The Case for Single Embryo Transfers
SETs, often referred to as elective single embryo transfer (eSET), involve transferring only one embryo into the uterus during an IVF cycle, even when multiple embryos are available. This approach is recommended as the main course of action, because it effectively minimizes the risk of multiple pregnancies, which are notorious for issues such as preterm birth and low birth weight. In contrast, multi-embryo transfers (METs) involve transferring two or more embryos. Though METs increase the likelihood of pregnancy per cycle, they also raise the risk of multiple pregnancies and associated complications. While SET may result in a slight decrease in overall pregnancy rates, it offers a comparable cumulative pregnancy rate when extra embryos are frozen and transferred in subsequent cycles. The primary benefit of SET is the dramatic reduction in multiple pregnancy rates, with twin rates dropping to around 1–2%. In fact, SET pregnancy rates continue to improve as technology and knowledge increase.
Consistent advancements in IVF technology have the potential to improve SET outcomes. For example, better embryo culture techniques allow embryos to reach the blastocyst stage more consistently: Blastocyst-stage embryos, which develop over five to six days, generally have higher chances of implantation than earlier-stage embryos because this longer growth period helps in selecting the most viable embryos and aligning them with the uterus’s readiness for implantation. Additionally, preimplantation genetic testing (PGT) helps in choosing embryos that are more likely to implant successfully and develop healthily. Advances in cryopreservation, especially vitrification, have made it easier to freeze and thaw embryos with high survival rates, which supports strong overall pregnancy rates. Technologies such as imaging and time-lapse monitoring allow for continuous tracking of embryo growth, further aiding in selecting the best embryo for transfer. Lastly, the use of artificial intelligence (AI) in selecting embryos is an exciting development; AI can analyze large amounts of data to more accurately predict which embryos are viable—even consistently outperforming the clinical teams—thus boosting SET success rates. Collectively, these innovations contribute to the growing effectiveness of SET, making it a more viable and often preferred choice in assisted reproductive technology.
Mandating Single Embryo Transfers in the United States
SET in IVF treatments is a critical measure aimed at reducing health risks for both mothers and newborns. The precedent set by Jacobson v. Massachusetts provides a clear and compelling foundation for understanding the state’s authority to regulate public health under its police powers: In this case, the U.S. Supreme Court upheld the state’s authority to enforce mandatory vaccination laws to protect public health. This landmark decision established that individual liberties could be overridden when necessary to prevent significant health threats. Similarly, SET mandates are a modern application of this principle, aimed at mitigating the substantial health risks that mothers and their future children face during and after pregnancy. Just as the state intervened to prevent the spread of smallpox, it can be applied when regulating IVF practices to reduce health risks associated with multiple gestations. Various aspects of reproductive health, some arguably on the same moral plane as SET—such as abortion and surrogacy—are already subject to state regulation. For example, states can now regulate abortion to protect women’s health and safety, with laws requiring informed consent, waiting periods, and specific medical procedures. These regulations are justified on the grounds of public health, ensuring that abortions are performed safely and with minimal risk to the patient.
Judicial precedents provide further support for state intervention in health matters, particularly where the state’s interest in safeguarding maternal health and ensuring public safety is at stake. One of the most relevant cases in this context is Planned Parenthood v. Casey, where the Supreme Court upheld the state’s authority to regulate abortion, so as long as those regulations did not place an undue burden on a woman’s right to choose. In doing so, the Court recognized that “the State has legitimate interests from the outset of pregnancy in protecting the health of the woman and the life of the fetus that may become a child”—a principle that applies with equal force to IVF treatments. Just as the state may regulate abortion to protect maternal health, it has a compelling interest in regulating IVF procedures like SETs to mitigate the risks associated with multiple pregnancies. The risks are well-documented and present serious health challenges that justify the state’s role in implementing policies like SET to ensure safer reproductive practices.
More recently, in Dobbs v. Jackson Women’s Health Organization, the Court reaffirmed the rational basis standard in evaluating state laws related to health and welfare. Under this standard, a law must be upheld if it serves any legitimate state interest, such as the protection of maternal and fetal health. SET mandates easily satisfy this requirement, as they directly promote maternal well-being and the health of newborns by reducing the incidence of high-risk multiple pregnancies. In fact, Dobbs emphasized that states are entitled to significant deference in regulating medical procedures when it comes to protecting health and safety. Therefore, a law mandating SET aligns with the principle that states can enact reasonable health regulations if the rationale behind them is supported by legitimate state interests.
