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Evi Timotheou | BcS, MSc

Senior Clinical Embryologist, Lab Director


Evi Timotheou received her Bachelor of Science degree in Biology from University of Bologna, Italy in 2004. Her thesis included research about the influence of different culture systems in human ovarian tissue preservation after cryopreservation.

Evi  began her embryology career in 2004 at University Hospital Sant’ Orsola Malpighi, Institute of Gynecology & Obstetrics, Human Reproduction Unit, Bologna, Italy , trained by Raffaella Fabbri  in freezing / thawing ovarian tissue , ovarian tissue culture and electron microscopy techniques.

She completed her internship in IVF techniques at Ravenna Hospital, Department of Obstetrics & Gynecology, Italy in 2006.

In 2007 she was recruited as embryologist at Genesis IVF Center, Patras, Greece.

She joined American Fertility Services Clinic in New York, USA in 2007 and specialized in assisted reproduction techniques including pre-implantation genetic diagnosis (PGD) and extended embryo culture.


In 2009 Evi joined the Team of embryologists at “IVF Athens Center” in Athens, Greece. She obtained her MSc. in Reproductive Science from University of Athens, Medical School. Her research included use of metabolomics in in-vitro fertilization for the embryo development and their relation with the genetic profile of women.

From 2013 Evi is ESHRE certified Clinical Embryologist.

She joined Assisting Nature as a Senior Embryologist in 2015 and was promoted to Laboratory Director in January 2016. Evi is responsible for all functions of the clinical laboratory including in vitro fertilization, ICSI, assisted hatching, testicular and epididymal sperm preparation, preimplantation genetic diagnosis, oocytes and embryo cryopreservation. Finally she is responsible for the quality assurance and quality control of the Embryology Laboratory. 

She has co-authored numerous research journal articles in her field and is an active member of The European Society of Human Reproduction and Embryology.

Email: [email protected]

