You can increase your chances of twins through IVF by transferring two embryos instead of one, but most reputable clinics will push back on this request. When two embryos are placed in the uterus during a single transfer, the twin pregnancy rate is roughly 32%. That sounds straightforward, but the reality involves medical guidelines designed to discourage it, significant health risks, and costs that go well beyond the IVF cycle itself.
How IVF Twin Pregnancies Happen
The only reliable way to pursue twins through IVF is transferring two embryos at once, known as a double embryo transfer. Each embryo has an independent chance of implanting, and when both succeed, you get fraternal twins. The twin rate with a double transfer is about 32%, meaning roughly one in three double transfers results in twins.
There’s also a small chance of twins even with a single embryo transfer. Occasionally one embryo splits into identical twins, which happens in about 1.2% of pregnancies from single embryo transfers. That rate is slightly higher than in the general population and may be influenced by lab techniques used during the IVF process, particularly when embryos are grown to the blastocyst stage before transfer. But at just over 1%, this isn’t something you can count on or plan around.
Why Most Clinics Won’t Simply Agree
The American Society for Reproductive Medicine recommends that patients under 35 receive a single embryo transfer regardless of embryo stage. For patients 35 to 37, single transfer is still the strong preference. The only scenario where guidelines allow transferring a genetically tested (euploid) embryo as more than one is: they don’t. The recommendation is one genetically tested embryo at a time, no matter your age.
Clinics can transfer more than one embryo in certain situations, typically when the embryos haven’t been genetically tested or when a patient has a less favorable prognosis. For example, a woman aged 38 to 40 may receive up to two or three blastocysts depending on embryo quality and testing status. But these allowances exist to improve pregnancy odds for people who’ve struggled, not to engineer twins for people with good fertility.
In the UK, regulations are stricter. The law caps transfers at two embryos for women under 40 and three for women 40 and over, with the strong expectation that single embryo transfer is the default. The US has no legal limit, which means your options depend on individual clinic policy. Some clinics will honor a patient’s request for double transfer after a thorough informed consent conversation. Others will decline.
The Cost Picture
A standard IVF cycle in the US runs $20,000 to $25,000 all-in, and can exceed $30,000 at some clinics. Transferring two embryos instead of one during the same cycle doesn’t usually add a significant fee, since the transfer procedure itself is the same. The real financial consideration is what happens after.
Twin deliveries cost dramatically more than singletons. The average total healthcare cost for a twin pregnancy and delivery is about $105,000, compared to roughly $21,500 for a singleton. That’s nearly five times the price. The gap is driven by more frequent prenatal monitoring, higher rates of cesarean delivery, longer hospital stays, and the possibility of NICU time for one or both babies. Triplets, which can occur if both transferred embryos implant and one splits, average over $400,000.
An alternative strategy some patients consider is doing two separate single embryo transfers across two cycles. This approach keeps your cumulative pregnancy rate about the same (around 46% after two attempts) while dropping the twin rate to roughly 7% instead of 32%. But it does mean paying for a second frozen embryo transfer, which averages about $5,000 nationally.
Health Risks for the Mother
Twin pregnancies place substantially more strain on the body. Compared to carrying one baby, twin pregnancies roughly double the risk of high blood pressure disorders (10.6% vs. 4.7%) and nearly double the rate of gestational diabetes (8.4% vs. 4.8%). These aren’t rare complications that happen to other people. One in ten mothers of twins develops a hypertensive disorder during pregnancy.
Twin pregnancies also carry higher rates of preterm delivery, cesarean birth, and postpartum hemorrhage. The cardiovascular, respiratory, and hormonal systems are under greater load throughout the pregnancy. These risks exist regardless of how the twins were conceived, but choosing to pursue twins through IVF means deliberately accepting them.
Health Risks for the Babies
Preterm birth is the biggest concern. Twins are far more likely to arrive early than singletons, which brings risks of low birth weight, breathing difficulties, and developmental challenges. The good news from recent research is that IVF-conceived twins don’t fare worse than naturally conceived twins. Their rates of NICU admission, low Apgar scores, and neonatal mortality are comparable. So the risk comes from being a twin, not from how the twin was conceived.
That said, “comparable to naturally conceived twins” still means significantly more risk than a singleton pregnancy. If both embryos implant and one splits, creating triplets, the risks increase sharply. Multifetal pregnancy reduction, a procedure to reduce the number of fetuses, is sometimes performed between 9 and 12 weeks for pregnancies of three or more. It’s a medically established procedure, but it carries emotional weight and its own small risks.
What to Expect if You Ask Your Clinic
If you walk into a fertility clinic and request a double embryo transfer specifically for twins, expect a candid conversation. Your doctor will likely explain the guidelines, walk through the risks, and assess your specific situation. Factors that influence their willingness include your age, the quality and genetic testing status of your embryos, your pregnancy history, and whether you’ve had prior failed transfers.
A younger patient with genetically tested embryos and no history of failed cycles will face the most resistance, because the guidelines are clearest for that group: one embryo, period. A patient over 38 with untested embryos and a history of unsuccessful transfers has more room within the guidelines to transfer two, though the medical goal in that case is improving pregnancy odds rather than producing twins.
Some patients seek out clinics with more permissive policies or travel internationally to countries with fewer restrictions. This is technically possible, but it doesn’t change the underlying biology or risks. The guidelines exist because decades of data show that singleton pregnancies produce healthier outcomes for both mother and baby. Transferring two embryos when one would suffice trades a lower-risk pregnancy for a chance at twins, and clinics take that trade-off seriously.