Ensuring Your Baby Will Be Healthy: Embryo Screening Test Gains in Popularity and Controversy; Choosing a Child's Gender

Amy Dockser Marcus
The Wall Street Journal
July 25, 2002

At 39 years old, shortly after his son, Jarred, was born, Jeffrey Sowers was diagnosed with myotonic dystrophy, a common type of muscular dystrophy. The Sowers had been planning on trying to have another child—until doctors told them there was a 50% chance their children could get the debilitating disease too.

"After that we figured that Jarred would be an only child," says Melanie Sowers, a 38-year-old accountant. "It wasn't worth taking the risk that our children might get sick."

Then the Sowers, who live in Temecula, Calif., found out about a medical procedure that could potentially ensure that any future child they had wouldn't get their father's disease. Called PGD, or preimplantation genetic diagnosis, the technique requires couples to conceive through invitro fertilization, a common procedure used to combat infertility that unites egg and sperm in a laboratory. But before implanting the resulting embryos in the woman's womb, doctors test a cell from each of them. They place only embryos that are free of the disease in the woman's uterus.

PGD, introduced a little over a decade ago, is starting to boom and some doctors say it could, in time, become a common -- albeit hugely expensive -- method of prenatal screening. Over 40 centers in the U.S. and abroad now offer the procedure, and over 300 children have been born through the method world-wide. At the Institute for Reproductive Medicine and Science of Saint Barnabas in Livingston, N.J., one of the major PGD centers in the U.S., the procedure was done 400 times last year. In recent years, the clinic has reported a 50% annual increase in cases. Shady Grove Fertility Centers, a large Washington, D.C., area based infertility clinic, started its own PGD program this month.

"Soon PGD will be used as regularly as amniocentesis now is," predicts Santiago Munne, the PGD program director at Saint Barnabas.

But the technique is increasingly being used for other, far more controversial, screenings. It has been successfully employed to find an embryo with matching bone marrow to donate to a sick sibling -- meaning that otherwise healthy embryos had to be discarded. But most upsetting to some people: PGD is also being used by couples who want to select the gender of their child.

"When we do patient surveys to see why people want PGD, many say they want it for family balancing" in terms of gender, says Dr. Munne of Saint Barnabas. (Saint Barnabas does gender selection only when there is a risk of sex-related diseases.)

The key to PGD's growing popularity is it is done before a woman is pregnant. Other prenatal tests are performed weeks, even months, into a pregnancy. If a problem is discovered, "you're already pregnant and have to decide whether or not to terminate the pregnancy," says Dr. Arthur L. Wisot, the executive director of Reproductive Partners Medical Group in Beverly Hills, Calif., and one of the Sowers' doctors. PGD eliminates such a wrenching experience, allowing a couple to choose which, if any, embyros to implant in the woman's womb.

Consequently, PGD is becoming an increasingly important tool for women trying to get pregnant after the age of 35, when the risks rise of having a baby with extra or missing chromosomes, which leads to birth defects or recurrent miscarriages.

The growing interest in the procedure comes despite some serious drawbacks. There is up to a 10% rate of error in detecting the genetic abnormality, which means it's not as accurate as amniocentesis or chorionic villus sampling, the two most common common prenatal tests. That's because PGD uses a single cell from the embryo so there is only a small amount of chromosomal and genetic material to examine; one test can't examine every chromosome or screen for every disease.

It also comes at a much higher price tag than standard prenatal tests: anywhere from $2,500-$3,500 for the PGD test and as much as $20,000 more to undergo invitro fertilization with the healthy embryos. Some insurance plans will cover it; others won't.

Consequently, PGD is most widely used by couples who know they have a risk of Tay-Sach's disease, hemophilia, Gaucher's disease, sickle cell disease, thalassemia and dozens of other genetic conditions that are passed down through one or both parents.

But there are many additional people who might want to use PGD. Genetic counselors say the prevalence of these diseases is more common than people suspect. Everyone has a 3-5% chance of having a baby with some kind of defect. In countries where there is a strong social, religious, or economic preference for boys, such as India and Jordan, PGD is often used to ensure having a boy.

Even in the U.S., using PGD for gender selection is on the rise. Some centers, or doctors, will do the procedure for that pupose; others won't. At the Sher Institute of Reproductive Medicine, a fertility clinic whose main office is in Las Vegas, Nev., "We allow gender selection for family balancing," says Dr. Geoffrey Sher, who heads the clinic. "If someone has three girls and they want a boy, we say sure." But he says the clinics will only allow gender selection for the sex that the family does not already have.

Before PGD is performed, a woman needs to take drugs that stimulate the production of her eggs and undergo surgery to remove them. Then one of two procedures is done, depending on what conditions pose the highest risk. The geneticists may examine two small cells from the ripening egg called polar bodies, which are removed from an opening in the covering of the egg and analyzed for chromosomal or genetic conditions. In other cases, the embryo itself is analyzed by making an opening in the covering of the embryo during the third day of development and removing one of the embryo's 8-10 cells.

Given how arduous the process is, most of the people using PGD are still like the Sowers, who don't care whether they have a boy or a girl but urgently want to avoid passing on a genetic disease to their children. Ms. Sowers has undergone the procedure two times, but she failed to get pregnant.

The couple plans to use PGD for any further attempts to conceive a child. Meanwhile, they still don't know the fate of their son, Jarred. On the advice of their neurologist, they aren't going to have him tested for mytonic dystrophy at this stage and so far he is showing no symptoms of the illness.

But their experience with PGD has made them realize the precarious odds of having a healthy child the conventional way. The first time they did PGD in February, they learned that eight of the 13 embryos they created had the disease; the second round, in June, resulted in two affected embyros out of five, and a third that stoped growing in the Petri dish.

"I was surprised at those statistics," says Ms. Sowers. "It scared me again for Jarred."

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Some Clinics That Offer PGD

-- The Institute for Reproductive Medicine and Science of Saint Barnabas
Livingston, New Jersey; www.sbivf.com

-- Molecular Medicine and Genetics at Wayne State University
Detroit; www.wayne.edu

-- Reproductive Genetics Institute
Chicago; www.reproductivegenetics.com

-- Shady Grove Fertility Reproductive Science Centers
Maryland; www.shadygrovefertility.com

-- Sher Institute for Reproductive Medicine
Las Vegas, Nevada; www.haveababy.com

Source: the clinics