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  • Print publication year: 2021
  • Online publication date: March 2021

Chapter 5 - Conception

from Section 1 - Physiology of Reproduction


Cervical mucus is a regulator of the sperm transfer from the vagina to the uterine cavity. Estradiol (E2) stimulates the production of large amounts of thin, watery, alkaline acellular cervical mucus with ferning, spinnbarkeit (crystallization), and sperm receptivity. Progesterone (P4) inhibits the secretory activity of cellular mucus and produces low spinnbarkeit and absence of ferning, which is impenetrable by spermatozoa. In midcycle, the cervix softens progressively, the os of the cervical canal dilates, and clear, profuse mucus exudes from the external os. In a few days after ovulation, the cervix becomes firm, and the os closes. The cervix is the first barrier for the sperm to overcome.

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