Open Access Highly Accessed Review

Pronuclear morphology evaluation in in vitro fertilization (IVF) / intracytoplasmic sperm injection (ICSI) cycles: a retrospective clinical review

Alessia Nicoli1*, Francesco Capodanno1, Ilaria Rondini1, Barbara Valli1, Maria Teresa Villani1, Daria Morini1, Leonardo De Pascalis2, Stefano Palomba1 and Giovanni Battista La Sala1

Author Affiliations

1 Department of Obstetrics, Gynecology and Pediatrics, Sterility Centre P. Bertocchi, Obstetrics and Gynecology Unit, A.O. S.Maria Nuova, IRCCS, Reggio Emilia and University of Modena, Reggio Emilia, Italy

2 Department of Psycology, University of Bologna, Bologna, Italy

For all author emails, please log on.

Journal of Ovarian Research 2013, 6:1  doi:10.1186/1757-2215-6-1

Published: 3 January 2013



The assessment of the embryo quality is crucial to maintain an high pregnancy rate and to reduce the risk of multiple pregnancy. The evaluation of the pronuclear and nucleolar characteristics of human zygote have been proposed as an indicator of embryo development and chromosomal complement. The aim of the current study was to assess the role of pronuclear morphology evaluation in vitro fertilization (IVF) / intracytoplasmic sperm injection (ICSI) cycles.


Retrospective clinical analysis on 755 non-elective transfers of only one embryo (ET). Embryo assessment was performed in days 1 and 2. Clinical and biological data were recorded and analyzed according to embryo and/or pronuclear morphology.


Both pronuclear and embryo morphology were significantly related to clinical pregnancy and live-birth rates. No significant difference in clinical pregnancy and live-birth rates was detected when the pronuclear and embryo morphology assessments were combined. Embryo morphology and maternal age were the only independent predictors of favorable outcome by logistic regression analysis.


Pronuclear evaluation is effective to select the best zygotes if ET is performed at day 1, whereas it did not improve the clinical outcomes when combined with embryo morphology evaluation in day 2.

Embryo morphology; IVF; ICSI; Pregnancy; Pronuclear morphology; Live-birth