16/02/2026
Tüp bebek gebeliklerinde son adet tarihi gebelik yaşını yansıtır mı?
🏴 Does the last menstrual period reflect gestational age in IVF pregnancies?
➡️ In IVF treatments, ovulation does not occur within a natural cycle, and the timing of embryo transfer varies depending on the treatment protocol used. Therefore, calculating gestational age based on the actual last menstrual period (LMP) can sometimes be misleading.
🧐 So how should we respond when asked about the last menstrual period during pregnancy follow-ups?
➡️In a woman with regular cycles, ovulation typically occurs 14 days after the first day of menstruation, and the fertilized egg implants in the uterus approximately 5 days later.
🧮 In other words, we consider that a day-5 embryo implants around 19 days after the first day of the cycle:
📌 If a day-5 embryo was transferred:
Count back 19 days from the embryo transfer date to determine the adjusted last menstrual period.
📌 If a day-3 embryo was transferred:
Count back 17 days from the transfer date.
✅ Briefly, in IVF pregnancies, gestational age is sometimes calculated not according to the actual last menstrual period, but according to the developmental age of the embryo at transfer.
