Breastfeeding Contraception Method - Lactational Amenorrhea method (LAM)

Explain the physiological basis of the following.

Conception is unlikely to occur in a breastfeeding mother.

During lactation prolactin is required for the production of milk and oxytocin is required for
the ejection of milk form the ducts. Prolactin is secreted from the anterior pituitary but it is
usually under inhibition of prolactin inhibitory hormone secreted from the hypothalamus.
During suckling the PIH secretion is inhibited therefore prolactin secretion increases and milk
is produced in the alveoli. 

When sensory receptors in the nipple are stimulated the signal
travels in the spinal cord which stimulates the hypothalamus and thereby stimulates secretion
of oxytocin from the posterior pituitary. This leads to contraction of smooth muscles in the
lactiferous ducts and releases milk. This is called the let-down reflex. Prolactin produced
during milk production has an inhibitory effect on the hypothalamus and prevents pulsatile
GnRH release. This reduces FSH and LH secretion from the anterior pituitary. Due to low FSH
levels follicular development cannot occur properly. Therefore ovulation does not occur and
conception cannot occur as a result.