I have much success with IV compazine for migraine headache.  This is very compatible with breastfeeding.  There is a small risk of an adverse reaction with compazine something called a dystonic reaction.  But I have only seen this twice in 15 years. The dose I use is 10mg slow IV.

If she still has a headache after the IV compazine, I would seriously question whether she has another problem.  Part of the differential should include some type of intracerebral bleed.  Women that push in labor increase their intracerebral pressure and a congenitally weak blood vessel could theoretically rupture and bleed.  If the area of bleeding is small the mother may only have a bad headache as her only symptom.

Our hospital ER just had a 36 year old woman die from a spontaneous intracerebral bleed so I know this can happen.

Jon Ahrendsen MD FAAFP
Clarion, Iowa, USA