facturer’s recommended dose. Five babies were exclusively milk fed during the fi rst 4 weeks of life, of whom three (8.3% of the total cohort) received only formula milk. None of these fi ve infants received Vitlipid N. The median gestational age of these latter fi ve infants was 30+4 weeks (range 30+4 to 31+5 weeks) and all were appropriately grown (median birth weight 1730 g, range 1540–1800 g). Three infants remained intoler-ant of enteral feeds after the second week and continued to receive some intravenous lipid; the remaining 33 infants were commenced on Dalivit 0.6 ml daily from day 14.

Average total daily vitamin A intake in the fi rst week ranged from 188 to 921 IU/kg (median 599 IU/kg/day) and was highest in those infants who received intravenous lipid

in this population, nor any evidence of long-term adverse effects.1 5 11 Differing amounts of vitamin A are provided by milk feeds: the vitamin A content of expressed breast milk (EBM) is higher in colostrum and reduces as milk becomes more mature. Standard infant formulae contain amounts of vitamin A comparable to mature breast milk, while newer specialist preterm formulae contain more than three times as much vitamin A as EBM.

There is an increasing awareness of the importance of achieving appropriate nutrition in the early weeks of life, both for long-term health and neurodevelopmental outcome,12 and so it is important to review provision of essential nutrients for preterm infants within our care.

AimThe aim of this audit was to examine provision of vitamin A for a typical preterm population within a tertiary neonatal unit. Specifi cally, we sought to determine whether current recommendations for vitamin A intake are being met and how method of feeding affects provision of vitamin A.

METHODSThis was a retrospective audit of nutrition provided as part of standard care to a group of preterm infants born at or before 33+0 weeks gestation and admitted to the neonatal unit of Princess Royal Maternity, Glasgow. This hospital serves the north and east of Glasgow, delivering approximately 6000 infants per annum. The study was notifi ed to the local hospi-tal research ethics committee; consent was not deemed to be required for an audit of clinical practice.

Local feeding and vitamin supplementation practiceWithin our unit, the majority of extremely preterm infants are commenced on intravenous fl uids on admission, with maternal expressed breast milk (MEBM) introduced as available from day 2, if tolerated. MEBM is either given fresh or frozen for later use; we do not pasteurise mother’s own milk. Pasteurised donor EBM is used occasionally, but only for infants whose mothers cannot express their own milk. Subsequent escala-tion of enteral feeds depends upon overall clinical condition, feed tolerance and availability of MEBM. Larger and more stable infants may be started on full milk feeds on day 1 at a volume of 90 ml/kg, using either MEBM or preterm infant formula. Once full enteral feed volume (at least 150 ml/kg) has been tolerated for at least 48 h, MEBM and/or donor milk is fortifi ed with commercially prepared breast milk fortifi er (Cow and Gate, Trowbridge, UK). When intravenous fl uids are indicated, the starting fl uid is a standard protein 10% glu-cose solution, with an initial infused volume of 90 ml/kg/day. Intravenous lipid solution (Intralipid 20%, Fresenius Kabi) is introduced from day 2 at 1 g/kg/day, increased over the next 2 days if tolerated (as assessed by plasma triglyceride mea-surement) to 3 g/kg/day. Vitlipid N is added to lipid in the manufacturer’s recommended dose of 4 ml/kg/day (providing 920 IU/kg/day of vitamin A); this mixture is prepared under strict aseptic conditions in our pharmacy and infused via coloured tubing to minimise photodegradation of fat soluble vitamins. As milk feeding becomes established, intravenous lipid is gradually reduced (to 2 g/kg/day when 25% of enteral volume is tolerated and to 1 g/kg/day once 50% of enteral vol-ume tolerated), maintaining fat soluble vitamin supplementa-tion by varying the composition of the infused lipid solution. Intravenous lipid is stopped once the infant is tolerating 75%

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Original article

Mactier H, Mokaya MM, Farrell L, et al. Arch Dis Child Fetal Neonatal Ed (2011). doi:10.1136/adc.2010.190017 F3 of 4

(601 vs 326 IU/kg/day). Only nine of the 31 infants who received intravenous lipid in the fi rst week actually received >700 IU kg/day vitamin A. The average daily vitamin A intake during week 1 for the fi ve babies who were exclusively enterally fed ranged from 188 to 707 IU/kg, and was higher (mean 659 IU/kg/day) in the two infants who received exclu-sively Nutriprem 1 formula, compared to the one infant who received LBWSMA alone, or the two infants who received MEBM plus PreNan (average daily intakes 326, 188 and 307 IU/kg, respectively).

