Era in a natural cycle

[winspert]

Hello again. I have a new question...Since i have no certain answers for that issue,i would like to ask you girls if you know. I have done era test and from the results we have found that my window opens one day earlier. That means that we must tranfer blastocysts at day 4....and that happens only on a cycle with frozen embryos. I did the era test on a natural cycle without taking any medication. No progesterone and estrogen. That happened with my previous doctor. Now i am with another doctor who claims that era test on a natural cycle has no value at all. That on a natural cycle the window opens naturally. And that is useless to take the era test on a natural cycle. Has anyone taken the era test on a natural cycle? I would like to inform you that my son came after we followed the results of the era test. I don't know if it was a coincidence or if it was a success