STM During Breastfeeding

HOW LONG DOES POST- PARTUM INFERTILITY LAST?

The duration of natural infertility after childbirth does vary from woman to woman.  This is directly related to whether the mother fully breastfeeds, partially breastfeeds, bottle feeds, or had a stillbirth.

HOW DOES THIS HAPPEN?

During pregnancy high levels of oestrogen and progesterone prevented the release of the follicle stimulating hormone (FSH) and the luteinising hormone (LH) which are needed to ripen an egg.  Prolactin, a hormone directly related to the production of milk for the nourishment of the baby, neutralises FSH and LH thus inhibiting ovulation.  

These physiological blocks create a ‘natural’ infertility which continues into the early weeks after child birth and may last for the duration of breastfeeding 

HOW DOES BREASTFEEDING AFFECT FERTILITY?

The baby’s suckling during breastfeeding stimulates the production of prolactin which cuts off the production of FSH and LH needed for ovulation to occur.  This means that the more often the baby feeds the less chance there is of fertility returning.  The majority of breastfeeding mothers can rely on the Lactational Amenorrhoea Method (LAM) to maintain their infertile state and thus avoid a pregnancy however some will need to use another method during breastfeeding stage – Sympto –thermal NFP

PARTIAL BREASTFEEDING

Mothers who choose to use supplementary formula feeds along with partial breastfeeds may return to fertility quickly.  Baby is not relying on the breast for sustenance so is not sucking as much as a fully breastfeeding baby.  That means that the FSH and LH can activate ovulation

Mothers who are partially breastfeeding need to chart their unchanging infertile mucus pattern until the BIP is established.  They must consider themselves in the pre-ovulatory phase until ovulation is confirmed by the temperature shift prior to menstruation.  Follow the STM rules for intercourse. 

Most mothers who have breastfeed for 1 month or less after giving birth will be infertile for 4 weeks following birth.  Ovulation may occur as early as the 5th week.  Menstruation commonly occurs at the 7th/8th week.  Charting of NFP symptoms needs to start in the 4th week.  

WHAT ABOUT THOSE WHO DO NOT BREASTFEED? 

Within the first few weeks after delivery the concentration of the hormones oestrogen and progesterone in the mother’s bloodstream fall. 

If suckling does not occur the physiological blocks to ovulation are removed and natural infertility ends.  Studies show that the return to fertility varies - some women ovulate within 6 weeks of delivery others from 3 - 5 months.

WHAT CAN THEY DO?

Mothers who bottle feed or who don’t breastfeed need to be aware of the return of their fertility about 3 - 4 weeks after giving birth.  It is necessary for these women to observe and chart their fertility symptoms if they wish to avoid a pregnancy.

 

DETECTING SIGNS OF RETURNING FERTILITY

BASAL BODY TEMPERATURE (BBT)

As a woman may not be able to observe mucus until the lochia discharge ceases, the first sign she may be able to detect is the shift in basal body temperature (BBT).  It is necessary, then, to begin charting the BBT 14 days post-partum.  At first, the temperature may be up and down but it will soon settle and when a definite shift occurs a woman can be sure her fertility has returned.

THE MUCUS SYMPTOM

As soon as the lochia discharge stops the mucus symptom can be observed. The basic infertile pattern (BIP) needs to be established and the pre-ovulatory rules apply.

 

WARNING   

Any change from dryness to mucus or from one type of mucus to another should be interpreted as a sign of returning fertility. The couple need to abstain until the situation is clear.

MOTHERS WHO BOTTLEFEED 

Fertility returns quickly to postpartum mothers who do not breastfeed.  These women can readily chart normal ovulatory cycles.  They will notice, however, that in the first cycles after childbirth the luteal phase (from ovulation to the next period) tends to be shorter. This means that the whole cycle is shorter than was usual prior to pregnancy.

RETURNING FERTILITY 

Unless a woman is breastfeeding on demand, her fertility returns around 6 weeks after childbirth. Ovulation may occur as early as the 4th week and in 50% of women ovulation occurs prior to the 1st post partum menstrual period.  The period can occur between 6-8 weeks but may be delayed up to 10 weeks.

Women using natural family planning need to chart from 3-4 weeks post partum.

 

Reference

Gross, G.A., (1984) Breast feeding and the Return to Fertility, Int. Review of NFP Vol viii No. 2 Summer. MJA 1983

 

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