Two things to look into: NutritionFacts.org by Dr Michael Greger looked at a study where women with terrible periods and PMS were given 1 tsp of seaweed (Bladderwrack). It helped reduce the circulating estrogen. Another video mentions 1–2 sheets of Nori per day to help reduce the incidence of breast cancer.

For PCOS, look into the supplement, Berberine. Lots of interesting studies.