G,L,S & P Mucus

G Mucus (Gestogenic)

G Mucus

G mucus is a high-viscosity elastic stopper which acts as a natural barrier to sperm. (Fig. 11-11). G mucus is present in the cervical canal in all phases of the menstrual cycle except during the fertile phase and menstruation. G mucus secretion is stimulated by progesterone and is produced in the G crypts at the lower end of the cervix in the infertile phase of the cycle. Usually no sensation is associated with G mucus, and the days are dry during the infertile phase.1,2

Fig. 11-11; Structure of G Mucus: A diagram of the structure of G mucus which acts as a complete barrier to the movement of sperm in the cervical canal. >>

In the beginning of a normal menstrual cycle shortly after menstruation, the G mucus fills up the cervical canal, and this also occurs after ovulation, acting as a barrier between the vagina and body of uterus. G mucus contains immunoglobulins and other anti-microbial agents, protecting the upper genital organs.3

References:

  1. Odeblad Erik; ‘Cervical mucus and their functions; Journal of the Irish Colleges of Physicians and Surgeons, Jan 1997, Vol 26, No1.;page 28, 29, 30
  2. Odeblad, E; ‘The discovery of different types of cervical mucus and the Billings Ovulation Method’ page 10, 11, 14, 15, 18 ; Bulletin of the Ovulation Method Research and Reference Centre of Australia, Vol 21, No3; 3-35; Sept 1994. ( google ‘Erik Odeblad, cervical mucus’.)
  3. Odeblad E, ‘Investigations on the physiological basis for fertility awareness; Bulletin for the Ovulation Method Research and Reference Centre of Australia, vol 29, no 1, p2-11, march 2002, (internet, Billings Ovulation Method. www.woomb.org

 

L Mucus (Oestrogenic)

L mucus (Fig. 11-12) is secreted during the whole fertile phase, in the L-secreting crypts which are distributed along the whole cervical canal, but dominating the lower half of the canal,4 and its production is stimulated by medium levels of oestrogen. When oestrogen begins to rise, the L cells begin to produce mucus. L mucus is the first oestrogenic type mucus to be secreted. L mucus is more fluid and begins to descend through the vagina and reach the vulva, initially dislodging the plug of G mucus which then flows to the vulva.1 This downflow is facilitated by the mucolytic activity of P2 mucus which is at its maximum level at the beginning of the fertile phase. When the L mucus exceeds 50% of the total mucus, the woman perceives the beginning of the fertile phase as a change in the character of the vaginal outflow.2 L mucus is sticky, a bit elastic and is either opaque or translucent.1 L mucus is responsible for the typical ferning pattern that has long been associated with cervical mucus.

B

L Mucus

L-mucus has four functions:

(a) The alkaline L-type mucus neutralizes the acidic vaginal secretions to provide a hospitable medium for sperm survival. Sperm die rapidly-perhaps within 30 minutes in the acid environment of the vagina in the infertile phase, but may survive up to five days in fertile-type mucus.(1)

<< Fig. 11-12; Structure of L Mucus: Diagram of L mucus filtering defective sperm, and S mucus transporting sperm in the swimming lanes.

(b) L mucus supplies a supportive framework for the S-mucus swimming lanes.3 Both L and S mucus co-operate to bring about optimal sperm propagation to a crypt.

(c) L mucus has a medium viscosity and it acts as a biological filter to weed out defective sperm.2

(d) L mucus closes the opening of the S crypts once they have been filled with approximately 20-30 spermatozoa.1

References:

