Doppler ultrasonography for selection of recipients in embryo transfer programs

This study was interesting not only for its relevance to embryo transfer programs but also for the possibility of assessing the reproductive health of all bred mares. Assessing the corpus luteum for blood flow may help answer the question of whether she is susceptible to early embryonic resorption/abortion. Early intervention may be beginning progesterone supplementation. It does require a Doppler ultrasound and an experienced person operating the ultrasound. This use needs to be confirmed with further studies but this study surely has researchers thinking.
DrO

Use of Doppler ultrasonography for selection of recipients in embryo transfer programs in horses
Theriogenology. 2023 Aug 18;211:142-150. doi: 10.1016/j.theriogenology.2023.08.012. Online ahead of print.
Authors
Karine Galhego Morelli 1 , Gilberto Guimarães Lourenço 2 , Vinicius Rodrigues Marangon 3 , Isabella Rio Feltrin 4 , Thaís Sayuri Imura Oshiro 5 , Igor Vicente Rodrigues da Silva 6 , Guilherme Pugliesi 7
Affiliations

1 USP – Universidade de São Paulo, Avenida Duque de Caxias Norte 225, Jardim Elite, Pirassununga, SP, Brazil. Electronic address: karinemorelli@usp.br.
2 M.V. Haras Laglória – Médico Veterinário responsável pelo Haras Laglória, Fazenda Salgada, 00000 – RT-19, Itajara-Itaperuna, RJ, Brazil. Electronic address: guaravetufv@yahoo.com.br.
3 UNIG – Universidade Iguaçu – Itaperuna – Campus V – R356, 02 – Cidade Nova, Itaperuna, RJ, Brazil. Electronic address: vinicius.r.m@hotmail.com.br.
4 UNESP – Botucatu – Universidade Estadual Paulista “Júlio de Mesquita Filho”, Distrito de Rubião Júnior, s/n – Rubião Junior, SP, 18618-970, Brazil. Electronic address: isabella.feltrin@yahoo.com.br.
5 USP – Universidade de São Paulo, Avenida Duque de Caxias Norte 225, Jardim Elite, Pirassununga, SP, Brazil. Electronic address: thais.imura@usp.br.
6 UNIPAC-JF, Faculdade Presidente Antonio Carlos, Juiz de Fora Av. Juiz de Fora, 1100, Granja Betânia, Juiz de Fora – MG, 36048-000, Brazil. Electronic address: igor2325@hotmail.com.
7 USP – Universidade de São Paulo, Avenida Duque de Caxias Norte 225, Jardim Elite, Pirassununga, SP, Brazil. Electronic address: gpugliesi@usp.br.

PMID: 37634355
DOI: 10.1016/j.theriogenology.2023.08.012

Abstract

We aimed to evaluate the impact of corpus luteum (CL) and uterine characteristics accessed by B-mode and Color-Doppler ultrasonography in recipient mares at the time of embryo transfer (ET) on pregnancy outcomes. Recipient mares (n = 110), between days 3-9 after spontaneous ovulation, received a fresh embryo. Immediately before ET, the reproductive system was assessed by transrectal palpation for the following parameters: uterine tone (0-3), CL echogenicity (0-6), CL type (homogeneous, trabecular or anechoic center), luteal area (cm2), uterine echogenicity (0-3), uterine edema (0-3), luteal blood perfusion (0-100%) and uterine blood perfusion (1-4). Additionally, a blood sample was collected by puncture of the jugular vein for plasma P4 dosage. Retrospectively, recipients were classified according to the luteal area (small [≤ 6 cm2] or large [> 6 cm2]), luteal blood perfusion (low [≤ 55%] or high [> 55%]), and plasma concentration of P4 (low ≤ 9.98 ng/mL or high > 9.98 ng/mL). Pregnancy diagnosis was performed at 12 and 30 days of gestation. Luteal blood perfusion was significantly higher (P = 0.04) in pregnant recipients (n = 83) than in non-pregnant recipients (n = 27). Overall P/ET was higher (P ≤ 0.02) in mares with high luteal blood perfusion and high P4. Luteal blood perfusion was the most adequate significant (P = 0.01) predictor of pregnancy compared with the luteal area and plasma P4 concentration. Only luteal blood perfusion showed a linear (P = 0.03) and cubic (P = 0.004) effect on P/ET. In conclusion, CL blood perfusion determined by color-Doppler can be used in real-time to select recipients with the greatest chance of maintaining pregnancy in equine ET programs.

Keywords: Blood perfusion; Color Doppler; Corpus luteum; Recipient mares.