Understanding the Billings Method

Introduction

The anatomy of the female reproductive system is illustrated in Figure 1.

At fertile times, oestrogen stimulates the crypts of the cervix to secrete particular types of mucus that control sperm survival and conception. This mucus leaves the vagina when the woman is up and about. The mucus is observed at the vulva:

  1. by sensations;

  2. by a visible discharge.

A changing sequence of observations indicates fertility.

An unchanging sequence of observations indicates infertility.

Reproductive Organs

Figure 1. The female reproductive organs.

Records

A daily record is made in the evening of the most fertile characteristics observed throughout the day. There must be no internal examinations made as these will be confusing. For the first few weeks observations are made without any genital contact so that they will not be confused by any secretions due to intercourse or contact. Keyword descriptors for the daily observation are entered.

The sequence of observations form a bar chart. The height of each bar indicates the level of fertility.

The legends for the bar chart are given on the page Charts - The Visual Record.

Menstruation is recorded with a red bar(Figure 2).

(Heavy bleeding obscures mucus when ovulation is early.)

Rule 1: Avoid intercourse on days of heavy bleeding during menstruation.

Figure 2. Menstruation, indicated by a red bar.

day

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Peak

 

possibly_fertile

 

wait

 

 

 

 

 

 

infertile

 

 

 

 

 

 

Sensation

wet

wet

wet

sticky

dry

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Appearance

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The Basic Infertile Pattern (Sequence)

The cervix is closed by type G mucus after menstruation. Type G mucus prevents the passage of sperm cells into the cervix.

The vulva feels dry. Nothing is seen. The recording of this observation is made with a brown bar (Figure 3).

Figure 3. Dry Basic Infertile Pattern: Type G mucus prevents the passage of sperm cells into the cervix.

day

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Peak

 

possibly_fertile

 

wait

 

 

 

 

 

infertile

 

 

 

 

 

 

 

 

 

 

 

Sensation

wet

wet

wet

sticky

dry

dry

dry

dry

dry

dry

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Appearance

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

In normal cycles the Basic Infertile Pattern (Sequence) is recognized by:

  1. Constant dryness (Figure 3), or

  2. An unchanging discharge that produces the same sensation and appearance day after day. Figure 4 illustrates this type of Basic Infertile Pattern of discharge. Three cycles are required (4a, 4b, 4c ) in order to establish a constant unchanging sequence that precedes a change in (i) sensation or (ii) the appearance of the discharge, or both.

Rule 2: Alternate evenings are available for intercourse when these days have been recognized as infertile (Basic Infertile Pattern).

Seminal fluid resulting from sexual intercourse discharges from the vagina for up to 24 hours and may cause a wet sensation at the vulva.

Figure 4 (a) - (c) Basic Infertile Pattern (Sequence) of discharge remains the same day after day, cycle after cycle [initially recorded with a cream bar (4a, 4b) but then recorded with a light brown bar when the sequence is seen to be unchanging (4c)]. Sperm cannot enter the cervix because of the type G mucus plug.

 

day

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4(a)

Peak

 

possibly_fertile

 

 

 

 

 

 

wait

 

 

 

 

 

 

 

 

 

infertile

 

 

 

 

 

 

 

 

 

Sensation

wet

wet

wet

sticky

dry

dry

dry

moist

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Appearance

 

 

 

 

slight mucus

slight mucus

slight mucus

opaque

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

4(b)

Peak

 

possibly_fertile

 

 

 

 

 

 

 

 

wait

 

 

 

 

 

 

 

 

 

 

 

 

infertile

 

 

 

 

 

 

 

 

 

 

 

 

Sensation

wet

wet

wet

sticky

dry

dry

dry

dry

dry

dry

damp

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Appearance

 

 

 

 

 

slight mucus

slight mucus

slight mucus

slight mucus

slight mucus

opaque

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

4(c)

Peak

 

possibly_fertile

 

 

 

wait

 

 

 

 

 

 

 

 

 

 

infertile

 

 

 

 

 

 

 

 

 

 

Sensation

wet

wet

wet

sticky

dry

dry

dry

dry

moist

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Appearance

 

 

 

 

slight mucus

slight mucus

slight mucus

slight mucus

opaque

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Change

Figure 5 shows that the ovaries are active. They produce oestrogen which activates the cervix into producing fluid mucus and thus giving passage to sperm (possibly fertile). A change in sensation from dry to no longer dry is now experienced and a discharge may be seen. This is recorded with a cream bar (possibly fertile).

Rule 3: Avoid intercourse on any day of discharge or bleeding which interrupts the Basic Infertile Pattern (Sequence). Allow 3 days of Basic Infertile Pattern (Sequence) afterwards before intercourse is resumed on the fourth evening. Rule 2 continues.

Figure 5. Point of change in sensation at the vulva from dry (brown bar) to no longer dry (cream bar). Sperm are now able to enter the cervix (possibly fertile).

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Peak

 

possibly_fertile

 

 

 

wait

 

 

 

 

 

 

 

infertile

 

 

 

 

 

 

 

 

 

 

 

 

Sensation

wet

wet

wet

sticky

dry

dry

dry

dry

dry

dry

sticky

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Appearance

 

 

 

 

 

 

 

 

 

 

opaque

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Similarly when there is a Basic Infertile Pattern of discharge (Figure 6) the point of change is noted by a change in sensation/discharge.

