Structural changes in human cervical mucus

Indian J Med Res. 1989 Feb;90:44-50.


The crystallization phenomenon of human cervical mucus was investigated with the help of scanning electron microscope. Changes in the conformation of crystals and ferning patterns were studied on different days of the menstrual cycle in both normally ovulating women and those using oral contraceptives. No crystalline structure was found on day 5 in both categories of women, whereas square crystals were observed on day 21 in normal woman. Nature and type of ferning pattern changes seen from days 11 to 14 in normal women were not seen during this period in women who were on oral contraception, instead a thick, viscous mucus was found during the entire period of the cycle.

PIP: Crystal patterns of cervical mucus were observed by electron scanning microscopy in 6 normal women and in women taking oral contraceptives, on Days 5, 11, 14 and 21 of the menstrual cycle. The pills contained 500 mcg norgestrel and 30 mcg ethinyl estradiol (Indian Drugs and Pharmaceuticals Ltd., Hyderabad). Mucus was obtained by aspiration from the cervical canal, smeared and dried at room temperature, and plated for scanning microscopy without fixation. Spinnbarkheit and ferning was noted to increase on Days 11 and 14 in normal cycling women, but rose slightly between Day 5 and 11 and then remained constant in pill cycles. On the scanning microscope, mucus from cycling women was characterized by fern patterns on Days 11 and 14. On Day 11 a rounded, parallel, grooved backbone with flattened branches on only 1 side was observed. The distance between sub-branches was consistent at 3.33 mcm. On Day 14 sub-branching lessened, but branching was commonly located on both sides of the backbone. The distance between sub-branches ranged from 3.75-5.0 mcm. The width of the main backbone was wider than on Day 11, from 6.25-11.25 mcm. In women on the pill, no ferning appeared: mucus remained thick, viscous and tenacious, with no crystalline structure.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Cervix Mucus / cytology*
  • Cervix Mucus / drug effects
  • Contraceptives, Oral, Combined / pharmacology
  • Contraceptives, Oral, Hormonal / pharmacology
  • Crystallization
  • Female
  • Humans
  • Menstrual Cycle*
  • Microscopy, Electron, Scanning


  • Contraceptives, Oral, Combined
  • Contraceptives, Oral, Hormonal