Importance of uterine expulsion of embryos in the interceptive mechanism of postcoital oestradiol in rats

M. E. Ortiz, G. Bastias, O. Darrigrande, H. B. Croxatto

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)


This study compares the interceptive effectiveness of 1 ftg oestradiol given as a single s.c. injection at 0900 or 1700 hours on Day 1, 2, 3, or 4 of pregnancy in rats. Increasing the interval from ovulation to treatment accelerated the oviducal transport of a larger number of embryos, the majority of which were lost from the genital tract. However, after treatment at 1700 hours on Day 3 the majority of accelerated embryos were retained in the uterus. The number of implanted embryos on Day 14 was equal to the number of eggs remaining in the tract 24 h after treatment. As a consequence, the highest interceptive effectiveness was obtained with treatment given at 1700 hours on Day 2 and at 0900 hours on Day 3 of pregnancy. Accelerated oviducal transport and uterine expulsion of embryos begin to dissociate after Day 2 of pregnancy in the rat. This explains why the most effective treatments to accelerate oviducal transport are not always the most effective to reduce the number of implantations. These data emphasize the importance of retentive and expulsive properties of the uterus for fertility and infertility.

Original languageEnglish
Pages (from-to)333-337
Number of pages5
JournalReproduction, Fertility and Development
Issue number3
Publication statusPublished - 1 Jan 1991


  • Female fertility
  • Ovum transport

ASJC Scopus subject areas

  • Biotechnology
  • Reproductive Medicine
  • Animal Science and Zoology
  • Molecular Biology
  • Genetics
  • Endocrinology
  • Developmental Biology


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