Figure 6. Point of change in sensation (moist) at the vulva from a Basic Infertile Pattern (Sequence) (light brown bar) to discharge which looks opaque (cream bar). Sperm are now able to enter the cervix (possibly fertile).

day

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Peak

 

possibly_fertile

 

 

 

wait

 

 

 

 

 

 

 

infertile

 

 

 

 

 

 

 

 

 

 

Sensation

wet

wet

wet

sticky

dry

dry

dry

dry

moist

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Appearance

 

 

 

 

slight mucus

slight mucus

slight mucus

slight mucus

opaque

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Changing Sequence

Figure 7 shows the changing sequence of symptoms in a fertile phase. The ovary produces increasing amounts of oestrogen. The mucus becomes thinner, clearer, more profuse and then merely slippery. At the most fertile time the vulva will feel wet and slippery, even if there is too little discharge to see. The convention is to mark the Peak day with an (x) on the bar.

Figure 7. The Peak is the last day of slippery sensation. See Figure 8 "Day 1 past Peak".

day

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Peak

 

X

 

possibly_fertile

 

 

 

 

 

 

 

1

 

wait

 

 

 

 

 

 

 

 

 

 

 

 

 

infertile

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Sensation

wet

wet

wet

sticky

dry

dry

dry

dry

dry

dry

sticky

wet

slippery

slippery

slippery

slippery

sticky

 

 

 

 

 

 

 

 

 

 

 

Appearance

 

 

 

 

 

 

 

 

 

 

opaque

 

 

clear strings

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The Peak is very close to the time of ovulation. Figure 8 depicts sperm cells in the fallopian tube. Fertilisation of the egg occurs in the part of the fallopian tube close to the ovary.

The ruptured follicle which contained the egg (corpus luteum) secretes progesterone. This causes the cervix to produce type G mucus again. The cervix will be closed by a mucus plug after three days. The change in the mucus and associated activity of the Pockets of Shaw cause an abrupt change in both the sensation at the vulva (no longer wet or slippery) and the appearanace of any discharge.

Figure 8. Day 1 past the Peak. Ovulation has occurred (or is imminent) and sensations at the vulva are no longer wet or slippery. Thus the Peak is verified retrospectively. This day is recorded with a numbered brown or light brown bar.

day

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Peak

 

X

 

possibly_fertile

 

 

 

 

 

 

 

1

 

wait

 

 

 

 

 

 

 

 

 

 

 

 

 

infertile

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Sensation

wet

wet

wet

sticky

dry

dry

dry

dry

dry

dry

sticky

wet

slippery

slippery

slippery

slippery

dry

 

 

 

 

 

 

 

 

 

 

 

Appearance

 

 

 

 

 

 

 

 

 

 

opaque

 

 

clear strings

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The Luteal Phase

If the egg is not fertalised there is a period of about 14 days after ovulation (the luteal phase) before menstruation begins (Figure 9). The cervix is closed by type G mucus. Rule 4 allows for the possibility that ovulation is delayed after the Peak day.

Rule 4 (the Peak Rule). From the beginning of the fourth day following the Peak until the end of the cycle intercourse is available every day at any time

Figure 9. The woman is infertile from day 4 past the Peak . Brown for dry or light brown for discharge is now used in the bar chart.

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Peak

 

X

 

possibly_fertile

 

 

 

 

 

 

 

1

2

3

 

wait

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

infertile

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Sensation

wet

wet

wet

sticky

dry

dry

dry

dry

dry

dry

sticky

wet

slippery

slippery

slippery

slippery

dry

sticky

sticky

sticky

dry

dry

dry

dry

dry

moist

dry

dry

dry

dry

Appearance

 

 

 

 

 

 

 

 

 

 

opaque

 

 

clear strings

 

 

 

 

 

 

 

opaque

opaque

opaque

 

opaque

 

 

 

 

Menstruation (Figure 10) is the shedding of the lining of the uterus as a result of decline in the levels of oestrogen and progesterone. The mucus plug dissipates allowing the flow of blood.

Figure 10. Menstruation which usually occurs 11-16 days after ovulation.

Delayed Ovulation and the Basic Infertile Pattern(Sequence)

Ovulation is often delayed at times of stress, during lactation and at the pre-menopause. The BIP is then an unchanging sequence observed for 2 weeks.

In addition to the types of The Basic Infertile Pattern (Sequence) already identified, it can be a sequence of dryness or unchanging discharge interleaved with another unchanging sensation/discharge observed over 2 weeks.

The Rules of the Billings Method

  1. For the Achievement of Pregnancy:
    Apply Rules 1,2, and 3. This enables the change to the fertile pattern of mucus to be recognized. Then postpone intercourse until slippery mucus occurs. The next few days are the most fertile. Therefore intercourse should occur while slippery mucus is obvious and for one or two days past the Peak.

  2. For the Postponement of Pregnancy:

    The Pre-Peak Rules

    Rule 1: Avoid intercourse on days of heavy bleeding during menstruation.

    Rule 2: Alternate evenings are available for intercourse when these days have been recognized as infertile. (Basic Infertile Pattern)

    Rule 3: Avoid intercourse on any day of discharge or bleeding which interrupts the Basic Infertile Pattern. Allow 3 days of Basic Infertile Pattern afterwards before intercourse is resumed on the fourth evening. Rule 2 continues.

    The Peak Rule

    Rule 4. From the beginning of the fourth day following the Peak until the end of the cycle intercourse is available every day at any time.