This is an FET cycle for us. We transferred one blastocyst -- just one, because we hope for a singleton.
At my first u/s (5w6d), we saw one heartbeat (thrilled!). The RE also spotted a \"secondary yolk sac.\" He said that the blast had definitely split, but that it wasn't clear that there would be a second heartbeat. He said it was early; I go back in a week for a follow-up u/s.
Does this ring familiar to anyone? What are the chances that the second, would-be identical twin, would have a delayed-in-appearing heartbeat?
Many thanks for any insights.