Additionally, the Supreme Court’s ruling in Gonzales v. Carhart provides another important precedent for allowing state regulation of medical procedures to safeguard health. In that case, the Court upheld the federal Partial-Birth Abortion Ban Act, even though it restricted a specific medical procedure, because the law was aimed at protecting both maternal health and fetal life. The court affirmed that when substantial health risks are involved, the state has the authority to regulate medical practices to mitigate those risks. This reasoning is directly applicable to IVF practices, where SET mandates serve to protect maternal health by lowering the risk of complications associated with multiple gestations. Just as the court in Gonzales recognized the state’s power to regulate certain medical practices for health reasons, states have a similar responsibility to address the risks of multiple pregnancies through SET regulations.
As is discussed in greater detail later in this article, when considering the legal feasibility of SET mandates in the United States, it is useful to look at comparative legal frameworks. Helpful in this regard are countries within the European Union and a few U.S. states that have successfully implemented regulations around embryo transfers. Many European countries, including Belgium, Sweden, and the Netherlands, have adopted stringent policies favoring SETs to protect maternal and neonatal health. These countries have seen significant reductions in multiple pregnancy rates and associated health complications, offering a compelling case for similar regulations in the United States. Importantly, these policies balance reproductive autonomy with public health goals, ensuring both patient safety and positive health outcomes.
Closer to home, states like Massachusetts and California offer models of state-level regulation within the U.S., where the states mandate insurance coverage for IVF treatments, encouraging the use of SET to minimize health risks. These frameworks demonstrate that the U.S. is on its way towards practical pathways that regulate reproductive health practices like SET. The regulatory success that multiple states have had in promoting safer reproductive practices illustrates the pragmatism of state intervention in IVF, therefore offering a roadmap for broader adoption of SET mandates across the country.
Arguments Against SETs
While the benefits of SETs in reducing health risks for both mothers and children are well-documented, there remains significant opposition to mandating their use. Critics often cite concerns about lower pregnancy success rates per cycle and the perceived appeal of transferring multiple embryos for reasons of efficiency and emotional security. These concerns, although valid, must be weighed against the considerable medical and financial risks associated with multiple pregnancies.
Mandating SETs Will Lead to Lower Successful Pregnancy Rates
One common counterargument against SETs is that they reduce the overall pregnancy success rate, particularly when compared to transferring multiple embryos. Nevertheless, data has shown that even without transferring multiple embryos, IVF generally yields higher success rates than natural conception, regardless of age. For instance, individuals under the age of 35 have a 54% chance of success per IVF cycle, compared to a 20% chance of natural conception for those under 30. This significant difference underscores the efficacy of IVF as a reproductive option, even when limiting embryo transfers. Although the cited IVF data does not explicitly differentiate between SET and multiple embryo transfers, SET is most commonly employed in younger patients—where success rates are already the highest—indicating that its use does not dramatically reduce the likelihood of pregnancy in these groups.
Moreover, while transferring multiple embryos may slightly increase the chance of pregnancy per cycle, the associated health risks to both the mother and children, such as preeclampsia, gestational diabetes, and premature birth, provide a strong justification for prioritizing SET. The marginal reduction in success rates from SET should be viewed in light of these substantial maternal and fetal health benefits. Additionally, the use of PGT can further bolster the success rates of SET by identifying and transferring the healthiest embryo, thereby mitigating some of the risks associated with lower success rates in single transfers. Another key consideration when addressing concerns about SET and pregnancy success rates is the role of donor eggs in IVF cycles. When the prospective mother is using a donated egg from a younger donor, the success rate is based on the donor’s age rather than the recipient’s. This means that, even if the mother is older, the chances of a successful pregnancy align with the higher success rates typically seen in younger women. This underscores the value of SET in such cases, as it allows for the reduction of health risks associated with multiple births, without necessarily compromising the overall likelihood of success. Therefore, for older patients using donor eggs, SET can still offer a strong chance of pregnancy success while prioritizing maternal and fetal health. Overall, while concerns about lower success rates with SET are valid, the overall benefits of reduced health risks and the use of alternate techniques, like genetic testing or egg donation, ultimately support its implementation in IVF protocols.
The Appeal of Multiple Embryos at Once
Many couples undergoing IVF treatments express a desire for multiple embryos, with the hope of conceiving twins, for a variety of reasons, such as: they want to avoid another IVF attempt, they want to avoid waiting lists, or because they do not see the risks as severe. For those struggling with infertility, the idea of “safety in numbers” can provide a sense of security. The ability to freeze additional embryos offers peace of mind to couples who may want more than one child or who worry about the cost and emotional toll of undergoing multiple IVF cycles. For older women, this also presents the opportunity to use their eggs before they age further. Extra embryos act as a safeguard in case the initial cycle does not result in a successful pregnancy or ends in miscarriage.