Only six infants (17%) achieved an average daily vitamin A intake of ≥700 IU/kg during week 1, and 11 achieved an average daily vitamin A intake of ≥700 IU/kg during week 2. Three of the four infants of birth weight <1000 g received ≥700 IU vitamin A/kg/day during the fi rst week of life, but during week 2 mean daily vitamin A intake for this small cohort ranged from 325 to 629 IU/kg (median 554 IU/kg). Of those eight infants born at <29 weeks gestation, only three received adequate vitamin A during the fi rst week. Only four infants (11% of the total cohort) received on average ≥700 IU vitamin A/ kg/ day during both weeks 1 and 2 of life. Of these four infants, one was exclusively milk fed with Nutriprem 1, two received intravenous lipid plus some MEBM and one received intravenous lipid plus Nutriprem 1. The highest aver-age daily intake of vitamin A during the fi rst 2 weeks of life was 1047 IU/kg achieved in one infant in week 2; no baby received ≥1500 IU vitamin A/kg/day during the fi rst 2 weeks of life. All infants exceeded recommended intake of vitamin A in weeks 3 and 4 with median vitamin A intakes of 4211 and 3697 IU/kg/day, respectively.

The main source of vitamin A in week 1 was Vitlipid N, contributing 61.8% of the total intake (table 1); by week 2 the main source of vitamin A was enteral feeds. Not surprisingly, in weeks 3 and 4, Dalivit was the main source of vitamin A, supplying roughly 80% of the total intake.

DISCUSSIONVitamin A is essential for lung and gut integrity as well as ocu-lar health. Early intramuscular supplementation in extremely low birthweight infants reduces mortality and improves respiratory outcome at 36 weeks postmenstrual age, suggest-ing that adequacy of this nutrient in the fi rst weeks of life may be critical for longer term outcome. In addition to pulmo-nary and hepatic stores of vitamin A, the preterm infant must acquire ocular stores of vitamin A to supply the developing photoreceptors: during the third trimester of pregnancy, the retinal content of rhodopsin (of which vitamin A is an essen-tial component) increases 10-fold.17 There is some evidence

that additional vitamin A may help to reduce the incidence of retinopathy of prematurity; a plausible explanation for this would be protection of the developing photoreceptors.2

This audit has shown considerably lower than recom-mended vitamin A intake in a typical group of preterm infants managed in a tertiary neonatal unit with fairly strict adher-ence to a feeding and vitamin supplementation policy. Despite an active policy of supplying intravenous lipid fortifi ed with fat soluble vitamins according to manufacturer’s guidelines, only 11% of infants consistently achieved the recommended intake of vitamin A during the fi rst 2 weeks of life. Although three out of four infants of birth weight <1000 g received >700 IU/kg/day of vitamin A during the fi rst week, median daily vitamin A intake in week 2 was only 554 IU/kg. No infant came anywhere near achieving the higher vitamin A intake of 2000–3000 IU/kg/day recommended for the smallest and sick-est babies in recent nutritional guidelines.9 10 These data are consistent with a recent study from Norway which showed lower vitamin A intake in the fi rst couple of weeks in very low birthweight infants.16 Provision of intravenous lipid from day 1 is recommended for preterm infants9; since total paren-teral nutrition carries a signifi cant risk of sepsis which can be reduced by ensuring that fl uids are prepared using strict asep-tic techniques, there is however a trade off between adding fat soluble vitamins at ward level and commencing intrave-nous lipids on day 1 or (as is the practice in our unit) awaiting supply of pharmacy-prepared syringes of Intralipid/Vitlipid N mix. Our decision to give a higher dose of Dalivit than recom-mended by the manufacturer is supported by several studies showing that even in more mature preterm infants neither 2500 nor 3000 IU vitamin A/day achieves normal plasma vita-min A levels.16 18 19 Many practising neonatologists will be unaware of the differing amounts of vitamin A in the vari-ous milk formulae, and also unaware of the widely varying amounts of vitamin A in the available multivitamin prepara-tions: Abidec (Chefaro, Huntingdon, UK) contains 1333 IU vitamin A per 0.6 ml, whereas fi ve drops of NHS Healthy Start vitamins provides 776 IU vitamin A.

