Every Intended Parent asks how many embryos they should transfer during their surrogacy program. Many doctors will disagree on this issue, but in general the higher the success rate of your clinic, the fewer embryos are likely to be transferred.

Twin pregnancies and embyro transfersIn the United States, the ASRM urges clinics to transfer only one embryo per transfer procedure (in an attempt to limit the number of twins pregnancies).

The typical protocol in overseas clinics is to transfer two viable embryos if they are fresh and healthy.

In clinics in Kenya or other developing countries, three embryos is the maximum, and is usually only transferred if the embryos are of quite poor quality.

Each embryo has a significant chance of producing a pregnancy – so each additional embryo also increases the likelihood of multiple births – twins or triplets. Multiple births often lead to complications in the pregnancy, which risks the health of the fetus and the surrogate mother and can add significant financial costs for NICU care for premature babies.

The common belief is that surrogacy works best if you transfer more embryos — resulting in more pregnancies. But multiple embryos produce multiple births and serious risks. Moreover, clinic data shows that transferring more than one embryo doesn’t significantly improve the live birth rate, only the number of twins.

Twins pregnancies have much higher risks for premature birth and other complications. Over 60% of twins are born premature (born before 37 weeks). Twins often don’t have a chance to reach a healthy weight before they’re born, weighing on average about 2 pounds less then singleton babies. Other conditions are more common in multiple pregnancies, including preeclampsia, Gestational diabetes and placental abruption.

There are also expenses related to a twins pregnancy… Intended Parents should plan for both direct and indirect costs to having a twins.

Direct expenses… If the surrogate comes pregnant with twins she will be entitled to additional compensation. She is also entitled to additional expense for bed-rest if the doctor prescribes (and with a twins pregnancy the doctor is very likely to prescribe bed rest). It may also take somewhat longer to find a surrogate candidate who will accept a purposeful twins pregnancy.

Indirect expenses… Twins pregnancies very often end prematurely, meaning that the babies will likely need to spend time in NICU in hospital. Aside from long-term developmental concerns with a premature birth, the NICU costs can add significantly to the overall medical expenses. Overseas hospitals will charge from $500 to $1000 USD per day for NICU care, and a stay of several weeks is not uncommon. In the United States insurance will cover most of the NICU care, but parents should assume to pay $5,000 USD per baby as an out-of-pocket deductible (plus another $5,000 USD if the surrogate also needs medical care).

Although the ASRM recommends against purposely attempting a multiple birth pregnancy because of the health risks to the surrogate and the babies, many clinics will transfer multiple embryos if the parents insist. But the general recommendation is to transfer just one embryo with an objective a singleton delivery.

Of course for desperate couples spending their life savings on a one-time shot at a pregnancy, these risks seem quite hypothetical compared to the lower birth rate. Most believe the likelihood of a pregnancy is higher if you transfer multiple embryos — although some researchers argue that in many cases multiple embryos may decrease the chance of pregnancy.

Forbes has compiled data that tracks the success of IVF procedures, including how often FET procedures transferred one or two embryos, and how often they resulted in twin pregnancies. The data reports procedures for mothers mothers under 35 years old. (Not surprisingly, women under 35 have a higher chance of giving birth to twins.)

A review of the data shows that the clinics with the highest overall birth rates are also those that most often perform transfers with multiple embryos. However in general there is little correlation between the use of multiple embryos and birth rate. Most IVF clinics do not show a higher total birth rate when they transfer multiple embryos — only a higher twins birth rate.

The results suggest that multiple embryo transferred do indeed improve the likelihood of pregnancy, and significantly increase the likelihood of twins pregnancies. Whether that’s a good thing or a bad thing depends on your point of view. Here are a few samples from the data…

  • Top of the list, the Reproductive Associates of Delaware transferred single embryos in almost all cases (95% of the time) and had a birth rate of 37.1%. (Needless to say they had virtually no twins births.)

  • Compare that to the Bluegrass Fertility Center in Kentucky, which transferred multiple embryos in about 98% of cases, and had a live birth rate of 29.6% of cases (and twins birth rate of 11%).

  • The highest twins birth rate was from the Fertility Center of Dallas, with 29% of procedures resulting in a twin birth. Likewise they report transferring single embryos in abut 93% of cases, and had a singleton birth rate of 30%.

  • Our partner HRC Clinic in Los Angeles transfers multiple embryos about 50% of the time and has a 50% singleton pregnancy rate and a 13.5% twins pregnancy rate.

While clinics should continue to move towards single embryo transfers, in some cases the implantation of a second embryo may still be advisable. Clinics should be upfront with patients about the success rate of single embryo implantation, and prepared to take a path that will ultimately have the patient’s best interest in mind.


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