  1. Klaus, H; ‘Natural family planning – Is it scientific? Is it effective?’ see page 4, 9, 10; Newman Lecture Series 1 -May 21, 2000. (on the internet; google ‘natural family planning, Dr Hanna Klaus’).
  2. Odeblad Erik; ‘Investigations on the physiological basis for fertility awareness; Bulletin for the Ovulation Method Research and Reference Centre of Australia, vol 29, no 1, p2-11, march 2002, (internet, Billings Ovulation Method, www.woomb.org )
  3. Odeblad, E; ‘The discovery of different types of cervical mucus and the Billings Ovulation Method’ page 10, 11,14, 15, 18 ; Bulletin of the Ovulation Method Research and Reference Centre of Australia, Vol 21, No3; 3-35; Sept 1994. (google ‘Erik Odeblad, cervical mucus’.)
  4. Menarguez M, Pastor LM, Odeblad, E. 2003; ‘Morphological characterization of different human cervical mucus types using light and scanning electron microscopy; Human Reproduction; Vol. 18 No 9, 1782-1789, Sept 2003; (google Erik Odeblad).

S Mucus (oestrogenic)

S Mucus (Fig. 11-13) from the S crypts in the upper half of the cervix appears 1-3 days later then the L mucus. The higher levels of oestrogen stimulate its production. The S mucus is fluid and when it reaches the same amount as the L mucus, the woman notices a change in the character of mucus to a wetslippery sensation at the vulva that remains until peak day. After one or two days, the oestrogen reaches a maximum level, as also does the S mucus.2 The S mucus transports and nourishes sperm. S mucus is very fluid and it forms swimming lanes in which sperm cells move along the cervical canal very rapidly, reaching the S crypts in the cervix in 3-10 minutes.3,7 Both L and S mucus cooperate to bring about an optimal sperm propagation to a crypt.

S Mucus

The qualities of more-fertile mucus – clear, stretchy, spinnbarkeit, associated with a sensation of wetness, slipperiness or lubrication are due to the combined effects of L, S and P mucus. S mucus nourishes sperm in the crypts.(1) Sperm can survive in the oestrogenic more-fertile mucus for up to five days.

<< Fig. 11-13; Structure of S Mucus: Diagram of sperm swimming up the cervical canal in the swimming lanes of S mucus. The L mucus acts as a filter for defective sperm.

S crypts and pre-menopause (aging of the cervix): The cervix ages naturally from birth to post-menopause. At puberty S crypts are very numerous but with increasing age L crypts replace S crypts.6 In the pre-menopause the decrease in number of S crypts results in a decrease in the number of days of more-fertile mucus. When the cervix has aged, a woman may ovulate but yet produce no cervical mucus. Since the mucus is essential for sperm entry, even though the woman may have a biphasic temperature, such women are said to have non-fertile ovulations.1 Pregnancy stimulates the production of S crypts and rejuvenates the cervix by two to three years.6

S crypts and hormonal contraception (the ‘Pill’): (Oral contraceptives double the functional rate of aging of the cervix.6 “After three and up to fifteen months of contraceptive use, there is a greater loss of the S crypt cells than can be replaced”.5

References:

  1. Klaus, Hanna; ‘Natural family planning – Is it scientific? Is it effective?’ see page 4, 13; Newman Lecture Series 1;May 21, 2000. ( on the internet; google ‘natural family planning, Dr Hanna Klaus’).
  2. Odeblad Erik; ‘Investigations on the physiological basis for fertility awareness; Bulletin for the Ovulation Method Research and Reference Centre of Australia, vol 29, no 1, p2-11, march 2002, (internet, Billings Ovulation Method, www.woomb.org)
  3. Odeblad, E; ‘The discovery of different types of cervical mucus and the Billings Ovulation Method’ page 10, 11, 14, 15, 18 ; Bulletin of the Ovulation Method Research and Reference Centre of Australia, Vol 21, No3; 3-35; Sept 1994. (google ‘Erik Odeblad, cervical mucus’.)
  4. Odeblad E; ‘Some notes on the biology of the cervix’ 2007 (internet, google ‘Erik Odeblad, cervical mucus’)
  5. Odeblad E; “Some notes on the cervical crypts”; Bulletin of the ovulation method Research and reference centre of Australia, vol 24 no 2 June 1997, p31.
  6. Klaus, H ; Natural Family Planning : A Review 2nd Edition. July 1995, page 6; NFP Center of Washington, D.C. Inc. , 8514 Bradmoor Drive, Bethesda, MD 20817-3810
  7. Fordney Settlage, Diane S, et al; ‘Sperm transport from the external cervical os to the fallopian tubes in women : A time and quantitation study’ Fertil and Steril; Vol 24, No 9, Sept 1973