Scientific publications, presentations, papers

  1. Timotheou E., Chartomatsidou T., Kostoglou K., Kakani O., Galiotou M., Chouliara F., Najdecki R., Papanikolaou EG., Christopikou D. Neonatal health outcome of offspring born after Preimplantation Genetic Testing for aneuploidies (PGT-A) in IVF, 15th Congress of the European Society of Gynecology, Nov29-Dec2 2023, Amsterdam, Netherlands
  2. Najdecki R, Peitsidis N, Tsakiridis I, Michos G, Timotheou E, Chartomatsidou T, Athanasiadis A, Papanikolaou E. Hysteroscopic Endometrial Fundal Incision in Oocyte Recipients before Embryo Transfer May Improve Reproductive Outcomes: A Prospective Study. Int J Fertil Steril. 2023 Nov 7;18(1):40-44. doi: 10.22074/ijfs.2023.560746.1354. PMID: 38041458; PMCID: PMC10692741.
  3. Peitsidis N, Tsakiridis I, Najdecki R, Michos G, Chouliara F, Timotheou E, Chartomatsidou T, Athanasiadis A, Papanikolaou E. Diagnostic hysteroscopy with endometrial fundal incision may improve reproductive outcomes in oocyte recipients after implantation failure. JBRA Assist Reprod. 2023 Nov 14;27(4):689–93. doi: 10.5935/1518-0557.20230037. Epub ahead of print. PMID: 37962971; PMCID: PMC10718553.
  4. Timotheou E, Chartomatsidou T, Kostoglou K, Katouna A, Christopikou D, Najdecki R, Papanikolaou E. Implantation failure with egg donation after multiple failed IVF cycles with own oocytes; Is it necessary to perform PGT-A?, 19th IAHR World Congress 15-18 March 2023, Venice, Italy.
  5. Najdecki R, Michos G, Peitsidis N, Timotheou E, Chartomatsidou T, Kakanis S, Chouliara F, Mamopoulos A and Papanikolaou E (2022) Agonist triggering in oocyte donation programs—Mini review. Front. Endocrinol. 13:838236. doi: 10.3389/fendo.2022.838236.
  6. Kostoglou K, Chartomatsidou T, Papa E, Chouliara F, Kallintzi M, Timologou A, Papanikolaou E, Najdecki R, Timotheou E. Cumulative live birth rates in egg donation regarding the origin of oocytes (fresh or cryopreserved oocytes) in unsynchronized cycles. ESHRE Annual Meeting 2022 (poster presentation)
  7. Timotheou E, Chartomatsidou T, Kostoglou K, Papa E, Ioakeimidou C, Najdecki R, Papanikolaou E. The correlation of first cleavage and blastulation timing to the euploid status of embryos after PGT-A. ESHRE Annual Meeting, 2021 (poster presentation)
  8. Najdecki R, PapanikolaouE , Chartomatsidou T , Pakaki F, Stamataki S, Tatsi P , Timotheou E,  Chouliara F , Bampas E, Bouchlariotou S, Michos G, Athanasiadis A. Hysteroscopic Fundus Endometrial Incision (FEI) in oocyte recipients before embryo transfer (ET) during In Vitro Fertilization. ESHRE Annual Meeting, 2020 (oral presentation)
  9. Papanikolaou E, Najdecki R, Chouliara F, Tatsi P, Chartomatsidou T , Pakaki F, Stamataki S , Ioakeimidou C, Timologou A, Vlachou C, Diamantopoulos A, Virgiliou A, Kaminski P, Athanasiadis A, Timotheou E. Post Implantation failure diagnostic Hysteroscopy with Endometrial Fundus Incision (FEI) might improve pregnancy outcome in oocyte recipients. ESHRE Annual Meeting, 2020 (poster presentation)
  10. Tatsi P, Chartomatsidou T, Papanikolaou E, Najdecki R, Chouliara F, Asuchidou I, Ioakeimidou C,  Timotheou E. The impact of Vitrification in the outcome of IVF in an oocyte donation program. ESHRE Annual Meeting, 2020 (poster presentation)
  11. Davies S, Christopikou D, Kallioras N, Tsakalis P, Tsorva E, Zaxaria S, Economou K, Najdecki R, Timotheou E, Tatsi P, Chartomatsidou T, Papanikopoulos E, Lagaros N, Mastrominas M, Papanikolaou E. Applied machine learning based on time-lapse technology and reproductive history data designed for pre-implantation embryo ploidy prediction. ESHRE Annual Meeting, 2020 (poster presentation)
  12. Papanikolaou E, Timotheou E, Tatsi P, Chartomatsidou T, Asouchidou I, Grynberg M, Vlachou C, Katsoula E, Najdecki R. Long-Antagonist protocol versus Classical-day-6 Antagonist. Single luteal use of long-acting GnRH-antagonist Degarelix can efficiently downregulate LH during ovarian stimulation for IVF achieving comparable pregnancy outcome. ESHRE Annual Meeting, Vienna 2019 (oral presentation)
  13. Najdecki R, Choulaira F, Timotheou E, Tatsi P, Chartomatsidou T, Asouchidou E, Pakaki F, Bouchlariotou S, Humaidan P, Papanikolaou E. Single follicular degarelix, a new long acting GnRH-antagonist for LH surge suppression during ovarian stimulation in oocyte donors. A randomised controlled trial. ESHRE Annual Meeting, Vienna 2019 (oral presentation)
