This summer Louise Brown, the world’s first “test tube” baby, celebrated her 38th birthday as a mother of two naturally conceived children. In the decades since Ms. Brown’s celebrated birth, the techniques of in vitro fertilization, or I.V.F., have improved tremendously, resulting in an estimated five million babies worldwide born to couples unable to conceive on their own.
The many happy stories about couples whose families were enhanced by I.V.F. tend to overshadow the many more failures rarely talked about, creating the impression that the procedure is far more effective than it really is.
At the same time, the techniques usually used have led to a rash of multiple births — more than 40 percent of all I.V.F. deliveries in the United States are of twins or higher — because doctors commonly transfer two or more embryos in hopes of achieving a successful pregnancy.
As Dr. Allan Templeton of the University of Aberdeen and Aberdeen Maternity Hospital in Scotland reported, “in the United States, between 1980 and 2001, a fourfold increase in triplets and high-order births was documented, as was a 60 percent increase in twin births.”
Fast-forward to 2013, the latest year for which comprehensive data on I.V.F. births in the United States became available. More than 60,000 babies — about 1.6 percent of all infants born here — were conceived through I.V.F., and 41.1 percent of all I.V.F. deliveries were multiples, “directly attributable to the common practice of transferring multiple embryos to the uterus to enhance pregnancy rates,” Dr. Abigail C. Mancuso and colleagues at the University of Iowa Carver College of Medicine and at the Centers for Disease Control and Prevention reported this summer in Fertility and Sterility.
It may surprise many to know that Louise Brown was born following the transfer of just one embryo that had been fertilized externally and transferred to her mother’s womb. And contrary to current practice, her mother had not been treated with drugs to induce the production of a slew of eggs — just one egg was used.
Of three women I know who became pregnant through I.V.F. since 2000, two had twins and one had triplets (although three other friends came away empty-handed, financially and emotionally drained, each after several attempts at I.V.F.). An estimated 36 percent of recent twin births and 77 percent of births of triplets or more in the United States resulted primarily from medically assisted pregnancies.
The creation of an instant family of four or more may sound wonderful to couples who struggled for years to conceive and to older women nearing the end of their best childbearing years. But as “cute” as twins and triplets may seem, multiple pregnancies can be fraught with complications that compromise a successful outcome and the health of mothers and their babies.
Most of the nearly 500 fertility clinics in this country are private profit-making facilities, and as I.V.F. grew in popularity, those seeking to attract patients by advertising high pregnancy rates began inserting multiple embryos.
However, the new study of American I.V.F. clinics by Dr. Mancuso’s team revealed that transferring a single embryo in women younger than 38 resulted in a marked reduction in multiple birthrates but no decline in live birthrates.
Although transferring multiple embryos could result in more live births, many of those babies are born prematurely and spend weeks or months in a neonatal intensive care unit. Some die hours or days after birth, and a significant number of surviving infants emerge with lasting physical and developmental scars like cerebral palsy.
Their mothers are also more likely to develop pregnancy-related complications like miscarriage, high blood pressure, gestational diabetes, pre-eclampsia, premature labor, placental abnormalities, cesarean delivery and prolonged hospitalization.
In recent years, professional organizations concerned about the safety of multiple gestations and births for both mothers and their babies have been recommending that only one, and at most two, healthy embryos be transferred at a time. The benefit of this advice is already apparent: The rate of I.V.F. pregnancies that resulted in multiple births dropped to 22 percent in 2014 from 50 percent in 2009.
In the latest advisory in August, the American College of Obstetricians and Gynecologists stated that “electively” transferring just one embryo at a time can achieve high pregnancy rates with less risk to babies and mothers and “a drastic reduction in multi-fetal pregnancy” (twinning can still sometimes occur when a single embryo splits in utero, as happens with naturally conceived identical twins).
The college’s new guidelines point out that the costs of I.V.F. — often in the range of $20,000 a cycle — can prompt patients to request multiple embryo transfers in hopes of completing a family with one treatment cycle. Unlike in countries with national health systems, in the United States few insurers and no government insurers cover the procedure (except in some cases for veterans injured in service), which basically restrict its availability to affluent patients.
However, insurance economics are penny-wise and pound-foolish. As long ago as 1998, Swedish researchers reported that, in achieving a successful pregnancy, “one embryo transfer is more cost-effective than two embryo transfer when all the costs associated with multiple gestations are taken into account.”
Furthermore, if a patient has more than one healthy embryo available for transfer, the extras can be frozen and used later at a much lower cost, Dr. Mancuso said in an interview. In a study at her hospital in which prospective I.V.F. patients were “educated correctly” about the risks of a multiple pregnancy, more chose a single embryo transfer.
Unfortunately, prospective I.V.F. patients who check clinic websites can be easily misled, said Dr. Mark V. Sauer, who ran an I.V.F. clinic at Columbia University’s Center for Women’s Reproductive Care for 21 years.
Consumers can be easily overwhelmed by the available data and be unable to distinguish between good medical practices and a sales pitch, he said. Most reliable is the information gathered by the C.D.C., reported by 467 clinics under federal law with serious penalties for inaccurate data. The latest is a 76-page report with easily interpreted graphs, the 2013 Assisted Reproductive Technology National Summary Report.
“There’s a tremendous focus on getting patients pregnant, and they tend to downplay the risks of a twin pregnancy,” Dr. Sauer said. “A clinic’s pregnancy rate does not necessarily reflect the live birthrate. We all consider twin pregnancy to be an undesirable outcome that can be completely avoided if doctors and patients agree that single embryo transfer is the right thing to choose.”