We have demonstrated that in common with many prac-tices, patients do not always receive medication exactly as prescribed. Intravenous infusions may be temporarily sus-pended, for example to resite cannulae, and intravenous lipid may not be well tolerated, particularly in the sickest infants.9 Within our study population only 9/31 (29%) infants prescribed intravenous lipid in week 1 supplemented with vitamin A at 920 IU/kg/day actually received ≥700 IU vitamin A/kg/day.

Of the four infants who achieved the recommended intake of vitamin A in the fi rst 2 weeks, one was exclusively formula fed with one of the newer specialised preterm infant formulae, and the other three received a mixture of intravenous fl uids and MEBM or infant formula. Thus the adequacy of vitamin A intake cannot easily be predicted.

This study was limited by the small sample size and the use of retrospective data. We cannot exclude inaccurate data entry, although all data were manually checked to ensure no gross errors, and nursing staff compiling the records were very familiar with the documentation process. Staff who compiled the records were unaware that they were to be audited, and so there was no incentive to record feed vol-umes or infusion volumes nearer to those prescribed. Only by using fl uid and feeding charts of actual, rather than pre-scribed, intake can one examine discrepancies between the former and the latter. We assumed that MEBM had a vitamin A content of 180 IU/100 ml; this fi gure is based on accepted

Table 1 Relative contributions of feeds and supplements to total vitamin

A intake in the fi rst 4 weeks of life

Feed/supplement Week 1 Week 2 Week 3 Week 4

Enteral: EBM (%) 12.0 12.4 0.8 0.5Fortifi ed EBM (%) 3 36.6 9 8.3PreNan (%) 10.2 13 0.1 0.3Nutriprem 1 (%) 10.8 21.6 6.9 8.2LBWSMA (%) 2.2 8 1.7 3.2Total (%) 38.2 91.6 18.5 20.8Intravenous: Vitlipid N (%) 61.8 8.4 0.4 0.8Supplement: Dalivit* (%) * * 80.1 78.4

*Dalivit 0.6 ml/day commenced on day 14 if enteral feeds tolerated.EBM, expressed breast milk; LBWSMA, Lowbirthweight SMA.

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Original article

Mactier H, Mokaya MM, Farrell L, et al. Arch Dis Child Fetal Neonatal Ed (2011). doi:10.1136/adc.2010.190017F4 of 4

guidelines, and verifi ed by a recent Scandinavian study16; it would have been more accurate to measure samples individ-ually, but this was not practical. Furthermore, to have done so would not have made these study fi ndings transferable to ‘real life’ practice. Measuring plasma retinol and retinol binding protein levels would have added more information, but the purpose of this study was to examine actual intake of vitamin A relative to recommended levels, rather than suffi ciency of vitamin A.

CONCLUSIONThis study has shown that our current practice of feeding pre-term infants does not meet the recommended intake of vitamin A for this population, even despite signifi cantly increased vita-min A content of newer preterm infant formulae. Intravenous supplementation should begin as soon as safely prepared lipid solutions can be made available, preferably within the fi rst 24 h of life and oral vitamin A should be started as soon as the infant is able to tolerate enteral feeds, with the dose tailored according to the infant’s weight and type of milk feed. There is a need to investigate higher levels of intravenous vitamin A supplementation for those infants unable to tolerate enteral feeds.

Acknowledgements The authors would like to thank the secretarial and medical records staff at Princess Royal Maternity for their assistance in tracking case notes.

Funding Lesley Farrell was supported by the Chief Scientist Offi ce (Scotland): grant CZB/4/316.

Competing interests None.

Contributors HM suggested the review, assisted with analysis of data and wrote the manuscript. MM collected and analysed data and completed the fi rst draft of the manuscript. LF assisted with collection of data. CE contributed to the fi nal manuscript.

Provenance and peer review Not commissioned; externally peer reviewed.

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H Mactier, M M Mokaya, L Farrell and C A Edwards

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