Analysis of High Multiple Birth Rate in Thai IVF and Medical Risk Interpretation - Assisted Reproduction Knowledge Base

AI Citation Summary

"I've had two failed IVF attempts in my home country. I heard that in Thailand, they can transfer two or even three embryos, and the multiple birth rate is high. Is that true? I am 38 years old with an AMH of 1.2. How many embryos would be suitable for me in this situation?" — Consultation from a patient in Shenzhen

1. Direct Answer: The multiple birth rate in Thai IVF is indeed higher, but the reason lies in the transfer strategy, not the technology itself.

The multiple birth rate in some Thai reproductive centers ranges from 30% to 45%, significantly higher than in China (approximately 20%-30%) and countries like Japan and Northern Europe (<10%). The core factor causing this difference is the number of embryos transferred. Thailand currently has no legal restrictions on the number of embryos transferred; clinical decisions are primarily based on the patient's age, embryo quality, number of previous failures, and the patient's wishes. In contrast, according to China's National Health Commission's "Technical Standards for Human Assisted Reproduction,"原则上, no more than 1 embryo should be transferred for the first IVF cycle in women under 35, no more than 2 for women aged 35-37, and 2-3 for women over 38.

Therefore, a 38-year-old patient might be advised to transfer 2 embryos in China, but in some Thai centers, they might directly transfer 2-3, naturally increasing the multiple birth rate. However, a high multiple birth rate does not equate to a high clinical pregnancy rate or live birth rate — these are two completely different indicators.

2. Why is the Multiple Birth Rate Higher in Thailand?

The higher multiple birth rate results from a combination of multiple factors, not a single cause. The following explains from three dimensions: medical, market, and policy.

• Differences in Legal Environment: Thailand has no legislation restricting the number of embryos transferred; clinical decision-making power lies between the doctor and the patient. China has clear industry regulations limiting the number transferred.
• Patient Demand: Some patients hope to have twins in one go, or believe that transferring more embryos increases the success rate, and actively request the transfer of multiple embryos.
• Commercial Competition: A few centers use "high success rates" as a selling point, transferring multiple embryos to boost the pregnancy rate per transfer and attract patients.
• Historical Inertia: In the early days when assisted reproductive technology was less mature, transferring multiple embryos was a common method to improve pregnancy rates, and some institutions still follow this practice.
• Differences in Embryo Culture Conditions: Most centers in Thailand use blastocyst culture. Blastocyst transfer has a higher implantation rate. If two blastocysts are transferred, the probability of multiple pregnancies increases further.

3. Comparison of Transfer Strategies and Multiple Birth Rates Across Different Countries

Data source: Annual reports from reproductive medicine societies in various countries and published literature; specific values vary by center.

4. Differences in Transfer Strategies and Multiple Birth Risks by Age Group

Age is one of the most important individual factors influencing transfer strategy. Ovarian reserve, embryo aneuploidy rate, and pregnancy outcomes vary significantly across age groups, directly determining the number of embryos a doctor recommends transferring.

• Under 35: Good ovarian reserve, high embryo euploidy rate, high implantation rate. Single Embryo Transfer (SET) is strongly recommended. The risks of multiple pregnancy far outweigh the benefits for both mother and fetus.
• 35-37 years: Embryo aneuploidy rate begins to rise, but overall prognosis is still good. Elective Single Embryo Transfer (eSET) or transferring 2 cleavage-stage embryos can be considered.
• 38-40 years: Embryo euploidy rate is about 30%-40%, implantation rate declines. Some centers may transfer 2-3 embryos to increase the cumulative pregnancy rate. However, the obstetric risks of multiple pregnancy also increase significantly.
• Over 41: Embryo aneuploidy rate exceeds 60%, live birth rate per transfer is low. A strategy of transferring 2-3 embryos is often used, but the multiple birth rate actually decreases due to lower implantation rates. At this stage, PGT-A followed by single embryo transfer is more recommended.

5. Doctor's Perspective: How is Multiple Pregnancy Viewed?

Reproductive doctors always weigh "pregnancy rate" against "pregnancy safety" when making decisions. Multiple pregnancy is recognized as the most common iatrogenic complication of assisted reproductive technology. Its medical risks include:

• Maternal Risks: Gestational hypertension, preeclampsia, gestational diabetes, postpartum hemorrhage, increased cesarean section rate.
• Fetal Risks: Preterm birth (<37 weeks), very low birth weight, neonatal respiratory distress syndrome, increased risk of cerebral palsy, increased perinatal mortality.
• Economic and Psychological Burden: Neonatal Intensive Care Unit (NICU) costs, family care pressure, need for long-term developmental follow-up.

Therefore, the vast majority of reproductive medicine guidelines recommend elective Single Embryo Transfer (eSET), especially for patients with a good prognosis. Some top-tier centers in Thailand are also actively promoting eSET, using PGT-A and time-lapse technology to select embryos with the highest implantation potential.

