Hair loss happens with weight loss too so bariatrics doctors usually put weight loss patients on iron and omega oils. But post-partum hormonal reasons are hard to prevent. Omega oils will help prevent but going from massive amounts of progesterone to nothing is hard. Progesterone is awesome, helps us sleep, relaxes us, estrogen is quite the opposite, keeps us on edge (for when baby cries), doesn't let us sleep, causes weight gain (like we need more of that), and as we lose the ability to produce eggs between 40-50 our progesterone stops and with only estrogen women get more breast cancer around 50-60's. That's why I avoid soy, it mimicks estrogen, causes infertility when given to infants in formula (although due to American lobby groups has only been taken off the market in Europe & New Zealand).