Though these are understandable desires, it is important to acknowledge the significant risks associated with multiple gestation pregnancies, especially when conceived through IVF. In fact, twin pregnancies are six times more likely to result in preterm delivery, which can lead to complications such as learning disabilities and cerebral palsy. While these risks are not guaranteed—six out of 10 twins will be born before 37 weeks—these elevated risks make the state’s interest in protecting maternal and child health even more pressing. There are additional health risks associated with IVF twin pregnancies. Short-term problems include lung, heart, brain, blood, digestive, and immune complications, while long-term complications may include cerebral palsy, learning deficiencies, and other vision/hearing/dental/mental hurdles.
The health risks to both mother and child are not the only concerns associated with multiple pregnancies. Research has shown that parents of IVF twins tend to face more mental health challenges and report poorer parent-child interactions during the early years when compared to parents of singletons. These difficulties may lessen over time, as studies on IVF twins in middle childhood have found no significant long-term developmental issues and, in some cases, even optimal adjustment when compared to singletons. However, this does not negate the significant mental and physical strain experienced by parents during the earlier stages of parenting twins.
Additionally, the financial and medical challenges associated with twin pregnancies should not be overlooked. Twins are five times more likely to be admitted to the ICU compared to single babies, which leads to increased healthcare costs. Other complications include a higher chance of birth defects, premature labor, cesarean sections, and extended recovery times, all of which can place an additional financial burden on families. Prolonged bed rest or time off work may also be necessary, further compounding the financial strain.
Given these risks, the state’s interest in promoting maternal and child health through policies favoring SET over multiple embryo transfers becomes clear. While the emotional and financial appeals of twins are significant, the associated risks—physical, emotional, and even financial—justify creating mandated SETs regulating the use of embryo transfers to protect the well-being of all parties involved.
Potential Policy Solutions
Although widespread recognition exists regarding the health risks associated with multiple embryo transfers, the lack of enforceable SET regulations across the United States leaves a critical gap in reproductive health policy. A handful of states have implemented progressive policies to encourage safer practices, but these efforts remain uneven and insufficient to address the broader risks. To bridge this gap, a cohesive framework is needed—one that draws on successful state and international models while balancing patient autonomy with public health goals.
Examining Current State Policies on Embryo Transfers
Despite the American Society for Reproductive Medicine’s (ASRM) recommendation advocating for SETs as a way to reduce the health risks associated with multiple pregnancies, there are no enforceable regulations across the United States mandating this practice. The ASRM guidelines suggest that SET should be the standard practice in certain cases, especially for women aged 38 years or younger or those with a favorable prognosis. However, these guidelines are not binding, and adherence remains voluntary, leading to wide variation in how IVF clinics and states implement SET recommendations.
In states like Massachusetts and California, progressive policies have been implemented to promote safer reproductive practices. Massachusetts mandates insurance coverage for IVF treatments, which often includes provisions that encourage the use of SET. By reducing the financial burden on patients, the policy promotes safer outcomes by discouraging multiple embryo transfers, which carry significant risks for both mothers and babies. Similarly, California’s recent SB 729 law, which takes effect on July 1, 2025, expands insurance coverage to explicitly include up to three egg retrievals and unlimited embryo transfers, while specifically mentioning the use of SET. Both states demonstrate how comprehensive insurance mandates can reduce financial pressures that may otherwise push patients toward multiple embryo transfers, which carry significant risks for mothers and babies.
On the other hand, there are states that either lack policies or are becoming problematic for IVF in general. For example, Texas has more lenient regulations, offering no specific limits on the number of embryos that can be transferred during IVF. This regulatory gap contributes to higher rates of multiple pregnancies and their accompanying increased risks of complications such. While Alabama has no strict policies on IVF embryo transfers, the state may be on its way to implementing significant constraints due to its evolving legal landscape. The Alabama Supreme Court has recently granted legal personhood to frozen embryos, which has introduced significant complexities for reproductive choices and access to fertility treatments. This controversial decision allows claims of wrongful death to be brought for the destruction or mishandling of embryos, essentially shifting how embryos are treated under Alabama law.
Alabama’s ruling has already had tangible effects: some IVF clinics in the state, including the University of Alabama at Birmingham, have paused operations while assessing the legal risks and compliance requirements. The decision raises profound questions for IVF practices, as it potentially subjects routine procedures—such as discarding unused embryos or even equipment malfunctions—to heightened liability. This could lead to prohibitive costs for patients due to increased cycles and storage fees, complicating access to IVF not only in Alabama but in any state influenced by this precedent.