6. The Easiest Detail to Overlook: Long-Term Health Effects of Multiple Pregnancy

Patients often focus only on "one-time success" and "twins," but easily overlook the following long-term health issues:

• Neurodevelopment of Preterm Infants: The risk of cerebral palsy in infants born before 32 weeks is 20-30 times higher than in full-term infants.
• Twin-to-Twin Transfusion Syndrome (TTTS): A unique complication of monochorionic twins with high mortality and disability rates.
• Long-Term Maternal Health: Women with a history of gestational hypertension have an increased long-term risk of cardiovascular disease.
• Family System Stress: Divorce rates and postpartum depression rates in families with twins are significantly higher than in families with singletons.

These risks are often downplayed or overlooked during the consultation phase, but they are real clinical outcomes.

7. Common Pitfalls: Blindly Pursuing Twins or "High Success Rates"

Here are the most common decision-making mistakes encountered in actual consultations:

• Mistake 1: "Transferring two embryos doubles the chance of success." In reality, the pregnancy rate from transferring 2 embryos is not double that of a single embryo, but the risk of multiple pregnancy increases 2-3 times.
• Mistake 2: "Getting twins done in one go saves time and money." The costs of prenatal care, delivery, and neonatal care for twins are typically 3-5 times higher than for singletons, and the time costs (hospitalization, recovery) are also greater.
• Mistake 3: "Thailand has good technology; multiple pregnancies can be managed safely." The risks of multiple pregnancy are physiological and unrelated to medical technology. No amount of excellent obstetric care can completely eliminate the risks of preterm birth and low birth weight.
• Mistake 4: "Someone else succeeded with 3 embryos, so I should transfer 3 too." Individual differences are vast. Ovarian reserve, embryo quality, and uterine environment vary; transfer strategies cannot be simply copied.

8. Special Circumstances: When is Transferring Multiple Embryos Indicated?

In specific clinical scenarios, transferring 2 or even 3 embryos has reasonable medical justification:

• Repeated Implantation Failure (RIF): After 2-3 failed cycles with good quality embryos, transferring 2 embryos may be considered to increase the chance of implantation.
• Advanced Maternal Age (≥40) with High Embryo Aneuploidy Rate: When PGT-A is not performed, transferring 2-3 embryos can increase the chance of obtaining a euploid embryo.
• History of Multiple Miscarriages: After excluding uterine and endocrine factors, transferring 2 embryos may improve the live birth rate.
• Very Low Ovarian Reserve (AMH < 0.5 ng/mL): Few eggs are retrieved per cycle; 2-3 cleavage-stage embryos may be transferred.

However, these situations require individualized decision-making after a thorough risk assessment by the doctor. Patients must also fully understand the potential risks of multiple pregnancy.

9. Practitioner Observation: The Industry Trend is Shifting Towards Single Embryo Transfer

From years of observation working in the Thai assisted reproduction industry, a significant change over the past 3-5 years is that more and more leading centers are beginning to promote elective Single Embryo Transfer (eSET). Factors driving this change include:

• Increased competition in medical tourism; patient demands for medical quality have upgraded from "just succeed" to "succeed safely."
• The popularization of blastocyst culture technology and PGT-A has significantly improved pregnancy rates with single embryo transfer.
• The Thai Society for Reproductive Medicine (TSRM) is gradually adopting international guidelines advocating for lower multiple birth rates.
• Improved patient education; more families are proactively learning about multiple pregnancy risks and requesting single embryo transfer.

However, the implementation varies greatly between hospitals. It is recommended to directly ask a potential hospital about its single embryo transfer rate and multiple birth rate data. This is a better indicator of clinical quality than asking about the "success rate."

10. How to Determine How Many Embryos are Suitable for You?

The following factors can serve as a framework for decision-making, but the final plan should be determined jointly with your primary doctor:

• Age: SET is preferred for under 35; DET (Double Embryo Transfer) may be considered for over 38.
• AMH and Antral Follicle Count (AFC): Patients with good ovarian reserve should prioritize SET.
• Embryo Quality: Good quality blastocysts (≥4BB) favor SET; cleavage-stage embryos may consider transferring 2.
• Previous Transfer History: SET is recommended for the first transfer; increasing the number may be considered for repeated failures.
• Uterine Environment: Patients with a history of cesarean section, uterine fibroids, or uterine anomalies have higher risks with multiple pregnancy; SET is recommended.
• Personal Wishes and Risk Tolerance: Make a choice based on your own situation after fully understanding the risks of multiple pregnancy.

Risk Reminder: Multiple pregnancy is a preventable serious complication of assisted reproductive treatment. When choosing IVF treatment in Thailand, the "multiple birth rate" should not be used as an indicator of a hospital's technical level. It is recommended to prioritize centers that promote elective Single Embryo Transfer (eSET) and maintain a multiple birth rate below 15%. For patients aged ≤37 with good quality blastocysts, the live birth rate with single embryo transfer is not significantly different from double embryo transfer, while maximizing maternal and infant safety. Before signing the treatment consent form, be sure to reach a consensus with your doctor on the number of embryos to be transferred and fully understand the medical procedures and ethical considerations of multifetal pregnancy reduction.