Are IVF Twin Embryos a Risk?

pregnant woman peering at baby bump

The end goal of infertility treatment is pretty simple: to have a healthy baby. And while the prospect of having twins may seem attractive, that reality is that a multiple gestation greatly increases the risk to both the mom and babies.

Because the cost of fertility treatment is high and is not always covered by insurance in full, patients and even some physicians often consider transferring multiple embryos in an attempt to increase the chances of getting pregnant. And while stricter guidelines for embryo transfer have been successful at reducing higher order multiples (triplets or more), “the next hurdle is how do we reduce the twin rate while maintaining the same pregnancy rate?” says R. Stan Williams, MD, past president of the Society for Assisted Reproductive Technologies (SART), and professor and chair of the Department of OB-GYN at the University of Florida.

Patients, however, often tend to not see the risks of being pregnant with two. Some couples strongly want to transfer two embryos or actually desire twins.

The Risk of Multiples

Fertility doctors and patient advocates are working to educate patients about the serious health risks and high costs of having more than one baby at the same time.

“We have to do a better job educating patients about the health risks—they are not getting these messages,” says Barbara Collura, executive director of the infertility patient advocacy group RESOLVE. “They are being told it by their doctor as part of the informed consent process. But reproductive endocrinologists—you can ask any single one of them if they ever get pressure from the patients to transfer more than the required guidelines state, and they will tell you ‘yes, every day.’”

Women who are pregnant with twins are at much higher risk for pregnancy complications, including:

Premature birth: About 60 percent of twins are born prematurely at an average of 35 weeks.

Low birthweight: More than half of twins are born at less than 5 ½ pounds. Low birthweight babies, especially those born before 32 weeks and/or weighing less than 3 1/3 pounds, are at increased risk of health problems during the newborn period, as well as lasting disabilities such as mental retardation, cerebral palsy, and vision and hearing loss.

Cesarean section: Women who carry multiples may be more likely to need Caesarean sections, which may require a longer period of recovery and at times can increase the risk of hemorrhage during and after delivery.

Twin-Twin Transfusion Syndrome (TTTS): About 10 percent of identical twins who share a placenta develop TTTS, which occurs when a connection between the two babies’ blood vessels in the placenta causes one baby to get too much blood flow and the other too little.

Pre-eclampsia: Women expecting twins are more than twice as likely to develop pre-eclampsia, which is a combination of high blood pressure, protein in the urine, and generalized swelling that can be dangerous for mother and baby.

Gestational diabetes: This pregnancy-related form of diabetes can cause the baby to grow especially large, increasing the risk of injuries to mother and baby during vaginal birth. Babies may also have breathing and other problems during the newborn period.

Single Pregnancy is Safer

Being pregnant with one child is safer and presents the greatest chances for an optimal outcome. A 2016 study published in BMJ (British Medical Journal) found that women who undergo IVF are almost five times more likely to give birth to a single healthy baby following an elective single embryo transfer (eSET) when compared with women who choose to have two embryos transferred. In addition, the eSET appeared to significantly increase the chances of carrying the baby to full term (37 weeks).

With medical advances, assisted reproductive technology (ART) has come a long way from the early days of transferring multiple embryos in the hopes of getting just one to implant. Modern techniques such as blastocyst stage culture and transfer are maximizing pregnancy rates and minimizing the risk of a multiple pregnancy. By growing embryos for five days in the laboratory and enabling them to reach the blastocyst stage of development, fertility doctors can better determine which embryos have the greatest likelihood of implantation.

Research has shown that success rates for single embryo transfer vs. double embryo transfer are similar in certain circumstances. “In a favorable patient who is having a blastocyst (Day 5 embryo) transfer, one blastocyst is an equivalent pregnancy rate to two,” Dr. Williams says.

But some couples have difficulty accepting these studies, according to Michael A. Feinman, MD, Medical Director of HRC Fertility in Southern California. “They intuitively feel that the second embryo must hedge their bet. Also, input from friends and former patients often affects their feelings.”

The most recent guidelines on embryo transfer from the American Society for Reproductive Medicine (ASRM) and SART are very individualized. For example, for a woman under age 35 who is in the favorable category, the recommendation is to transfer one embryo, regardless of embryo stage.

“The big advantage of the American system is we can look at shades of gray,” Dr. Williams explains. “Depending on the patient’s age, the prognosis of the patient, and the stage of the embryo development, we can develop guidelines that are more flexible to meet the needs of the patient while trying to reduce the potential for multiples.”

One of the biggest obstacles in patient care is cost, says Collura. “We also know that patients tend to feel more pressure to transfer more embryos when they have pressures on cost—if somebody does not have insurance, and they only have $15,000, they may say, ‘Look, I only have this one shot. Transfer as many as you can.’”

Dr. Feinman has seen this many time, “Some [patients] think [having twins] is cost-effective if they are paying for their care: ‘Two for the price of one,’” he explains. “Sometimes it is hard to convince them that this is not true, since twins tend to cost much more than a frozen embryo transfer.”

“In Canada and much of Europe, the government will only cover IVF if the clinic performs single embryo transfers,” he continues. “In some countries, if a non-identical twin occurs, the clinics have to pay back the government. In the U.S., insurance companies have abdicated their moral right to affect the situation by refusing to cover IVF. Ironically, they spend a lot more money on the multiple births created by IVF than they would if they covered it and helped regulate it. If our government or insurance companies ever wake up and realize this fact, there might be a move toward increased coverage with increased restrictions accompanying this coverage.”

Collura says that patients make better health care decisions when the cost pressure recedes. “There’s a lot of data out there about insurance coverage in mandated states and the reduction of multiple births in those states.”

A study by Yale School of Medicine researchers published in Fertility and Sterility found that the 15 states that provide insurance coverage for infertility saw significantly lower multiple birth rates. In 2005, it was estimated that the economic impact of preterm birth was $26.2 billion nationally.

RESOLVE has worked with Shady Grove Fertility, a Maryland fertility clinic, to produce a patient education video about the risks of multiples. The video is based on a true patient story and a letter the patient wrote to Shady Grove after she had twins born at 25 weeks, specifically asking Shady Grove if they could use her story to help educate others about the risks of premature birth. The video describes how one twin had intestinal surgery and how both spent approximately seven months in a hospital.

“I am hoping that hearing a person’s story about her own experience and providing some data is going to be effective,” Collura says. “Our idea is for this to be available to any fertility clinic, anywhere in the United States. “Whatever I can do to help that patient know more and be better educated, I’m going to do that.”

SART developed a national consent form for fertility clinics to use that gives very detailed risks for pregnancy with multiples. In addition, ASRM is in the early stages of developing a video about the risks of multiples, according to Dr. Williams. “We are very interested in reducing multiple pregnancies.”

Dr. Alan Copperman is a board-certified reproductive endocrinologist and infertility specialist with a long history of success in treating infertility and applying fertility preservation technologies. He serves as Medical Director of Progyny, a leading fertility benefits management company, and co-founded and serves as Medical Director of RMA of New York, one of the largest and most prestigious IVF centers in the country. Dr. Copperman is also the Vice Chairman and Director of Infertility for the Icahn School of Medicine at Mount Sinai, and Chief Medical Officer of Sema4, a health information company. Dr. Copperman has been named to New York magazine’s list of Best Doctors 17 years in a row. He has been recognized by his peers and patient advocacy organizations for his commitment to patient-focused and data-driven care. He has published more than 100 original manuscripts and book chapters on reproductive medicine and has co-authored over 300 scientific abstracts on infertility, in vitro fertilization, egg freezing, ovum donation, and reproductive genetics.