Development of IVF/ICSI Children Born From Different Endometrial Preparation Protocols

Development of IVF/ICSI Children Born From Frozen Embryo Transfer Cycles With Different Endometrial Preparation Protocols: Follow-up of a Randomized Controlled Trial

The efficacy and safety of endometrial preparation regimens remain controversial. In the most recent meta-analysis, using natural and modified natural cycle protocol to prepare the endometrium in frozen embryo transfer resulted in higher live birth rates. In addition, the natural cycle reduces the risk of gestational hypertension, postpartum haemorrhage, and extremely preterm delivery compared with regimens using exogenous hormones.

Because there are many physiological and endocrinal differences in the frozen embryo transfer cycle with different endometrial preparation protocols, the development of children born from these regimens has received much attention. For example, there is a complete absence of the corpus luteum during the cycle of exogenous hormone administration. Or in the modified natural cycle, the pharmacokinetics is not entirely the same as the natural physiology when using an additional ovulatory injection with hCG. To date, there have been no longitudinal follow-up studies that evaluated and compared the long-term development of IVF/ICSI children born from frozen embryo transfer with different endometrial preparation protocols.

Thus, the investigators conduct a follow-up of our RCT to investigate the IVF/ICSI children born from frozen embryo transfer with different endometrial preparation protocols to give strong evidence about the safety of the three most common endometrial preparation protocols in women undergoing frozen embryo transfer.

Developing further from a previous randomized controlled clinical trial (MONART study - NCT04804020), the investigators decided to assess the physical, mental, and motor development of children up to 24 months after birth, with the aim of providing additional information on the safety of these regimens on the long-term health of the IVF/ICSI children.

Inclusion Criteria:

• All live IVF/ICSI babies born from frozen embryo transfer following the natural cycle, modified natural cycle, and artificial cycle from MONART study
• Parents agree to participate in the study.

Exclusion Criteria:

• Babies died under or at 24 months