An introduction to and some new anatomical and physiological aspects of the cervix and vagina are presented and also an explanation of the biosynthesis and molecular structure of mucus.
Canalization of cervical mucus from 31 patients at the obstetric/gynecologic clinic at the Universita Cattolica del S. Cuore in Rome, Italy has studied to determine the biochemical basis of canalization and its dependence on estrogen, to study the action on the canalization of hormones used to induce ovulation, and to correlate fern pattern and canalization. Cervical mucus was collected daily and applied to a glass slide, covered with an object cover, and allowed to dry. The typical arrangement of the dendritic crystals and the presence of channels among them were confirmed. Depending on the phase of the ovulatory cycle, the crystals differed in direction and in number. The number of channels consistently increased as estradiol levels increased during the proliferative phase. This happened in both natural and induced ovulatory cycles. The cervical mucus of patients with primary amenorrhea canalized when treated with estrogens. The channels ran parallel to each other. Yet, during the secretory phase, the number of channels fell rapidly and the channels were lined up in a crisscross fashion. This suggested that sperm penetration is dependent on the orientation of mucus crystals. Indeed in vitro studies showed that spermatozoa enter the periovulatory mucus in tightly packed files as if the mucus allowed only passage in this linear formation. The biophysical characteristics of canalization paralleled those of ferning. Moreover, like ferning, the presence of essential salts and proteins induced canalization. It is concluded that canalization can be used to accurately measure estradiol levels and thus to detect ovulation.
In order to evaluate the relationship between the urinary luteinizing hormone (LH) surge as detected by the OvuSTICK (Monoclonal Antibodies, Inc., Mountain View, CA) method and daily cervical mucus parameters, ten spontaneously ovulating women undergoing infertility evaluation were followed during their cycles with twice daily urinary LH testing as well as daily ultrasound, mucus evaluation, and hormonal assays of serum LH, progesterone (P), and estradiol (E2). Maximal cervical mucus scores, as determined using a modified Insler score, were noted to coincide consistently with the urinary LH surge as detected by twice daily testing and to precede ultrasound evidence of ovulation by 0 to 24 hours. Mucus scores rapidly declined in the 24-hour period following the urinary LH surge. Detection of the urinary LH surge may therefore help identify that period of time during which cervical mucus parameters are optimal and therefore facilitate the timing of artificial insemination, intercourse, or postcoital testing.
12 normal ovulatory women were studied during 17 menstrual cycles. The first day on which the women had increasing quantities of 0.1 ml or more clear cervical mucus (IQCCM) was closely related to the time of ovulation as monitored by basal body temperature and radioimmunoassay of serum-luteinizing hormone, follicle-stimulating hormone, estradiol, and progesterone. The results show that the time of ovulation can be predicted clinically without specialized tests by observing the day of onset of IQCCM.
The cervical canal mucus is important to human fertility since conception can only occur if sperm pass through the contents of the cervical canal to reach the ovum. The biophysical properties of the cervical mucus and their relation to sperm migration are, therefore, curcial. A variety of laboratory experimentation methods have been used 1) sperm migration measurements; 2) reheological studies; 3) cell countings; 4) crystallization studies; 5) 6) EPR; and 7) photoelectron spectroscopy. Cervical mucus is the end result of complicated biosynthetic processes occurring in the epithelial cells of the cervical mucosa; this biosynthesis is regulated by many factors. Type E, characteristic for estrogenic stimuli on mucus biosynthesis, and type G, for gestagenic stimulation, are the 2 main types of cervical secretions. The 2 types always occur together, in differing proportions. For example, at normal ovulation there is a 97:3 ratio of type E to type G; at normal corpus luteum, the ratio is 10:90. The string variety of type E seems to aid in conveying sperm from the vagina while the loaf variety is inactive. The very low viscosity of the string variety intermicellar fluid permits very rapid sperm swimming. Not much is known regarding cervical mucus pathology or therapy.