A New Year: The perfect time to learn about the cervix

by Amaryllis Sánchez Wohlever, MD
January 31, 2018

Did you know that January is #CervicalHealthMonth? To raise awareness of this hidden but important structure, we continue our series on cervical health started by Dr. Sarah Murray in 2017.

The beginning of a new year is the perfect time to devote to cervical awareness. Why? Consider the importance of cervical health to fertility. A healthy cervix that produces fertile mucus in a cyclical, predictable pattern is central to fertility and our ability to learn the signs of fertility and infertility. We know that for a child to be conceived, three critical components must be present: a healthy egg, sperm, and cervical mucus. Just as a new year begins, it’s important to remember that the cervix and the fluid it produces are essential for a new human life to begin.

As a new cycle in our 12-month calendar begins, we continue to learn from Dr. Erik Odeblad’s groundbreaking research and add more practical science to his tremendous foundation. If we ever thought the cervix is simple and static, scientists continue to prove us wrong. We are grateful to the authors of Current Medical Research for allowing us to share this article.

Biologists Confirm Cervical Mucus Classifications and Propose Four New Structural Types

Cellular biologists from the University of Murcia, Spain confirmed the Odeblad morphological classification system of cervical mucus by using light (LM) and scanning electron microscopy (SEM) to view 230 samples of cervical mucus from 195 women participants.(1) The samples were placed on glass slides and either air-dried or fixed (i.e., prepared) with a chemical called gluteraldehyde. One hundred eighty of these samples were taken from the core of the cervix by use of an insulin syringe. Another 50 samples were taken from various crypts from the cervix by use of a small pipette.

The Spanish biologists were able to identify four mucus types previously described by Odeblad. These four types are based on characteristic ferning patterns of dried cervical mucus and include L mucus, S mucus, G mucus, and P mucus. They were able to identify 3 subtypes of S mucus (S1, S2, and S3) and 5 subtypes of the P mucus (P6B, Pa, P2, P4, and Pt). They also confirmed that various zones and crypts in the cervix produce a specific type of mucus. The Zone of the L crypts produced mostly L mucus, the Zone of the S crypts produced S mucus, the Zone of the G crypts produced G mucus, and the Zone of the P crypts produced P type mucus.

What is new is that the biologists were able to observe and describe 4 different structural types of cervical mucus.

Type I mucus looks compact, with large plain surfaces and small pores. This type came from samples with a high percentage of G mucus.

Type II mucus did not appear as compact as Type I. Its structure looked similar to a marine sponge, with slightly bigger pores. This type came from samples with a high percentage of L mucus.

Type III mucus had a network of parallel and crossing fibers with large diameter pores. The pores were large enough for sperm to penetrate. This type was identified primarily from samples containing S type mucus.

Type IV mucus had plain surfaces and parallel folds. The pore diameters were smaller than those found in Type III mucus. This type came from samples with at least 50% of P type mucus.

The Spanish researchers concluded that they did not view cervical mucus as a homogeneous entity but as a mosaic of four different types in various proportions during the menstrual cycle. They also concluded that specific mucus types are located in specific areas of the cervix. They added that further studies are needed to determine if these different mucus types have biochemical differences.

Comments from Current Medical Research

The authors stated that depending on the day of the menstrual cycle that the mucus sample was taken, the cyclical changes in the ferning patterns of the mucus could be expressed in percentages. Furthermore, they mentioned that this quality (and the technique of observing air dried mucus through a microscope) could have applications in natural family planning.

Richard Fehring, editor of Current Medical Research, cautions that this methodology would have to be demonstrated through research before being used by couples for family planning. The biologists in this study used very sophisticated and powerful microscopes with grids in the field of vision to estimate the percentages of the various types of mucus. The small handheld microscopes available commercially would not match such precision. Furthermore, researchers would have to verify the accuracy of identifying these mucus types in correlation with other valid markers of fertility.

1. Menarguez, M., Pastor, L.M., & Odeblad, E. Morphological characterization of different human cervical mucus types using light and scanning electron microscopy. Human Reproduction, 2004;18:1782-1789.

Text taken from Current Medical Research, Vol. 15, Nos. 3 & 4. © 2004, NFP Program, USCCB, Washington, DC. Used with permission.

FACTS Editorial Note

So, you see, there is much more to the cervix than meets the eye. Situated at the very end of the uterus, this important reproductive organ contains a vital mosaic of fluid that aids in the transport of sperm to meet the egg, leading to the miracle of a unique new life. This research holds much promise for possible future applications for FABMs.

To learn more about the cervix and its important role in reproductive health as well as family planning, read Dr. Murray’s 3-part series on cervical health.