Human Reproduction, Vol. 16, No. 3, 567-573,
March 2001
© 2001 European Society of Human Reproduction and Embryology
Iron metabolism in monochorionic twin pregnancies in relation to twintwin transfusion syndrome
1 University of Manchester, Academic Unit of Obstetrics and Gynaecology, St Mary's Hospital, Manchester, Imperial College School of Medicine, 2 Institute of Obstetrics and Gynaecology, Queen Charlotte's and Hammersmith Hospital, 3 Department of Histopathology, Hammersmith Hospital, and 4 Department of Maternal & Fetal Medicine, Chelsea and Westminster Hospital, London, UK
Fetal iron metabolism was investigated in monochorionic (MC) twin pregnancies in relation to twintwin transfusion syndrome (TTTS). Matched maternal and fetal blood samples were obtained both in utero and at birth from MC twins with TTTS (n = 23) and without TTTS (n = 18). In a second group of 30 twin pairs (15 with and 15 without TTTS), liver iron content was assessed by using archived paraffin wax-embedded blocks. Serum ferritin was determined by radioimmunoassay and values are given as gestation independent Z-scores and expressed as mean with 95% confidence intervals. Ferritin concentrations in the recipients were higher than in the donors both in utero (P < 0.01) and at birth (P < 0.01). Fetal serum ferritin in non-TTTS twins were similar to the recipient twins but higher than the donor twins (P < 0.05). A significant association was found between ferritin concentrations, the total red blood cell count and haemoglobin in the TTTS twin pairs (P < 0.01) and the non-TTTS twins as a group (P < 0.01). The total stainable liver iron was comparable between twin pairs in the TTTS and non-TTTS groups. This study fails to provide evidence of iron overload in the recipient and depletion in the donor twins and, thereby, questions the validity of the conventional theory of inter-twin transfusion as the cause of TTTS.
Key words: chorionicity/ferritin/liver iron/polyhydramnios/twin-twin transfusion syndrome
5 To whom correspondence should be addressed at: St Mary's Hospital, Whitworth Park, Manchester M13 OJH, UK.E-mail: rekha.bajoria{at}man.ac.uk