Yes, by supplements, I mean the medication she was prescribed. All
IVF cycles use progesterone (and most also
estrogen). Like AnnieBrooke said, as long as she continues on the medication, there's really no need to worry about the levels being a factor.
Also, keep in mind that since the progesterone levels, which are the most important here, are produced by the medication, they can fluctuate a little throughout the day.