A recent study suggested that women who consumed higher amounts of iron (from plant not animal sources) had a lower rate of premenstrual symptoms.
Those who consumed more than 20 milligrams per day had about a 30% reduction in PMS symptoms compared with those who consumed less than the average amount (average intake of 9.4 milligrams per day).
This study was a re-analysis of data from one of the largest and best long term studies of women’s health, the Nurses’ Health Study II (1991-2001). Intakes of sodium, magnesium, and manganese were unrelated to PMS risk, and intake of zinc was very slightly linked to a lower risk of PMS.
UptoDate reviewed data on different supplements (you can click here for a well written discussion about iron for treatment of anemia).
They concluded that different forms of iron (gluconate, sulfate, etcetera) aren’t much different in terms of tolerability (the main adverse effect is upset stomach), provided that you correct for the amount of elemental iron that each 
supplement contains. The larger the binding ion is the less iron there will be per milligram of the supplement. For instance, iron bis-glycinate has a relatively small amount of elemental iron (27 mg per pill) because bis-glycinate is a very large molecule, whereas a typical pill of iron sulfate (325 mg total) contains 65 mg of iron per pill. So a pill of iron bis-glycinate would be better tolerated than a pill of iron sulfate, but just because it has less iron in it.
Unfortunately, timed release forms aren’t a good idea because iron is best absorbed in the upper part of the GI system. Also, for the absolutely best results (perhaps not important for this purpose) you should take iron with a slightly acid substance (a small dose of vitamin C or a glass of orange juice).
For those who want more information about iron supplements you might want to buy a subscription to ConsumerLab.com which just updated its ratings of several different iron supplements.
The reference for this study is –
Am J Epidemiol. 2013 Feb 26. Intake of Selected Minerals and Risk of Premenstrual Syndrome. Chocano-Bedoya PO, Manson JE, Hankinson SE, Johnson SR, Chasan-Taber L, Ronnenberg AG, Bigelow C, Bertone-Johnson ER.