Download PDFPDF
Haemoglobin discordances in twins: due to differences in timing of cord clamping?
Compose Response

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.
Author Information
First or given name, e.g. 'Peter'.
Your last, or family, name, e.g. 'MacMoody'.
Your email address, e.g.
Your role and/or occupation, e.g. 'Orthopedic Surgeon'.
Your organization or institution (if applicable), e.g. 'Royal Free Hospital'.
Statement of Competing Interests


  • A rapid response is a moderated but not peer reviewed online response to a published article in a BMJ journal; it will not receive a DOI and will not be indexed unless it is also republished as a Letter, Correspondence or as other content. Find out more about rapid responses.
  • We intend to post all responses which are approved by the Editor, within 14 days (BMJ Journals) or 24 hours (The BMJ), however timeframes cannot be guaranteed. Responses must comply with our requirements and should contribute substantially to the topic, but it is at our absolute discretion whether we publish a response, and we reserve the right to edit or remove responses before and after publication and also republish some or all in other BMJ publications, including third party local editions in other countries and languages
  • Our requirements are stated in our rapid response terms and conditions and must be read. These include ensuring that: i) you do not include any illustrative content including tables and graphs, ii) you do not include any information that includes specifics about any patients,iii) you do not include any original data, unless it has already been published in a peer reviewed journal and you have included a reference, iv) your response is lawful, not defamatory, original and accurate, v) you declare any competing interests, vi) you understand that your name and other personal details set out in our rapid response terms and conditions will be published with any responses we publish and vii) you understand that once a response is published, we may continue to publish your response and/or edit or remove it in the future.
  • By submitting this rapid response you are agreeing to our terms and conditions for rapid responses and understand that your personal data will be processed in accordance with those terms and our privacy notice.
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.

Vertical Tabs

Other responses

  • Published on:
    RE: Hemoglobin discordances in twins: Still unanswered!!!
    • Lianne Verbeek, Pediatric resident Leiden University Medical Center
    • Other Contributors:
      • Arjan te Pas, Neonatologist
      • Enrico Lopriore, Neonatologist

    We thank dr. Kumar and dr. Yadav for their interest in our study. We hope that by stating ‘delayed cord clamping may not be advisable in second-born MC twins after vaginal birth’, we expressed that gynecologists could consider to deviate from the international guidelines in some cases. It is possible that not all babies will benefit from placental transfusion in a similar way. However, we certainly agree with dr. Kumar and dr. Yadav that the optimal timing of umbilical cord clamping in twins warrants further investigation.

    Conflict of Interest:
    None declared.
  • Published on:
    Hemoglobin discordances in twins: Still unanswered!!!
    • Jogender Kumar, Neonatologist Post Graduate Institute of Medical education and Research, Chandigarh India 160012
    • Other Contributors:
      • Arushi Yadav, Doctor

    We read with great interest the article by Lianne Verbeek et al, published in this journal and found the results impressive however we didn’t agree with the conclusion drawn by the author.[1] In present study authors concluded that delayed cord clamping may not be advisable in second-born monochorionic twins after vaginal birth due to polycythemia and associated complications. We don’t agree with the authors in this regard. In this study there was no difference in symptomatic polycythemia, need for the partial exchange or mortality. There is no mention about hypoglycemia and jaundice in the study population. American heart association guidelines for neonatal resuscitation[2] recommends delayed cord clamping (DCC) for all preterms who didn’t require resuscitation in view of their potential benefits (decreased mortality, higher blood pressure and blood volume, less need for postnatal blood transfusion, less intraventricular hemorrhages and less risk of necrotizing enterocolitis) which outweighs minor possible complications (increased risks of polycythemia and jaundice). We suggest that till there is enough evidence to change practice we should follow DCC for first as well as second order twin in preterm as well as term babies.
    Despite so many studies[1,3,4] on this issue, we are still at the stage of hypothesis only. For better understanding, there is need of large prospective study which keeps a record of the timing of cord clamping to accept/ refute the hypothesis an...

    Show More
    Conflict of Interest:
    None declared.
  • Published on:
    Re: Haemoglobin discordances in twins: is "really" due to differences in timing of cord clamping? A consideration to Verbeek L and co-authors
    • Lianne Verbeek, Dr Department of Pediatrics, Leiden University Medical Center J6-S, Albinusdreef 2, Leiden 2333 ZA, The Netherlands

    We thank Dr. de Carolis and co-authors for their interest in our study on hemoglobin (Hb) level differences at birth in uncomplicated monochorionic and dichorionic twins. We found that second-born monochorionic and dichorionic twins have higher Hb levels at birth compared to first-born twins when delivered vaginally. Since Hb differences at birth are also present in dichorionic twins, we hypothesized that Hb differences might be due to differences in timing of cord clamping, rather than placental vascular anastomoses.

    Several studies demonstrated that delayed cord clamping is associated with higher Hb levels at birth compared to early cord clamping[1], the physiological mechanism is not well understood. Although we agree that other factors may influence Hb levels during delayed cord clamping at birth, the effect of uterine contractions may be not as clear-cut as dr. de Carolis and co-authors suggest. It has been suggested that uterine contractions influence placento-fetal transfusion. However, Westgate et al. found that uterine contractions primarily cause a pressure-induced, differential reduction in flow in both vessels as well as a reduction in uterine flow.[2] This was also observed in lambs, where oxytocin-induced contractions led to a cessation of the umbilical venous flow and the flow in the umbilical artery was greatly reduced resulting in retrograde flow during diastole.[3]

    Reference List

    1. McDonald SJ, Middleton P, Dowswell T, Morris PS: Eff...

    Show More
    Conflict of Interest:
    None declared.
  • Published on:
    Haemoglobin discordances in twins: is "really" due to differences in timing of cord clamping? A consideration to Verbeek L and co-authors

    Dear Editor, We read with interest the article by Verbeek L. et al [1], showing that the second-born twin has higher levels of hemoglobin (Hb) than first-born co-twins after vaginal delivery (VD; Hb differential effect does not occur in twins delivered by Caesarean section. Since Hb difference is present in both uncomplicated monochorionic (MC) and dichorionic (DC) twin pairs, authors focused on the time difference of umbi...

    Show More
    Conflict of Interest:
    None declared.