Twin Research and Human Genetics


Causes of Delivery and Outcomes of Very Preterm Twins Stratified to Zygosity

Juliane Spieglera1 c1, Christoph Härtela1, Lena Schulza1, Nicole von Wurmb-Schwarka2, Thomas Hoehna3, Angela Kribsa4, Helmut Küstera5, Jens Siegela6, Christian Wiega7, Jan Weicherta8, Egbert Hertinga1, Wolfgang Göpela1 and the German Neonatal Network (GNN)

a1 Department of Pediatrics, University Hospital of Schleswig-Holstein, Luebeck, Germany

a2 Department of Forensic Medicine, University Hospital of Schleswig-Holstein, Kiel, Germany

a3 Department of Pediatrics, University Düsseldorf, Düsseldorf, Germany

a4 Department of Pediatrics, University Köln, Köln, Germany

a5 Department of Pediatrics, University of Göttingen, Göttingen, Germany

a6 Department of Pediatrics, Auf der Bult, Hannover, Germany

a7 Aschaffenburg Department of Pediatrics, Aschaffenburg, Germany

a8 Department of Gynecology and Obstetrics, University Hospital of Schleswig-Holstein, Luebeck, Germany


The increasing rates of preterm birth among twins implicate that solid data on associated risks and outcomes are required. Assessment of zygosity is often based on clinical criteria (evaluation of placenta; same gender, birth weight discordance as surrogate criteria for monochorionic/monozygotic twins). The aim of this study was to compare clinical versus genetic assessment of zygosity and to compare causes of preterm delivery as well as outcome data of very-low-birth-weight (VLBW; birth weight <1,500 g) twins stratified to zygosity. In a multicenter study, we selected n = 176 sets of same gender twins and determined zygosity genetically. In a subgroup of 123 sets of twins, the attending physicians at the study centers were asked to document the parameter ‘zygosity’ (monozygotic/dizygotic) on the basis of their clinical judgment. Concordance between genetic and clinical assessment was 62.7% for monozygotic twins and 88.9% for dizygotic twins, respectively. Outcome parameters (death, BPD, ROP, NEC, IVH) were comparable in both groups. Genetically dizygotic twins were significantly more often born due to intrauterine infection (33% vs. 20% in monozygotic twins, p < .01) and antenatal antibiotics were more frequently given to mothers of dizygotic twins (62% vs. 47% in monozygotic twins, p < .01). Obstetric complications such as twin-twin-transfusion-syndrome were only seen in monozygotic twins as expected. The unexpected increase of antenatal antibiotic treatment and birth due to intrauterine infection in dizygotic twins should be confirmed in additional VLBW twin-cohorts.

(Received September 13 2011)

(Accepted November 14 2011)


  • very preterm infants;
  • twins;
  • zygosity;
  • outcome;
  • causes of delivery;
  • intrauterine infection