4th Day Intercourse

Dr. Evelyn L. Billings
Ovulation Method Research and Reference Centre of Australia

Peak Rule: For the avoidance of conception, intercourse is available from the beginning of the fourth day after the Peak, and thereafter at any time until menstruation begins.

Q. When does the day begin?

A. After midnight on the third day past the Peak, that is the beginning of the fourth day.

Correct identification of the Peak is the key to the successful application of the Peak Rule for the avoidance of pregnancy. Scientific studies show clearly a correlation between the Peak and ovulation (a) on the Peak; (b) day 1; (c) rarely on day 2. As the ovum lives less than 24 hours and probably not more than 12 hours, it will have disintegrated by the beginning of the fourth day. All scientific calculations are made from midnight to midnight.

The Peak is the last day of mucus with fertile characteristics. That includes the sensation at the vulva caused by:

(a) the presence of mucus (slippery due to P mucus as shown by Odeblad); and

(b) the soft swelling of the vulval tissue (due to Iymphatic oedema as explained by Odeblad) accompanying the developing follicle and therefore closely associated with the event of ovulation itself. This is a very valuable sign and needs to be pointed out to the woman as it may not be immediately obvious. These signs must have disappeared in order to have identified the Peak correctly.

A woman may describe wetness around about this time and the teacher must find out what she means by "wetness". She may mean "not dry", or "sticky" or even "slippery" and the distinction is very important. It is wrong to regard the last day of stretchy mucus or the most mucus as the Peak. This is a visual sign. The mucus is often copious and sometimes tinged with blood. The stretch is produced by a combination of L and S mucus and occurs 1 or 2 days before the Peak when the P mucus has caused the dissolving of the strings and produced a very lubricative sensation at the vulva Ñ often with nothing left to see. The quantity of mucus which women experience is extremely variable and depends on the cervical response to the hormonal patterns.

If a teacher feels that the woman is not confident about her Peak, she will clarify the teaching on the recognition of the Peak and the Peak Rule, explaining simply the scientific proof, thereby giving her confidence in her own observations. If the Peak is indeed indefinite and until the Peak has been clearly defined, the Early Day Rules should be applied until a definite Peak is recognized. This becomes very important in the approach to the menopause, after stopping chemical contraception, in stress cycles, during breast-feeding and any other circumstances when ovulation has been delayed.

The Early Day Rule of 'wait and see, 1,2,3' with intercourse on the fourth night is correct for a different reason. We are concerned with the presence of mucus before ovulation and therefore the survival of healthy sperm. After ovulation we are concerned with the life of the ovum.

In the early part of the cycle the woman needs to be up and walking in order to be sure that no mucus has left the cervix. In the 'wait and see, 1,2,3' the third day has not finished until midnight. The next day must be judged to be infertile after the woman is up again and walking about until the evening of the fourth day.

The hormonal pattern of the Peak is constant for all ovulations. The Peak is closely related to the abrupt fall in oestrogen plus the rise (just before ovulation) of progesterone. The hormonal levels vary from woman to woman and cycle to cycle but the pattern is constant. This makes a woman's observations of her own Peak an individual thing with which she becomes very familiar.

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