* Estrogen and headaches: Estrogen is the hormone that can affect a mother more when:
She has her monthly period.
She is taking an oral contraceptive pill.
She has a lower level of estrogen after childbirth.
She is on hormone replacement therapy.
* Oxytocin headache: The release of the hormone Oxytocin, can also trigger a headache. This hormone is released during the let down of milk and can also cause nausea during breastfeeding.This type of lactation headache will usually subside after a few minutes of breastfeeding.
* Plasma vasopressin is a hormone that is released during breastfeeding, which narrows the blood vessels, therefore, causing a headache.