Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Clinical Trial
. 2010 Jun 25:8:77.
doi: 10.1186/1477-7827-8-77.

Analysis of pronuclear zygote configurations in 459 clinical pregnancies obtained with assisted reproductive technique procedures

Alessia Nicoli  1 , Francesco Capodanno, Lucia Moscato, Ilaria Rondini, Maria T Villani, Antonella Tuzio, Giovanni B La Sala
Affiliations
Clinical Trial

Analysis of pronuclear zygote configurations in 459 clinical pregnancies obtained with assisted reproductive technique procedures

Alessia Nicoli et al. Reprod Biol Endocrinol. .

Abstract

Background: Embryos selection is crucial to maintain high performance in terms of pregnancy rate, reducing the risk of multiple pregnancy during IVF. Pronuclear and nucleolar characteristics have been proposed as an indicator of embryo development and chromosomal complement in humans, providing information about embryo viability.

Methods: To correlate the zygote-score with the maternal age and the outcome of pregnancy, we analyzed the pronuclear and nucleolar morphology, the polar body alignment and the zygote configuration in 459 clinical pregnancies obtained by IVF and ICSI in our public clinic in Reggio Emilia, Italy. We derived odds ratios (OR) and Corenfield's 95% confidence intervals (CI). Continuous variables were compared with Student's t-test; P lower than .05 was considered statistically significant.

Results: We observed a significant increase of "A" pronuclear morphology configuration in 38-41 years old patients in comparison to that lower than or equal to 32 years old and a significant decrease of "B" configuration in 38-41 years old patients in comparison to that lower than or equal to 32 and in comparison to that of 33-37 years old. Related to maternal age we found no significant differences in P1 and in P2 configuration. We found no correlation between zygote-score, embryo cleavage and embryo quality.

Conclusions: Our results confirm the limited clinical significance of zygote-score suggesting that it can not be associated with maternal age, embryo cleavage and embryo quality. The evaluation of embryo quality based on morphological parameters is probably more predictive than zygote-score.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Different configurations used for pronuclear morphology, nucleolar morphology and polar body alignement assessment. Pronuclear morphology is classified as A-E, nucleolar morphology is classified as 1-4 and polar body alignement is classified as α, β or γ (9).
Figure 2
Figure 2
Zygotes showing different distribution of NPB in the 2PN and different PB aligment (Original magnification ×400). Zygotes observed after 18-20 hours after insemination. (A) 2PN centralized and juxtaposed, NPBs aligned on the side of the 2PN, longitudinal PB alignment. (B) 2PN centralized and juxtaposed, NPBs dispersed in the 2PN, perpendicular PB alignment. (C) 2PN centralized and juxtaposed, NPBs non polarized with dispersed or not completely aligned NPBs in the 2PN, longitudinal PB alignment. (D) 2PN centralized and juxtaposed, NPBs aligned on the side of the 2PN, neither longitudinal nor perpendicular PB alignment. Black narrows indicate the PBs. (A) and (B) were examples of zygotes included in Pattern 1 group, while (C) and (D) were examples of zygotes included in Pattern 2 group.
Figure 3
Figure 3
P1 and P2 distributions in ongoing pregnancies/deliveries group. Pattern 1 (P1) and Pattern 2 (P2) distributions in ongoing pregnancies/deliveries groups. We classified any zygote as P1 or P2 on the basis of 2PN zygote score: we considered P1 all zygotes classified as A1α, A2β and A3β, and P2 all the other zygotes.
See this image and copyright information in PMC

References

    1. Cummins JM, Breen TM, Harrison KL, Shaw JM, Wilson LM, Hennessey JF. A formula for scoring human embryo growth rates in vitro fertilization: its value in prtedicting pregnancy and in comparison with visual estimates of embryo quality. J In Vitro Fert Embryo Transf. 1986;3(5):284–295. doi: 10.1007/BF01133388. - DOI - PubMed
    1. Puissant F, Van Rysselberge M, Barlow P, Deweze J, Leroy F. Embryo scoring as a prognostic tool in IVF treatment. Hum Reprod. 1987;2(8):705–708. - PubMed
    1. Shulman A, Ben-Nun I, Ghetler Y, Kaneti H, Shilon M, Beyth Y. Relationship between embryo morphology and implantation rate after in vitro fertilization treatment in conception cycles. Fertil Steril. 1993;60(1):123–126. - PubMed
    1. Balaban B, Yakin K, Urman B, Isiklar A, Tesarik J. Pronuclear morphology predicts embryo development and chromosome constitution. Reprod Biomed Online. 2004;8(6):695–700. doi: 10.1016/S1472-6483(10)61651-3. - DOI - PubMed
    1. La Sala GB, Nicoli A, Villani MT, Gallinelli A, Nucera G, Blickstein I. Spontaneous embryonic loss rates in twin and singleton pregnancies after transfer of top- versus intermediate-quality embryos. Fertil Steril. 2005;84(6):1602–1605. doi: 10.1016/j.fertnstert.2005.05.045. - DOI - PubMed

Publication types