I took it when trying conceive my 3rd son as I was having short luetal phase, luckily for me it worked in the first cycle or it may have been a conicindence but I had been trying the previous couple of months with no success.

The advice I have heard is if you do fall pregnant you don't stop taking it cold turkery as it will drop your progesterone levels and could cause a miscarriage, it is better to slowly reduce your dosage down to nothing. I probably only kept taking it for a couple of weeks after I found out I was pregnant.

I guess if you had hormonal issues it may be recommended for the duration of the pregnancy if it were required but I think I would speak to a naturopath about that one.