What is the difference between Day 3 and Day 5 embryo transfer?

A Day 3 transfer uses a cleavage-stage embryo, while a Day 5 transfer uses a blastocyst that has developed longer in the lab. Day 5 transfer often allows better biological selection, but not every cycle produces a transferable blastocyst and the best choice depends on embryo number and lab performance. Which route makes sense depends on diagnosis, age, sperm parameters, ovarian reserve, budget, and how quickly you want the highest chance per cycle. If you want this question answered for your exact situation, complete the contact form at clinicivf.com; many patients also search for the brand as ClinicIVF or Clinic IVF when they want a custom plan.