  14. Timotheou E, Chartomatsidou T, Tatsi P, Katsoula E, Vlachou C, Stamataki S, Asouchidou I, Zafeiratis O, Najdecki R, Papanikolaou E. Cumulative Live Birth Rates (CLBR) in patients following Freeze-all policy are higher compared to patients who undergo fresh embryotransfer (ET) followed by frozen-thawed embryotransfers. ESHRE Annual Meeting, Vienna 2019 (poster presentation)
  15. Papanikolaou E, Chartomatsidou T, Timotheou E, Tatsi P, Katsoula E, Vlachou C, Asouchidou I, Zafeiratis O, Najdecki R. In Freeze-All Strategy, Cumulative Live Birth Rate (CLBR) Is Increasing According to the Number of Blastocysts Formed in Women <40 Undergoing Intracytoplasmic Sperm Injection (ICSI). Front Endocrinol. 2019; 10 (427) https://www.frontiersin.org/articles/10.3389/fendo.2019.00427/full
  16. Papanikolaou EG, Timotheou E, Tatsi P, Janssens H, Grynberg M, Athanasiadis A, Zafeirati C, Najdecki R, Petousis S. COMFFETI, Combined Fresh and Frozen Embryo Transfers per Indvidual: A New Index of Quality Control for the Performance of Embryologic Labs in The Emerging Era of Segmentation of Cycle and Freeze- All Strategy. Int J Fertil Steril. 2019; 12(4): 339-342 https://www.ncbi.nlm.nih.gov/pubmed/30291697
  17. Papanikolaou EG, Yarali H, Timotheou E, Grynberg M, Zafeiratis O, Tournaye H and Najdecki R. A Proof-of-Concept Clinical Trial of A Single Luteal Use of Long-Acting Gonadotropin-Releasing Hormone Antagonist Degarelix in Controlled Ovarian Stimulation for In Vitro Fertilization: Long Antagonist Protocol. Front. Endocrine. 2018. 9:25. doi: 10.3389/fendo.2018.00025     https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5839166/
  18. Papanikolaou EG, Yarali H, Timotheou E, Tatsi, P, Chartomatsidou T, Grynberg M, Zafeiratis O, Vlachou C, Tournaye H  and Najdecki R. Long-Antagonist protocol; single luteal use of long-acting GnRH-antagonist Degarelix can efficiently downregulate LH during ovarian stimulation for IVF. A proof of concept. ESHRE Annual Meeting, Barcelona 2018 (Award nominee)
  19. Chartomatsidou T, Timotheou E, Tatsi P, Katsoula E, Zafeiratis O, Najdecki R, Papanikolaou E. In Freeze-all strategy Cumulative Live Birth Rate (CLBR) is increasing according to the number of blastocysts formed in women <40 undergoing Intracytoplasmic Sperm Injection (ICSI). ESHRE Annual Meeting, Barcelona 2018
  20. Papanikolaou E, Timotheou E, Tatsi P, Chartomatsidou T, Najdecki R. Long-Antagonist protocol; luteal administration of a single dose of Degarelix (long-acting GnRH-antagonist) for controlled ovarian stimulation. A new protocol for IVF. ASRM Scientific Congress & Expo, Denver, Colorado, 2018
  21. The 20th World Congress on Controversies in Obstetrics, Gynecology & Infertility (COGI) Paris 2014: oral presentation
  22. Influence of protein supports on ovarian tissue cryopreservation”. 7th World Congress on Controversies in Obstetrics Gynecology & Infertility, Athens. R. Fabbri, S. Di Tullio, G Bracone, E. Timotheou, G. Pasquinelli, B. Mozzanega, S. Venturoli.
  23. «1st National Workshop Theorical-Practical of Human Ovarian Tissue Cryopreservation», S. Orsola-Malpighi Hospital, Bologna, Italy (speaker & supervisor)
  24. Clinical and Molecular description of Prenatal Diagnosis fetal micro size 2.5 Mb duplication in the region 22q11.2 maternal origin”.Christopoulou G., Sismani K., Sakellariou Μ., Timotheou Ε., Magkana Μ., Koutsouni Α., Kostomenos D., Ntoutsoulis G., Velissariou V., Αthanassiou V.
  25. Birth of healthy baby after Preimplantation Genetic Diagnosis and Vitrification of a Woman with Achondroplasia. 17th National Congress of Perinatal Medicine. Athens. Sakellariou Μ., Bili C., Florentin L., Timotheou Ε., Magkana Μ., Koutsouni Α., Pitta P., Gouedard C., Kostomenos D., Ntoutsoulis G., Αthanassiou V.
  26. “Γέννηση υγιούς παιδιού μετά από Υαλοποίηση ωαρίων και Κρυοσυντηρημένο Ορχικό Ιστό: CaseReport. 12ο Πανελλήνιο Συνέδριο Μαιευτικής- Γυναικολογίας. Thessaloniki. Μ. Sakellariou, Ε. Timotheou, Μ. Magkana, Α.Κ. Koutsouni, G. Nikolopoulos, G. Ntoutsoulis, D. Kostomenos, V. Athanassiou.
  27. The impact of zona pellucida thickness on day-5 blastocysts in clinical. Vasilios Athanassiou, Evangelia Timotheou, Georgios Ntoutsoulis, Dimitrios Kostomenos, Georgios Nikolopoulos, Maria Sakellariou.
  28. Prolonged warming period improves clinical pregnancy rate of early day-5 vitrified blastocyst. Vasilios Athanassiou, Maria Sakellariou, Georgios Nikolopoulos, Dimitrios Kostomenos, Georgios Ntoutsoulis, Evangelia Timotheou.