Understanding the Billings Method

Introduction

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

During the days leading up to ovulation, mucus generated by the cervix leaves the vagina when the woman is in the upright position and as she moves about. The mucus is observed at the vulva:

by the sensations of the vulva;
by visible mucus.

The recording of these observations is made at the end of each day.

Fertility is indicated by a changing sequence of observations.

Infertility is indicated by an unchanging sequence of observations.

These sequences follow the hormonal levels which control sperm survival and conception.

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	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28
Peak
possibly_fertile
wait
infertile
Sensation	wet	wet	wet	sticky	dry
Appearance

The Basic Infertile Pattern (Sequence)

Following menstruation the cervix is closed by a thick, dense plug of mucus which prevents the passage of sperm cells into the cervix.

There is nothing leaving the cervix and the vulva feels dry. Nothing is felt and nothing is seen. The recording of this observation is made with a brown bar (Figure 3).

Figure 3. Basic Infertile Pattern of dryness. There is no entry of sperm into the cervix because of a thick dense plug of mucus.

day	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28
Peak
possibly_fertile
wait
infertile
Sensation	wet	wet	wet	sticky	dry	dry	dry	dry	dry	dry
Appearance

The Basic Infertile Pattern (Sequence) is an unchanging sequence of observations and reflects cervical inactivity. In normal cycles it is recognized by:

Unchanging dryness (Figure 3), or
Dry vulva with a small amount of mucus seen and which is the same every day. Figure 4 illustrates a Basic Infertile Pattern of mucus. Three cycles are studied (4a, 4b, 4c ) in order to identify correctly the point of change of (i) sensation or (ii) the appearance of the mucus or both.

The ovaries are quiescent.

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

Following intercourse, the discharge of seminal fluid from the vagina may last for 24 hours and be felt as a wetness at the vulva.

Figure 4 (a) - (c) Basic Infertile Pattern (Séquence) of mucus 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)]. There is no entry of sperm into the cervix because of the plug of mucus.

day

4(a)

Peak

possibly_fertile

wait

infertile

Sensation

wet

sticky

dry

Appearance

slight mucus

4(b)

Peak

possibly_fertile

wait

infertile

Sensation

wet

sticky

dry

Appearance

slight mucus

4(c)

Peak

possibly_fertile

wait

infertile

Sensation

wet

sticky

dry

Appearance

slight mucus

Change

Figure 5 shows that the ovaries are now active and are producing oestrogen, which stimulates the cervix to activity. Fluid mucus is produced and this frees the plug so sperm can now enter the cervix (possibly fertile). A change in sensation from dry to no longer dry is now experienced and the mucus 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).

day	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28
Peak
possibly_fertile
wait
infertile
Sensation	wet	wet	wet	sticky	dry	dry	dry	dry	dry	dry	sticky
Appearance											cloudy

In the same way where there is a Basic Infertile Pattern of mucus (Figure 6) the ovary becomes active. The point of change is noted at the vulva where the sensation/mucus changes.

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

day	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28
Peak
possibly_fertile
wait
infertile
Sensation	wet	wet	wet	sticky	dry	dry	dry	dry	moist
Appearance					slight mucus	slight mucus	slight mucus	slight mucus	cloudy

Changing Sequence

Figure 7 shows the changing sequence of fertility. The ovary is producing increasing amounts of oestrogen. The mucus is changing to that giving rise to a wet, slippery sensation. Clear strings of mucus may be noticed. The maximum amount of mucus may diminish and a slippery sensation continue for a day or two. The last day of the slippery sensation is the most fertile day in the cycle and is termed the Peak and is associated with a heightened sensitivity and swelling of the vulva. Progesterone production occurs. The Peak is marked with a cross (x) on the bar.

Figure 7. The Peak, the last day of slippery sensation is marked with a (x) on the cream bar. See Figure 8 "Day 1 past Peak".

day	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28
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											cloudy			clear strings

The Peak is very close to the time of ovulation. Sperm cells can reach the outer part of the fallopian tube where the egg cell will be waiting to be fertilized (Figure 8).

The cervix is beginning to close (over the next 3 days) with the thick mucus under the influence of progesterone from the luteinized follicle (the corpus luteum). The progesterone has an influence on the mucus so that the woman appreciates the change in sensation at the vulva and she feels dry or sticky.

Figure 8. Day 1 past the Peak. Ovulation has occurred (or is imminent) and sensations at the vulva are no longer slippery, but either dry or sticky. They are recorded with a numbered brown or light brown bar. Thus the Peak is verified retrospectively.

day	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28
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											cloudy			clear strings

The Luteal Phase

Figure 9 illustrates the luteal phase of the cycle, where from the fourth day after the Peak (the last day of the slippery sensation at the vulva) the cervix is closed with a thick plug of mucus, preventing sperm cells from entering the cavity of the uterus.

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. By day 4 past the Peak the ovum has disintegrated. There is no entry of sperm into the cervix. Brown for dry or light brown for discharfe is now used in the record. The woman is infertile.

day	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
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											cloudy			clear strings								cloudy	cloudy	cloudy		cloudy

Menstruation (Figure 10) heralds the end of the cycle, usually 11 - 16 days after ovulation, and the start of the next cycle. The plug has left the cervix to allow the passage of blood.

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

Delayed Ovulation - the Extended Pre-ovulatory Phase and the Basic Infertile Pattern (Sequence)

Ovulation is often delayed at times of stress, during lactation and at the pre-menopause.

The Basic Infertile Pattern (Sequence) is an unchanging pattern, observed over a period of at least two weeks, of either:

no mucus (vulval dryness); or
an unchanging discharge at the vulva; or
a sequence of (1) and (2) when the discharge remains unchanged during 2 weeks of observation and is interrupted by dry days.

The Rules of the Billings Method

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.
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.

Understanding the Billings Method

Introduction

Records

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

The Basic Infertile Pattern (Sequence)

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

Change

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.

Changing Sequence

The Luteal Phase

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

Delayed Ovulation - the Extended Pre-ovulatory Phase and the Basic Infertile Pattern (Sequence)

The Rules of the Billings Method

The Pre-Peak Rules

The Peak Rule