By framing embryos as “persons,” Alabama’s decision highlights the absence of uniform regulations on embryo transfers in the United States and the potential for such rulings to drive inconsistent policies that jeopardize patient safety and treatment accessibility. While states like Massachusetts and California focus on expanding access and promoting safer practices through insurance mandates, Alabama’s approach and Texas’ lack of foresight underscores the risks of allowing disjointed and conflicting legal interpretations. Discrepancies such as these illustrate the need for cohesive policies—like a SET mandate—to ensure reproductive health practices are effective, equitable, and available.
Drawing on Best Practices for Model Policies
To create more cohesive and effective regulations surrounding embryo transfers, particularly SETs, policymakers should look to adopt the best practices from states and countries that have seen success in promoting SET as a safer and more cost-effective option for IVF. A model policy could incorporate several elements drawn from current approaches while addressing gaps in enforcement and patient safety. First, states could benefit from following models set by Massachusetts and California, both of which mandate insurance coverage for IVF treatments, including provisions for SETs. Massachusetts’ policy promotes safer practices by reducing financial barriers to SET, and California’s SB 729 builds on this foundation by explicitly expanding access to IVF coverage for multiple retrievals and transfers. By alleviating financial pressures, these policies incentivize patients to follow medical guidelines that recommend SET, minimizing the health risks associated with multiple pregnancies. This approach could be expanded nationally, with the aim of reducing the prevalence of multiple pregnancies, which present higher risks of complications. Similarly, European countries such as Belgium, the Netherlands, Sweden, and Slovenia have effectively used public funding to support SET by ensuring that insurance companies only cover SET in eligible cases. By doing so, these nations have significantly lowered the rate of multiple births while maintaining high pregnancy success rates. U.S. states could adopt a similar approach, with government-subsidized IVF treatments focusing on SET as the primary standard for patients with favorable prognoses.
To enforce SET policies, states could implement consequences for medical facilities and practitioners rather than patients. One potential framework could involve professional medical sanctions; clinics and doctors who consistently ignore SET guidelines without appropriate medical justification could face penalties from state health authorities or regulatory bodies. Such penalties could range from fines to the suspension or revocation of medical licenses in extreme cases. This type of enforcement would encourage adherence to SET guidelines while maintaining patient autonomy. Another consequence for non-compliance could be the loss of public funding or insurance coverage. In countries like Belgium and the Netherlands, failure to adhere to SET protocols can lead to the withdrawal of financial support for IVF treatments. In the U.S., insurance companies could be encouraged or required to cover only SET procedures, in accordance with ASRM guidelines. Clinics that fail to comply would risk losing essential funding, providing a significant incentive to follow best practices.
To further promote these safer reproductive practices, expanding public funding for IVF treatments, especially those prioritizing SET, would bring U.S. policies closer in line with global standards. While the ASRM provides clear guidelines advocating for SET in many cases, making these recommendations mandatory under certain conditions could significantly improve maternal and fetal health outcomes. For example, states could model their laws after Sweden, where SET is the most common method to minimize the risk of twin pregnancies, with the occasional option to transfer more embryos based on individual risk assessments and patient consent.
Incorporating these practices into a national framework would help standardize reproductive health practices across the country, reducing the risks associated with multiple pregnancies while ensuring that patients have access to safe and effective fertility treatments.
SET as the Default with Controlled Flexibility for Double Embryo Transfers
While SET has benefits in minimizing the risk of multiple pregnancies, there are certain circumstances where double embryo transfers (DETs) could be considered. Policymakers can reinforce SET as the recommended approach, while allowing DET in select cases based on patient-specific factors, following the guidance from the European Society of Human Reproduction and Embryology (ESHRE). The ESHRE recommendations provide a nuanced approach to determining when DET may be appropriate; for instance, previous unsuccessful ART treatments should not automatically lead to a decision to perform DET instead of SET. Research suggests that there is no significant improvement in clinical pregnancy rates when two embryos are transferred compared to one, and increasing the number of embryos per transfer does not compensate for prior failed cycles.
Similarly, the duration of infertility should not be considered a decisive factor when determining whether DET is appropriate. Evidence indicates that this factor does not significantly impact live birth rates when comparing SET and DET cycles, reinforcing the safety benefits of SET.
