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Wait a minute? An observational cohort study comparing iron stores in healthy Swedish infants at 4 months of age after 10-, 60- and 180-second umbilical cord clamping
  1. Ulrica Askelöf1,2,
  2. Ola Andersson3,
  3. Magnus Domellöf4,
  4. Anders Fasth2,5,
  5. Boubou Hallberg6,
  6. Lena Hellström-Westas3,
  7. Karin Pettersson1,2,
  8. Magnus Westgren1,2,
  9. Ingela E Wiklund7,
  10. Cecilia Götherström1,2,8
  1. 1 Department of Clinical Science, Intervention and Technology, Division of Obstetrics and Gynecology, Karolinska Institutet, Stockholm, Sweden
  2. 2 The Swedish National Umbilical Cord Blood Bank, Sahlgrenska University Hospital, Gothenburg, Sweden
  3. 3 Department of Women’s and Children’s Health, Uppsala University, Uppsala, Sweden
  4. 4 Department of Clinical Sciences, Unit for Pediatrics, Umeå University, Umeå, Sweden
  5. 5 Department of Pediatrics, Institution of Clinical Sciences, University of Gothenburg, Gothenburg, Sweden
  6. 6 Department of Neonatology, CLINTEC, Karolinska Institutet and University Hospital, Stockholm, Sweden
  7. 7 Department of Clinical Sciences, Danderyd Hospital, Stockholm, Sweden
  8. 8 Center for Hematology and Regenerative Medicine, Karolinska Institutet, Stockholm, Sweden
  1. Correspondence to Dr Cecilia Götherström; cecilia.gotherstrom{at}


Background and objective Umbilical cord blood (UCB) is a valuable stem cell source used for transplantation. Immediate umbilical cord (UC) clamping is widely practised, but delayed UC clamping is increasingly advocated to reduce possible infant anaemia. The aim of this study was to investigate an intermediate UC clamping time point and to evaluate iron status at the age of 4 months in infants who had the UC clamped after 60 s and compare the results with immediate and late UC clamping.

Design Prospective observational study with two historical controls.

Setting A university hospital in Stockholm, Sweden, and a county hospital in Halland, Sweden.

Methods Iron status was assessed at 4 months in 200 prospectively recruited term infants whose UC was clamped 60 s after birth. The newborn baby was held below the uterine level for the first 30 s before placing the infant on the mother’s abdomen for additional 30 s. The results were compared with data from a previously conducted randomised controlled trial including infants subjected to UC clamping at ≤10 s (n=200) or ≥180 s (n=200) after delivery.

Results After adjustment for age differences at the time of follow-up, serum ferritin concentrations were 77, 103 and 114 µg/L in the 10, 60 and 180 s groups, respectively. The adjusted ferritin concentration was significantly higher in the 60 s group compared with the 10 s group (P=0.002), while the difference between the 60 and 180 s groups was not significant (P=0.29).

Conclusion In this study of healthy term infants, 60 s UC clamping with 30 s lowering of the baby below the uterine level resulted in higher serum ferritin concentrations at 4 months compared with 10 s UC clamping. The results suggest that delaying the UC clamping for 60 s reduces the risk for iron deficiency.

Trial registration number NCT01245296.

  • paediatrics
  • umbilical cord clamping
  • iron deficiency
  • fetal medicine

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  • Contributors CG conceptualised and designed the study, analysed data, critically revised and approved the final manuscript as submitted. UA conceptualised and designed the study, carried out all data collection in the prospective cohort, carried out all analyses, drafted the initial manuscript and approved the final manuscript as submitted. OA designed the data collection instruments, contributed to the study design and provided data for the historical cohorts. He also carried out the initial analyses, critically reviewed and revised the manuscript, and approved the final manuscript as submitted. MD, AF, LH-W, MW, KP, IEW and BH participated in the study design, reviewed and revised the manuscript, and approved the final manuscript as submitted.

  • Funding The prospective part of the study was supported by The Swedish Childhood Cancer Foundation (grant numbers: PROJ11/043, PROJ12/013); the regional agreement on medical training and clinical research (ALF) at Karolinska Institutet (grant number 20140119) and at Sahlgrenska University Hospital and The Dr Åke Olsson Foundation for Hematological Research, Stockholm. The RCT that provided data for the historical cohorts was supported by Regional Scientific Council of Halland; the HASNA Foundation, Halmstad; HRH Crown Princess Lovisa’s Foundation for Child Care, Stockholm; and the Framework of Positive Scientific Culture, Hospital of Halland, Halmstad.

  • Disclaimer The funders were not involved in the study design, data analysis or manuscript preparation.

  • Competing interests None declared.

  • Patient consent Parental/guardian consent obtained.

  • Ethics approval The study was approved by the regional ethical review board in Stockholm (2011/2142-31/3) and the RCT was approved by the regional ethical review board at Lund University (41/2008).

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data sharing statement There are no other unpublished data available from this study.

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