Conception is the day that the sperm and the egg meet, so no, the day of transfer would not be the conception date. When you do a 3 day transfer, in a natural cycle the embryo would be in the Fallopian tubes. When you do a 5 day transfer, the blastocyst would be just arriving to the uterus in a natural cycle, so they say blastocyst transfers are better for this reason along with a few others.
Re: Date of conception/ embryo transfer
Conception is the day that the sperm and the egg meet, so no, the day of transfer would not be the conception date. When you do a 3 day transfer, in a natural cycle the embryo would be in the Fallopian tubes. When you do a 5 day transfer, the blastocyst would be just arriving to the uterus in a natural cycle, so they say blastocyst transfers are better for this reason along with a few others.