Day 3 vs Day 5 Embryo Transfer: Which is Better?

1. Quantity and Quality of Eggs: Obtaining a larger number of eggs provides more embryos to potentially reach Day 5. High-quality eggs typically develop into high-quality embryos, thereby increasing the likelihood of successful development by Day 5.

2. Developmental Potential of Embryos: Only embryos with sufficient potential can successfully develop to Day 5. The daily development status of embryos, including growth rate and morphology score, is crucial in assessing their potential.

3. Pre-Implantation Screening Techniques: Advances in medical technology, particularly in genetic screening techniques such as PGT-A (formerly known as PGS, Preimplantation Genetic Screening), help identify embryos with normal chromosomes, which is crucial for improving the success rate of implantation.

Further Reading: 

Is PGS Genetic Screening Necessary for IVF Babies?

Does PGS (PGT-A) Harm Embryos? How is it Conducted?

Maximizing IVF Success: Day 5 Blastocyst Transfer with PGT-A Genetic Screening

In the field of IVF, selecting the best embryo for transfer is key to maximizing success rates. With advancements in reproductive technology, transferring blastocysts on Day 5 along with PGT-A genetic screening has become the preferred strategy for improving IVF success rates, ensuring the selection of the healthiest embryos for implantation.

By Day 5, embryos have developed into blastocysts with distinct structures, including inner cell mass and trophoblast cells. This developmental stage allows for sampling from the trophoblast layer for PGT-A, a critical technique for screening embryo chromosomal abnormalities. Through PGT-A, embryos with normal chromosomes can be effectively identified, significantly increasing the success rate of pregnancy and reducing the risk of miscarriage.

In contrast, embryos on Day 3 have not yet reached a stage suitable for effective genetic screening. At this stage, embryos are primarily assessed based on morphological features, which may not fully reflect their chromosomal status. Therefore, while Day 3 embryo transfer offers the opportunity for early implantation, it does not allow for PGT-A screening and may increase the risk of failure due to chromosomal abnormalities. Therefore, it is recommended that even young couples consider striving to cultivate embryos until Day 5 for blastocyst transfer along with PGT-A genetic screening. This not only increases the overall success rate of IVF but also minimizes the risk of chromosomal abnormalities to the greatest extent possible.

Characteristics of Day 3 Embryo Transfer

• Early Implantation: Embryos typically reach the 6 to 8-cell stage on the third day, allowing for earlier implantation.

• Lack of Genetic Screening: At this stage, embryos have not developed enough for PGT-A genetic screening, making it impossible to identify embryos with chromosomal abnormalities.

• Higher Risk of Multiple Pregnancies: Due to lower implantation rates, multiple embryos may need to be transferred to increase the chances of success, thus increasing the likelihood of multiple pregnancies.

• Suitable Conditions: Suitable for cases with fewer available eggs or embryos of insufficient quality to extend cultivation to the fifth day.

Characteristics of Day 5 Embryo Transfer

• Delayed Implantation: Embryos reach the blastocyst stage on the fifth day, exhibiting more mature development and a more complete structure.

• Genetic Screening: PGT-A screening can be performed to identify embryos with normal chromosomes, significantly increasing the success rate of pregnancy and reducing the risk of miscarriage.

• Reduced Risk of Multiple Pregnancies: By selecting the highest quality single embryo for implantation, the risk of multiple pregnancies is minimized.

• Suitable Conditions: Suitable for cases with more available embryos and a desire to maximize IVF success rates and minimize genetic risks through genetic screening.

The Impact of Timing on IVF Success Rates

The decision of when to perform embryo transfer is based on various factors, including the quality of embryos, the number of available embryos, and the patient's physiological condition. Data suggests that pregnancy rates and live birth rates are typically higher with Day 5 blastocyst transfer compared to Day 3 transfer. Before deciding between Day 3 or Day 5 transfer, thorough consultation with a physician is crucial. Customized recommendations can only be provided by considering specific patient factors such as age, health status, and embryo quality.

Overall, the choice between Day 3 and Day 5 embryo transfer should be a result of comprehensive considerations, not solely based on a simple rule. Each case needs to be thoroughly evaluated based on its unique medical background and reproductive goals. Understanding all feasible options and potential risks is key to maximizing IVF success rates.
 

Behind-the-Scenes Heroes: RSMC's Internationally Accredited Laboratory

For those hoping to increase IVF success rates but lack confidence in cultivating embryos to Day 5, RSMC is the optimal choice. Our laboratory holds top international accreditations, including CPA, the College of American Pathologists (CAP), and the Clinical Laboratory Improvement Amendments (CLIA). While most labs can culture embryos for up to five days, RSMC's lab stands out as one of the few globally capable of extending embryo culture to 7.5 days. Particularly noteworthy is RSMC's leading pass rate in PGT-A testing within the industry. Whether using donor eggs or one's own, our lab consistently achieves pass rates significantly above average, especially in the 42 and older age group, where our PGT-A pass rate reaches 42.86%, surpassing other clinics' 25.9%. This not only demonstrates our technical expertise but also serves as a powerful testament to the professionalism of our team.

RSMC is committed to continually optimizing our techniques to fulfill the dreams of more infertility patients. If you are interested in IVF treatment or need further information on procedures and costs, feel free to contact us to schedule a complimentary virtual consultation with RSMC's Director, Dr. Harari, who brings over 30 years of clinical experience to provide comprehensive fertility advice. Please contact us via Line / WeChat: rsmctw, Whatsapp: +1 858-342-6046.