Haemoglobin discordances in twins: Due to differences in timing of cord clamping?

Lianne Verbeek, Depeng P Zhao, Johanna M Middeldorp, Dick Oepkes, Stuart B. Hooper, Arjan B te Pas, Enrico Lopriore

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Objective Our objective was to study the differences in haemoglobin (Hb) at birth in dichorionic (DC) versus monochorionic (MC) twins in relation to birth order and mode of delivery. Methods All consecutive DC twin pregnancies and uncomplicated MC twin pregnancies with two live-born twins delivered at our centre were included in this retrospective cohort study. Hb levels at birth and on day 2 were evaluated in association with birth order and mode of delivery. The occurrence of polycythaemia (venous haematocrit >65%) was also recorded. Results A total of 300 DC and 290 MC twin pairs were included. In DC and MC twins delivered vaginally, second-born twins had a higher Hb level at birth compared with their co-twin (mean Hb level 16.7 vs 15.9 g/dL (p<0.01) in DC twins and 17.8 vs 16.1 g/dL (p<0.01) in MC twins). In twins delivered through caesarean section, no intertwin differences in Hb levels were detected. Polycythaemia occurred significantly more often in second-born twins compared with first-born twins delivered vaginally: 10 (5%) vs 2 (1%) (p=0.02) in DC twins and 20 (12%) vs 2 (1%) (p<0.01) in MC twins. Conclusions Second-born DC and MC twins delivered vaginally have higher Hb levels at birth compared with first-born twins. Intertwin Hb differences in MC twins may partly be related to blood transfusion through the vascular anastomoses. Since DC twins do not have anastomoses, other factors may lead to Hb differences, including differences in timing of umbilical cord clamping.

Original languageEnglish
Pages (from-to)F324-F328
Number of pages5
JournalArchives of Disease in Childhood: Fetal and Neonatal Edition
Issue number4
Publication statusPublished - 1 Jul 2017


  • Cord clamping
  • Dichorionic twins
  • Hemoglobin
  • Monochorionic twins
  • Vaginal birth

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