However, female age presents a more complex case. While it has been suggested that older women (typically over 38 years old) may benefit from DET, the evidence does not clearly support this assumption. Although some studies suggest a higher live birth rate following the first transfer cycle in older women who undergo DET, cumulative live birth rates do not show a significant difference. Moreover, advanced maternal age carries its own health risks, such as preterm birth and hypertensive disorders, which are exacerbated in the case of multiple pregnancies. For this reason, the risks associated with multiple pregnancies in older women should be carefully weighed against the potential benefits of DET.
The ESHRE guidelines underscore the importance of patient-specific factors in ART treatment decisions. A balanced approach, where SET is prioritized but DET is permitted based on age, health, and previous ART history, has potential to improve maternal outcomes while maintaining flexibility for patients. Clear communication between medical professionals and patients during the planning phase is essential to ensure that all risks are considered when determining the number of embryos to transfer.
Legislative and Regulatory Implementation
To effectively reduce the health risks associated with multiple embryo transfers in IVF treatments, states should consider adopting a regulatory framework that mandates SET in specific circumstances. Drawing on the successful models from the EU and Massachusetts, this section proposes a model law that balances reproductive autonomy with the state’s compelling interest in protecting maternal and neonatal health. The Model Law is as follows:
Model Law: Single Embryo Transfer Mandate
The following is a proposed legislative framework that U.S. states could adopt to regulate IVF practices, ensuring safer reproductive outcomes while respecting patient choice.
General Rule: Mandatory SET
All ART clinics within the state shall be required to perform SETs as the default practice for patients under the age of 38 or with a favorable reproductive prognosis, unless specific conditions warrant a double embryo transfer.
Limited Exceptions for Double Embryo Transfers
DET may be permitted in cases where:
- The patient is 38 years of age or older;
- The patient has experienced two or more failed IVF cycles;
- The patient has strongly supported the use of DET;
- The patient has medical documentation justifying a higher likelihood of success through DET; and
- The patient’s physician, through a reasonable degree of medical certainty, has suggested that the patient is a good fit for DET and is unlikely to suffer from the additional embryo.
In all such cases, the decision to transfer two embryos must be justified by the ART clinic and reported to state health authorities.
Reporting and Oversight
ART clinics must report the number of embryos transferred per cycle to the state health department. The department shall monitor compliance and ensure that exceptions to SET are properly documented. Clinics that violate the SET mandate without proper justification may face penalties, including, but not limited to, fines or revocation of their license to operate.
Financial Support and Insurance Coverage
States should work in conjunction with insurance providers to ensure that SET procedures are fully covered under state-mandated insurance plans. In cases where additional cycles are required due to the use of SET, insurance shall cover those cycles without additional financial burden to the patient.
Public Education Campaign
The state shall initiate a public health education campaign aimed at informing patients about the benefits of SET, the risks associated with multiple pregnancies, and the reasons behind the mandatory SET policy. This campaign should also provide resources for patients seeking guidance on their reproductive options.
Enforcement and Penalties
States must implement effective enforcement mechanisms to ensure compliance with SET mandates. Penalties for non-compliance should include fines and suspension or revocation of medical licenses for clinics that repeatedly fail to adhere to the mandate.
State health departments should oversee ART clinics, conducting audits and ensuring that all exceptions to the SET policy are properly justified. Clinics found to be non-compliant may also face removal from state health insurance networks, which would restrict their ability to serve insured patients.
Conclusion
In the aftermath of the Dobbs decision, states face both the challenge and opportunity to shape reproductive healthcare policy. The decision reinforced broad state authority to regulate healthcare under a rational basis standard, making it imperative for states to address pressing gaps in IVF regulation. Without cohesive policies, patients and providers remain vulnerable to health risks and legal uncertainties, as highlighted by Alabama’s personhood ruling in LePage.
At the same time, examples from Massachusetts, California, and the European Union demonstrate that thoughtful, evidence-based regulations can promote maternal and neonatal health while maintaining equitable access to care. A national framework mandating SETs, as proposed here, balances public health priorities with patient autonomy through clear statutes, insurance support, and public education.
Dobbs has shifted the responsibility for healthcare regulation to the states. Policymakers now have the chance to lead with evidence-driven reforms like SET mandates, fostering safer and more responsible IVF practices. The time to act is now, ensuring that reproductive technologies serve the best interests of current and future generations.
Lastly, it is not enough for states to rely on the ASRM’s recommendations, as many currently do. In this post-Dobbs era, states have a responsibility to establish a legal standard that reflects a true commitment to maternal and neonatal health. The evidence, both legal and medical, leads toward this necessary reform.
