IVF and Twins
Practically every fertility treatment including In Vitro Fertilization (IVF) increases the risk for multiple births. Depending on the fertility treatment, multiples can represent anywhere from approximately 5 to 35 percent of deliveries. The reason is simple: in 99 percent of natural cycles, only one egg is released from the ovary. The natural multiple prevalence is, therefore, only around one percent, with a large majority of those instances resulting in twins. Since fertility treatments turn a single egg cycle into a multiple egg procedure with ovarian stimulation, the ovaries release more than one eggs, and more than one can be fertilized, resulting in a multiple birth.
Attitudes toward twin births as a result of IVF have been going through a significant change in the past few years. Specifically, more and more colleagues (especially physicians in Europe, but increasingly in the US as well) opt for single-embryo transfer (SET) to eliminate twin or higher-order multiple pregnancies in IVF cycles. In 2010, the government of Quebec, Canada, even enacted a law, requiring SET in all but a handful of special cases. A recent article in the online magazine Slate (which quoted Dr. Gleicher, CHR's Medical Director), the writer explained that this government intervention in Quebec resulted in a reduction in IVF pregnancy rates from 42 percent to 32 percent, a significant drop. At CHR, we feel that this trend poses a threat to the individual patient's right to self-determination, as detailed below.
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Managing IVF and Multiple Birth Risk
Increasingly successful infertility treatments have resulted in an increase in multiple births. Quite rightly, the lay public and medical community have identified this as a major problem. (Remember the Octomom?!) Indeed, Dr. Gleicher was in the vanguard of efforts to reduce multiple births, when he, in a study in the prestigious New England Journal of Medicine in 2000, found the risk for high order multiples (triplets or more) with intrauterine inseminations (IUI) to be uncontrollable and suggested that patients be taken earlier into in vitro fertilization (IVF) (Gleicher et al. N Engl J Med 2000;343:2-7).
Amongst all infertility treatments, IVF gives us the best control over an increased risk for multiples because we (that is, patient and physician) decide how many embryos to transfer into the uterus. The more embryos are transferred, the higher the multiple risk will be though the age of the mother also plays a significant role. As the utilization of IVF in infertility has increased over the last decade, so has our ability to reduce multiple risks.
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Balanced Approach to IVF Pregnancy
CHR Publications on IVF
- Reproductive Biology and Endocrinology Comparing needles with smaller and larger diameters, this study found no difference in oocyte yields between two needle sizes. Smaller diameter needles significantly prolonged time of egg retrieval, suggesting superiority of larger diameter needles in most cases.
Do hormonal contraception prior to in vitro fertilization (IVF) negatively affects oocyte yields? A pilot study.Reproductive Biology and Endocrinology Investigating 43 oocyte donors in 71 IVF cycles, this study found that exposure to high androgenic oral contraceptives prior to IVF cycles suppress functional ovarian reserve and oocyte yields, even in young oocyte donors. The finding of the study suggests that routine use of oral contraceptives in preparation for IVF may require reevaluation, especially in women with diminished ovarian reserve.
- Human Reproduction In response to a Finnish study advocating for single embryo transfer (SET) for even women in their 40s, this article questions the ever-popular trend of SETs in IVF cycles based on risk-benefit analysis of twin and singleton pregnancies following IVF.
CHR has always placed a priority on achieving high clinical pregnancy rates without exposing patients to risk of high order multiples. Many patients bear witness to CHR's conservative embryo transfer policy, even if, at times, it has taken efforts and strong arguments to convince them of the wisdom of such an approach. CHR's embryo transfer policy has always been based on the acceptance of twins and the rejection of triplets or even higher order births. Everybody agrees that singletons represent the lowest risk pregnancy and that, with increasing order of pregnancy, the risk to babies and mothers increases. We've always felt that the additional risk of twinning was minor enough to be more than made up by the benefits a twin pregnancy bestows on an infertile couple - who, quite frequently, want more than one child and for whom having twins is a definite option.
Until recently, most of our colleagues agreed with us. More recently, first starting in Europe but now also in the U.S., an increasing number of colleagues have started to argue that twins are an unfavorable outcome of infertility treatment, something to be avoided at all cost. To this end, many infertility physicians have started advocating for "elective" single embryo transfer (SET). We strongly disagree! Our disagreement with many of our colleagues is based on hard statistical facts, and here is a short summary: The sudden antipathy towards twin delivery stems from the fact that perinatal risk (related to the baby) and maternal risk (related to the mother) in a twin pregnancy are somewhat higher than in a singleton delivery.
But so are the benefits! Most fertility patients want to have more than one child, and for many of them, having twins in just one cycle of IVF is a faster and more economical way to achieve that goal than going through two or more cycles of IVF with one singleton pregnancy each. Yet, this is usually ignored by our colleagues. Risk/benefit calculations form the basis for all decision making in medicine, since nothing in medicine is completely risk-free. Patients and physicians, once risks and possible benefits of a medical intervention are known, make a decision. What level of risk a person is willing to take to achieve a certain benefit, of course, varies between individuals. In other words, patients have an absolute right to take more or less risk, depending on what their desires are and what their risk tolerance is.
For those who want to read more on the topic, CHR physicians have published many articles in peer-reviewed medical journals on this topic of IVF and twins. Here is a short list:
- Gleicher N. Eliminating multiple pregnancies: an appropriate target for government intervention? Reprod Biomed Online 2011; In press.
- Gleicher N, Oktay K, Barad DH. Patients are entitled to maximal IVF pregnancy rates. Reprod Biomed Online 2009;18(5):599-602.
- Gleicher N, Barad DH. Arguments against elective single-embryo transfer. Expert Rev Obstet Gynecol 2008;3(4):481-6.
- Gleicher N, Barad DH. Twin pregnancy, contrary to consensus, is a desirable outcome in infertility. Fertil Steril 2008;91(6):2426-31.
- Gleicher N. Is it time to limit IVF transfers to one embryo? Contemporary Obstet Gynecol 2004;49:73-81.
- Gleicher N et al. Reducing the risk of high-order multiple pregnancy after ovarian stimulation with gonadotropins. New Engl J Med 2000;1:2-7.
If you would like to receive reprints of these articles, please contact us.
IVF Cost-Benefit Analysis
Cost-benefit considerations can, however, be even more complex: Consider the options of a small pregnancy chance with your own eggs against the much larger chance of pregnancy with egg donation. This is practically a daily point of discussion with patients at our center, and, often, more than once daily. "Yes, oocyte donation on a per-cycle basis may be more expensive than a cycle with your own eggs; but consider the difference in pregnancy chance" is something we routinely have to point out. After all, the questions is not whether there is a difference in cost between those two cycle attempts, but whether there is a difference in cost for achieving a pregnancy and giving birth to a child. And these are, of course, very different end points to consider and the cost-benefit consideration will, therefore, be vastly different.
Contact us for a pre-ivf consultation, if you have any questions.
Last Updated: June 28, 2013