By Iván Ferrer Durbà BSc (biologist & science teacher).
Last Update: 04/04/2014

The neck of the uterus or uterine cervix is the lower fibromuscular region of the uterus which projects into the vagina.

This opening allows the scape of blood from the uterus during menstruation and the entrance of sperm cells into the uterus and into the fallopian tubes.

Cervix and pregnancy

The size and consistency of the orifice and the cervix position may experience a number of changes during pregnancy and menstrual cycle regarding to:

  • The degree of dilatation of the orfice: open cervix or closed cervix.
  • Consistency: hard cervix or soft cervix.
  • Position: high cervix (posterior or isolated of the vagina) or low cervix (more inside the vagina).
  • Cervix position at the beginning of pregnancy, it varies widely from woman to woman.

Cervix position at the beginning of pregnancy

The position of the cervix varies a lot from woman to woman, therefore, the position of the neck of the uterus is not a reliable indicator of pregnancy.

Nevertheless, some changes in the position and texture of the uterine cervix take place during the early stages of pregnancy in all women.

Changes in the cervix during pregnancy

  • From the beginning of pregnancy, the uterine cervix softens and it turns bluish as a consequence of the increase of the vascularisation, the lump and the size of cervical glands.
  • The cervix must go up slightly towards the uterus. Depending on the stage of the menstrual cycle in which the woman conceives, this change can take place in a few days or one month.

Cervix position after pregnancy

  • Its collagen fibres are rearranged, its resistance decreases drastically and it makes easier its dilatation in labour.
  • Shortly after the conception a thick cervical secretion obstruct the cervical canal forming a mucous plug which seals it acting as a barrier against the transport of sperm and the invasion of bacteria. This plug is expelled during the beginning of labour.

Authors and contributors

 Iván Ferrer Durbà
BSc
Biologist & Science Teacher
Bachelor's Degree in Biology by the University of Valencia (UV). Postgraduate Course in Secondary Education and Teaching by the University of Portsmouth. Teacher of Sciences at multiple British schools and high schools. More information