The recipient’s Day after ovulation and the number of corpora lutea influence the likelihood of pregnancy in mares following transfer of ICSI frozen embryos.
Abstract: Asynchronous embryo transfer is an excellent tool to investigate how subtle differences in the uterine environment affect embryo development and survival. Progesterone secreted from the corpus luteum following ovulation is one of the main factors responsible for establishing endometrial receptivity for the pre-implantation embryo via complex alterations in the expression of genes involved in the secretion of the histotroph. The objective of this retrospective study was to determine whether the recipient's Day after ovulation and the number of CL at ET influence the pregnancy rates of IVP horse embryos. The study included 650 heterologous frozen ICSI horse embryo transfer cycles and evaluated the pregnancy and ongoing pregnancy rate. The ongoing pregnancy was significantly lower in recipient mares with ET performed 5 and 6 days after ovulation (47.4% and 37.5%, respectively) than in recipients with ET 4 days after ovulation (67.3%). Furthermore, Day 5 recipient mares (Day 0 = Day of ovulation) with 2 corpora lutea (CL) at the time of ET had lower ongoing pregnancy rate (36.1%) than Day 5 recipient mares with 1 CL (51.9%). In contrast, the presence of 2 CL was associated with a higher ongoing pregnancy rate (75.8%) in recipient mares with a less advanced uterine stage at the time of ET (Day 3 and 4 after ovulation), compared to recipients with only 1 CL at ET (62.7%). In conclusion, both the number of days after ovulation and the number of CL recorded in the recipient mare at ET influenced the ongoing clinical pregnancy rate. This study highlights the importance of establishing exactly when progesterone rises above a threshold (relative to the Day of ovulation) when trying to determine the optimal window for transferring an IVF/IVP embryo.
Copyright © 2019 Elsevier Inc. All rights reserved.
Publication Date: 2019-06-12 PubMed ID: 31226608DOI: 10.1016/j.theriogenology.2019.06.020Google Scholar: Lookup
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- Journal Article
Summary
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The researchers examined the correlations between a mare’s day after ovulation and corpora lutea count on the likelihood of successful pregnancy following transfer of intracytoplasmic sperm injection (ICSI) frozen embryos. They found that the timing of the embryo transfer and the count of corpora lutea significantly affected the rate of sustained pregnancy.
Objective of the Research
- The researchers aimed to determine whether the day after the mare’s ovulation and the number of Corpora Lutea (CL) at the time of Embryo Transfer (ET) have an impact on the success of In-Vitro Produced (IVP) horse embryo’s pregnancy rates.
Methodology and Scope of the Study
- A retrospect study was carried out involving 650 heterologous frozen ICSI horse embryo transfer cycles.
- The study assessed the rates of pregnancy as well as ongoing pregnancy.
Key Findings
- The ongoing pregnancy rates were significantly lower in mares where embryo transfer took place 5 and 6 days after ovulation, with rates of 47.4% and 37.5% respectively.
- Recipients of embryo transfer on the fourth day after ovulation had a higher rate of ongoing pregnancy at 67.3%.
- Mares on day five (considering the day of ovulation as Day 0) with two CL had lower ongoing pregnancy rates (36.1%) compared to those with one CL(51.9%).
- Interestingly, the presence of two CL was associated with higher ongoing pregnancy rates (75.8%) in mares whose embryo transfer happened on days 3 and 4 after ovulation, when compared to mares with just one CL at the time of embryo transfer (62.7%).
Conclusions
- The study concludes that both the number of days after the mare’s ovulation and the number of corpora lutea at the time of embryo transfer played a significant role in determining the ongoing clinical pregnancy rate.
- This underlines the significance of accurately establishing when progesterone levels rise beyond a certain threshold after the day of ovulation to deduce the most effective window for transferring an IVF/IVP embryo.
Cite This Article
APA
Cuervo-Arango J, Claes AN, Stout TA.
(2019).
The recipient’s Day after ovulation and the number of corpora lutea influence the likelihood of pregnancy in mares following transfer of ICSI frozen embryos.
Theriogenology, 135, 181-188.
https://doi.org/10.1016/j.theriogenology.2019.06.020 Publication
Researcher Affiliations
- Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, the Netherlands. Electronic address: j.cuervo-arangolecina@uu.nl.
- Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, the Netherlands.
- Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, the Netherlands.
MeSH Terms
- Animals
- Corpus Luteum / physiology
- Embryo Transfer / veterinary
- Female
- Freezing
- Horses / physiology
- Ovulation / physiology
- Pregnancy
- Pregnancy, Animal
- Sperm Injections, Intracytoplasmic / veterinary
- Tissue Preservation / veterinary
Citations
This article has been cited 3 times.- Cortez JV, Hardwicke K, Méndez-Calderón CE, Grupen CG. Effect of Pre-IVM Duration with cAMP Modulators on the Production of Cloned Equine Embryos and Foals. Animals (Basel) 2025 Jul 3;15(13).
- Newcombe JR, Wilsher S, Cuervo-Arango J. The post-ovulatory rise in progesterone is lower and the persistence of oestrous behaviour longer during the first compared with the second cycle of the breeding season in mares. Reprod Domest Anim 2023 Jan;58(1):141-145.
- Gambini A, Duque Rodríguez M, Rodríguez MB, Briski O, Flores Bragulat AP, Demergassi N, Losinno L, Salamone DF. Horse ooplasm supports in vitro preimplantation development of zebra ICSI and SCNT embryos without compromising YAP1 and SOX2 expression pattern. PLoS One 2020;15(9):e0238948.
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