Production of breast milk is controlled by the hormone prolactin which is produced in the anterior pituitary gland. During pregnancy the levels of prolactin rise 35-fold* over pre-pregnancy levels. Following birth the levels of prolactin begin to fall. The rate at which the prolactin falls relates to the frequency of suckling of the baby at the breast. If the baby suckles frequently, deriving all nourishment from the breast, prolactin levels will usually remain high. As the length of time between feeds increases and the amount of milk consumed decreases (as other foods are introduced) the levels of prolactin will fall, spiking up at each feed and dropping between feeds. [* Study by S Biswas and CH Rodeck in BJOG: An International Journal of Obstetrics and Gynaecology , Vol 83 Issue 9, pages 683-687.]

The pituitary gland (posterior) also produces the hormone oxytocin which controls the “let down” reflex and the flow of milk when the baby suckles at the breast. Production of prolactin and oxytocin inhibit the production of follicle stimulating hormone (FSH) and luteinizing hormone (LH) which are necessary for fertility. Hence, in most women, fertility does not return for some time – weeks, months, or longer than a year – while a mother is breastfeeding her infant. Every mother and baby duo is unique and the time of return of fertility cannot be predicted. A woman who knows the Billings Ovulation Method® will however, recognise her infertility and the changes that will herald the return of fertility.

Charting should commence 3 weeks after birth or as the lochia diminishes. Many women will chart a continuous pattern of dryness which is readily recognized as her Basic Infertile Pattern (BIP) and the couple can resume intercourse applying the Early Day Rule 2 – intercourse available on alternate evenings of the BIP of dryness. Another woman may chart a continuous pattern of discharge, for example, an unchanging milky discharge, with a sensation of dampness or stickiness. If there is no bleeding and the pattern is unchanging for two weeks, infertility can be recognized and the Early Day Rules applied. Perhaps the pattern may reveal some dry days interspersed by some days of unchanging discharge. This combined pattern also indicates infertility and the Early Day Rules can be applied. Each woman becomes confident in recognising her own unique pattern indicating infertility.

Whenever a change is noticed, whether it be a change in the sensation felt at the vulva, a change in visible discharge, or any bleeding or spotting, the couple should apply Early Day Rule 3 – wait and see what happens. If the BIP, returns a count of 3 days of this BIP is required before the couple resumes intercourse using Early Day Rule 2.

Over time, as the baby grows and the demand for breast milk changes, the mother may notice a change in her pattern. Where previously she had an unchanging pattern, whether she has a BIP of dry, a BIP of discharge or a combined BIP, she may now have days which are different. If the couple is not yet ready for another pregnancy they will apply Early Day Rule 3 to wait and see what happens. If over two weeks of charting without intercourse and without any bleeding it becomes obvious that a new unchanging pattern has emerged, then the couple can once again resume intercourse on alternate evenings, following Early Day Rule 2. For example, the Basic Infertile Pattern may have changed from continuous dryness, to a continuous pattern of slight discharge; or the continuous discharge may have changed to a different description which is again unchanging; or the combination pattern may have changed to a different combination of descriptions which are unchanging over two weeks. In all of these examples a new BIP can be established.

Infertility can be present for weeks or many months after birth, however some women who are successfully fully breastfeeding their baby may have a return to fertility as early as six weeks post birth. These women will recognize a changing pattern leading to slippery and the recognition of Peak. This may occur soon after the lochia finishes.

However most women will experience a longer time of infertility. If a woman breastfeeds her baby for many months she may identify more than one change in her Basic Infertile Pattern. These changes are often related to changes in the baby’s feeding pattern, e.g. sleeping longer at night, introduction of solid foods, illness of mother or baby, etc. If the intention is to avoid pregnancy, each time there is a change the couple should wait without intercourse until either the recognised BIP returns or, after two weeks of charting, the pattern reveals a new BIP. Eventually the levels of prolactin will fall to the point where the pituitary may begin to also produce some FSH. The woman will notice changes to her pattern as the cervix responds to changing levels of oestrogen produced by developing follicles. There may be patches of mucus and perhaps some bleeding or spotting which require the application of Early Day Rule 3. It may still be some weeks or even months before she recognizes a Peak, indicating ovulation, but it should be remembered that the first ovulation can occur before any bleeding. Once ovulation has occurred, if there is no conception, menstruation will follow. Initially the luteal phase may be short indicating that fertility has not yet returned, but over the following weeks normal fertile cycles will resume.

Professor James B Brown has discussed these ovarian variants in his writings on the Continuum of Ovarian Activity in his booklet: Studies on Human Reproduction. He described the return to fertility through the various ovarian variants from amenorrhoea to follicular development with or without an LH surge; through deficiency in the LH mechanism resulting in Luteinised Unruptured Follicles; poor corpus luteum formation with deficient or short luteal phases; up to the fully fertile ovulatory cycle. The return to fertility following breastfeeding may not proceed immediately from a very long pre-ovulatory phase to fully fertile cycles. More commonly a woman may experience a number of variants of the continuum before returning to fully ovulatory cycles, as described by Professor Brown.**

The chart will reveal these variants as changes from the Basic Infertile Pattern and management of these variants is covered by the Rules of the Billings Ovulation Method®. The breastfeeding or weaning mother may experience a number of occasions when the Early Day Rule 3 is applied without recognition of a Peak. Eventually she will recognise Peak indicating to her that she has finally ovulated and the Peak Rule can be applied.

When a Peak has been recognized, the subsequent bleeding is menstruation. It is important to now reestablish the Basic Infertile Pattern. The woman is now in a different situation – previously she was in a long pre-ovulatory phase which may have lasted many months; now she is returning to ovulatory cycles. If cycles are shorter than 35 days there can be only ONE Basic Infertile Pattern, the description for which may be different from any BIP she recognized before the first Peak.

The usual guidelines apply for establishing a Basic Infertile Pattern. Dry days are immediately recognized as infertile. Any unchanging pattern of discharge must be observed over three cycles of less than 35 days before it can be verified as a Basic Infertile Pattern and the Early Day Rules applied. A combination Basic Infertile Pattern is not possible in a cycle of less than 35 days. If ovulation is delayed, 2 weeks of charting without intercourse will identify an unchanging pattern and a Basic Infertile Pattern of discharge or a combined Basic Infertile Pattern can be identified. The Peak Rule can be used as soon as a Peak is recognized.

The Billings Ovulation Method® teaches a woman to recognize fertility and infertility on a day by day basis whether she is ovulating regularly or not. By encouraging the breastfeeding woman to chart her symptoms using the Billings Ovulation Method® early in the breastfeeding experience, she gains confidence in her ability to recognise infertility and the changes which herald potential fertility when they occur. The couple is able to confidently use only the Early Day Rules until the first recognition of Peak, regardless of how long this takes. The breastfeeding mother should be encouraged to keep in regular contact with her Billings Ovulation Method® teacher so that she can be supported during times of change in her pattern.