Why Frozen Embryo Transfers Work Better than Fresh
Patient: Dr Malpani, I’ve heard about both fresh and frozen embryo transfers. What’s the difference between the two?
Dr. Malpani: Great question! Earlier, all embryo transfers were fresh — we would stimulate your ovaries, collect your eggs, create embryos, and transfer them in the same cycle.
Patient: That sounds efficient. So why not continue with fresh transfers?
Dr. Malpani: The problem is that during fresh cycles, your body is flooded with hormones to grow multiple eggs. This often raises estrogen levels too high, which can reduce the uterus’s ability to accept the embryo — what we call endometrial receptivity.
Patient: So even if the embryos are good, they may not implant?
Dr. Malpani: Exactly. In a natural cycle, your oestrogen level is around 200–300, which is perfect for one embryo. But in an IVF cycle with 10–15 follicles, estrogen can skyrocket to over 2000–3000. This disrupts the natural balance, making the uterus less receptive.
Patient: That’s surprising. So what do you do differently now?
Dr. Malpani: Now, we use a two-step approach. First, we stimulate the ovaries and create embryos — but instead of transferring them right away, we freeze them using a method called vitrification.
Patient: And frozen embryos survive the freezing process?
Dr. Malpani: Yes — if the clinic has a good lab, the thaw survival rate is nearly 100%. In the next cycle, we focus only on preparing the uterus using estrogen, making it ideal for implantation.
Patient: Does this two-step method improve success rates?
Dr. Malpani: Absolutely. It allows us to separate egg stimulation from embryo transfer, so each step gets the ideal conditions. That’s why frozen embryo transfers now have better outcomes in most cases.
Patient: Thank you, Dr Malpani. This makes so much sense. I was confused before but now feel much more confident.