Run tests via in vitro fertilization
Use multiple women at multiple fertility clinics to make sure the process works in at least a few of them. You can use any woman who is just about to ovulate but it would be best to use women who were already in the process of doing IVF and were scheduled to have their eggs harvested anyway.
It takes 5-6 days after fertilization in a petri dish for an embryo to "hatch." This does not tell you if the embryo can be successfully implanted in a "new" uterus and if it will gestate. But it will at least tell you that conception is possible (or not).
Coordinate these tests worldwide, on hundreds, or thousands of eggs. Use eggs and sperm from women and men who are both transformed. Also run tests on transformed women with human men and human women with transformed men.
Do sperm analysis
In transformed men you would also do sperm analyses. Hundreds/thousands of them. Put the results online. If the transformed men are not producing viable appearing sperm, you've more or less answered your question, though you still want to test it with live eggs either way.
Try frozen embryo transfer
When people create embryos via IVF, it's common to freeze "extra" ones you are not implanting that cycle. Some people later donate these embryos when they no longer need them, which means they're available to women who wish to get pregnant using them.
When you implant an embryo, it's done a few days after ovulation, which means that pregnancy detection can be done sooner than if you're timing it from a natural conception, which must happen the day of or a few days before ovulation. Chances are good that you could know that implantation was successful within a week of doing the procedure.
These embryos of course will be fully human and successful implantation will not tell you anything about conception in transformed humans. But they will give you information about a transformed uterus, if it is capable of accepting an embryo and starting the gestation process.
Like with the IVF tests, use women who were already about to be implanted but who are now transformed. It doesn't matter if they're using their own stored embryos or donated ones.
Finding fertility clinics
In the US alone, "there are about 480 U.S. fertility clinics, 100+ sperm banks, an unknown number of egg donors, and 1,700 reproductive endocrinologists." A large number of them will have some women who are just about to undergo egg harvesting or embryo implantation. You may be able to include more women in the trials if necessary, especially if they're women who were not doing IFV or embryo transfers but were trying to get pregnant and carefully monitoring their cycles (with ovulation prediction) and taking hormones (progesterone after ovulation being very important here).
Use every country with fertility clinics/doctors and put all the information on a single site on the internet (like StackExchange). Allow people access to the data so it gets analyzed in hours, not days. Crowdsourcing, reports on Twitter, whatever it takes.