P Mucus (oestrogenic)

P mucus was first identified in 1990.6 P mucus is secreted in the upper part of the cervical canal,3,5 and nor adrenaline and oestrogen stimulate the secretion of P mucus.1 P mucus has a number of subtypes but the most important are called P2 and P6. P mucus has two functions; (i) P2 has a mucolytic action (dissolves mucus), and (ii) P6 has the capacity to conduct sperm cells from the S crypts to the uterine cavity.

  • (i) P2 Mucus: P2 mucus is secreted in the crypts in the upper half of the cervix5 and is at its maximum at the beginning of the fertile phase (4-8 days before ovulation).2 It has mucolytic activity, and its physiological role may be to liquefy the G mucus to give space for the L mucus, and to liquefy the L mucus to facilitate the S mucus flow which is necessary for sperm propagation to the crypts. After the sperm has resided in the S crypts, mucolysis may help to liquefy the L mucus now blocking the crypt outlets, so that sperm can continue upwards.2,4
  • (ii) P6 Mucus: P6 mucus is secreted in the upper one-sixth of the cervical canal at its junction with the body of the uterus, (isthmus).3,5 P6 begins to appear in rising quantity at the end of the fertile phase mainly at and shortly after ovulation and it conducts sperm cells from the S crypts to the uterine cavity.4 P6 mucus is present on maximum amount on peak day and its presence is associated with the sensation described as extremely lubricative and slippery.2 The S mucus seldom reaches 35% and the P6 mucus seldom reaches more than 10%, but still changes the quality of sensation to an extremely slippery and lubricative sensation. A contributary factor to this sensation is probably an increase of the mucolytic activity. Mucolysis may in some cases be excessive. This results in a loss of continuity of mucus, the vaginal outflow becomes watery and loss of slipperiness and lubrication occurs.2

References:

  1. Klaus, Hanna; ‘Natural family planning – Is it scientific? Is it effective?’ see page 4; Newman Lecture Series 1 -May 21, 2000. ( on the internet ; google ‘natural family planning, Dr Hanna Klaus’).
  2. Odeblad Erik; ‘Investigations on the physiological basis for fertility awareness; Bulletin for the Ovulation Method Research and Reference Centre of Australia, vol 29, no 1, p2-11, march 2002, (internet, Billings Ovulation Method, www.woomb.org)
  3. Menarguez M, Pastor LM, Odeblad, E. 2003; ‘Morphological characterization of different human cervical mucus types using light and scanning electron microscopy; Human Reproduction; Vol. 18 No 9, 1782-1789, Sept 2003; available on the internet if you google Erik Odeblad).
  4. Hume K, ‘The biology of the cervix 1998; (internet, google bDr Kevin Hume, cervical mucus’)
  5. Odeblad Erik; ‘Cervical mucus and their functions';Review article, J of the Irish Colleges of Physicians and Surgeons, Vol 26, No1, Jan 1997 p27-32
  6. Odeblad, E; ‘The discovery of different types of cervical mucus and the Billings Ovulation Method’ page 10, 11, 14, 15, 18 ; Bulletin of the Ovulation Method Research and Reference Centre of Australia, Vol 21, No3; 3-35; Sept 1994. ( google ‘Erik Odeblad, cervical mucus’.)

To be most effective, the woman must be taught the Symptothermal Double-Check Method of Natural Family Planning by a qualified natural family planning teacher.

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