PRAGUE — If given the choice between a singleton or twins, many patients undergoing in-vitro fertilization would prefer twins, according to several studies presented at the annual meeting of the European Society for Human Reproduction and Embryology.
At a time when many fertility clinics are actively trying to reduce their multiple birth rates by limiting the number of embryos they transfer after in-vitro fertilization (IVF), this patient attitude goes against most physicians' concepts of treatment success, said Dr. Graham Scotland, an investigator on one of the studies.
It has been assumed that much of the patient drive for transferring more than one IVF embryo has been linked to increasing their chances of becoming pregnant with a singleton.
But a Danish study has found that while this is true for some couples, almost 60% simply want twins. Dr. Hans Jakob Ingerslev surveyed 588 couples using a 56-item questionnaire and found that 96% wanted two or more children in their family. Roughly 58% of the couples preferred twins, 38% preferred one child at a time, and the rest had no preference, said Dr. Ingerslev of the fertility clinic at Skejby Sygehus, a large university hospital in Aarhus (Denmark).
There were 60 couples in which the female partner wanted twins but the male wanted singletons—giving female gender an odds ratio of 1.65 for wanting twins.
Asked if they would accept a single embryo transfer (SET) if they were given an unlimited number of free cycles, 73% of couples said no. Moreover, offered free IVF treatment to conceive a second child later, 68% said no, Dr. Ingerslev said.
Among subjects who did not want twins, 24% cited risks to the fetus as their reason, while 18% cited maternal risks and 11% cited obstetric complications. Among those wanting twins, 23% cited wanting their child to have a sibling and 22% said they had a positive attitude about twins.
“Counseling these patients is a challenge,” he said.
Another study uncovered the depth of some patients' reluctance to accept SET, although it is unclear whether their motivation was for twins specifically or simply to increase their chances of pregnancy. In a survey of 81 couples waiting for IVF treatment, Dr. Scotland asked patients to weigh the possibility of treatment failure against the types of complications they could face if they were to conceive twins.
In general, patients preferred the idea of having twin-related complications such as a child with physical or cognitive impairment over the prospect of treatment failure and childlessness, said Dr. Scotland, from the University of Aberdeen in Scotland. However, they ranked perinatal death as less desirable than treatment failure.
“This is an interesting and surprising finding. Perhaps we should listen more carefully to the values of our patients who want double-embryo transfer,” said Dr. Scotland, noting that the absolute risks of conceiving twins are low, and the chances of twin-related complications are even lower.
“For some of these outcomes you're looking at something like 1% of twin pregnancies that will experience these adverse outcomes. Particularly difficult is that when you listen to a patient's values you have to weigh that against the fact that the risk is to another person—to the future offspring,” he said in an interview.
Indeed it is important to remember that most twin pregnancies have no complications, added California fertility specialist Dr. David Adamson. “While it is absolutely true that the birth defect rate and the abnormality rate is higher in twin pregnancies compared to singleton pregnancies, we still have to remember that the vast majority of twin pregnancies end up with two healthy babies,” he said in an interview. “That is not to say that we should be trying to get twins because we shouldn't—but we cannot make the argument that all [twin] pregnancies turn out as a bad outcome, that is absolutely not true.”
Educating patients about the risks of twin pregnancies can decrease some but not all interest in transferring more than one embryo, reported Dr. Ginny Ryan from the University of Iowa Hospitals in Iowa City. Previous work by her group has shown that IVF patients are three times more likely to desire twins, compared with a fertile population (30% vs. 10%).
In a new study, her group surveyed 120 patients waiting for IVF about their knowledge of fetal and maternal risks associated with twin pregnancies and then gave them an educational session about these risks. Although 30% of the group indicated a desire for twins prior to the educational session, this number dropped to 14% after the session. And whereas 78% of the group wanted a double-embryo transfer before the educational campaign, this dropped to 39% afterward, she said.