Supplements for "women's things"

[Plibble]

A friend of mine has a long menstrual cycle (38-42 days) since having her second child 10 months ago. She stopped breastfeeding 4 months ago. It is starting to worry her a little because she and her husband are thinking of trying for number 3 and will only get one shot every month and a half or more.
Is there any supplement or herb that is recommended for regulating the menstrual cycle and perhaps bringing it into line with average lengths?
TIA

I don't know much about supplements, but accupuncture could be helpful. I have had a couple of sessions of accupuncture a year for several years, which helps me with painful periods, and my accunpuncturist reckons that she has a good success rate for fertility problems: I have to say, dd was conceived within a couple of months of my last treatments with her.

Thanks Roskva. I'll suggest that to her.