GENETIC TESTING

AMNIOCENTESIS
The most common type of genetic screening is done using amniocentesis. In this procedure, a needle is inserted in a pregnant woman's abdomen and a sample of amniotic fluid is taken. Fetal cells will be present in the fluid (we are all just shedding cells all of the time, just like animals shed hair - no wonder my house isn't clean!) and these cells will be subjected to a chromosomal analysis. By looking at the chromosomes, many disorders can be identified. The most commonly detected is Down syndrome, which is also known as trisomy 21, because it is caused by having three of the 21st chromosome. As mentioned in Appendix A in your text, the risk of Down syndrome increases dramatically after age 35, which is a major reason that many physicians encourage anyone over 35 to have an amniocentesis.

If amniocentesis can identify disorders before birth, why doesn't everyone have one?

There's the fact that these are not cheap. Mine cost around $650. The more important reason, though, is that this is not a risk-free procedure. Think about it, you are taking a large needle and inserting it into the stomach of a pregnant woman. Does this sound like a bad idea to anyone besides me? The risk of miscarriage is about 1 in 200.

Why do people have an amniocentesis, then?

To be flat out honest with you, most people have them because they do not want a child with a dability and are going to abort the fetus if it is determined to be defective. Van der Zanden (1993) in his book Human Development cites a study that examined 3,000 prenatal diagnoses and found that in the 113 cases that an abnormal fetus was identified, 106 were aborted at the parents' request. Incidentally, nothing is fool-proof. In these 3,000 cases, there were six where an incorrect diagnosis resulted in misleading information to parents. The result was two health fetuses were aborted and four fetuses with birth defects went undetected and were born. Six out of 3,000 is not bad odds, but it is not zero.

MY AMNIOCENTESIS STORY or

IT'S ALL DIFFERENT WHEN IT'S YOU

Okay, I am a well-educated person, I have been teaching developmental psychology for years, including the section on amniocentesis and genetic testing, which mentions the fact that 94% of the time a fetus is identified as defective it is aborted. Then, all of a sudden, at age 38, I find out that I am pregnant. This isn't unwelcome news. After all, we had been talking about having a baby pretty soon after we married. I had always wanted more children, but my husband had been in a serious accident, which didn't make it seem like a good idea, and then he had died, which sort of ended the possibility. My new husband was 42, had never had children, and really wanted a baby. What could be wrong?

Well, at 38, the chances of having a child with a genetic defect, particularly Down syndrome, is much higher than it is at 28 (when my last baby was born). I am the kind of person who worries about everything that could possibly happen, so I decided to have an amniocentesis because I knew that most of them come out perfectly fine (96%, in fact) and it would greatly ease my mind over the next few months to know that the baby was all right.

First, I had to sign a consent form, and, on the form it said, "I have decided that I will have an abortion if the baby has Down syndrome". Actually, I had decided no such thing. The only possible explanation I could think of for this odd requirement is that some group had opposed amniocentesis on the grounds that it would encourage mothers to have abortions, so the lab and physician had decided that a way to avoid this controversy was to only offer amniocentesis to mothers who had already decided to have an abortion if the test results were unfavorable. At that point, I hadn't made up my mind, but I figured, what the heck, I would sign the paper. They couldn't MAKE me have an abortion if I decided not to. Then I went home to wait for three weeks until the amniocentesis was scheduled. (They really made sure I had time to think it over. My friend, who was 42 when her second child was born, decided not to have an amniocentesis because she said, "We were going to have him no matter what, so there was no point.)

One of the things I was not prepared for was how late in pregnancy an amniocentesis is performed. Your textbook says that most physicans prefer to do an amniocentesis at 18-20 weeks. Then, it is another week to ten days before the test results are available. Think about what that means. Quickening - the movements of the fetus which are felt by the mother, begins early in the fifth month, sometimes earlier. So, by the time you find out if the fetus has some type of disorder, you have already felt the baby moving inside of you for a week or two, sometimes more. Although the fetus will not be able to survive outside the womb for another eight weeks or so, this is not just a cluster of cells. The fetus is about ten inches long and weighs around a pound. All of the organs have developed, internally and externally, right down to the fingernails and toenails.

By the date of the appointment, I still had not decided what to do. My husband said,

"You know, if we have a baby who is severely handicapped, we probably won't be able to have another baby. Four kids is hard enough, but when one of them requires a lot of extra time and money, it just seems like it would be too much to have a fifth one. I really would like to have one healthy, normal baby."

My oldest daughter, who is fifteen, also gave her own, unsolicited opinion, one day,

"You want to hear my opinion? Well, you're going to anyway. The way I figure it, you two are going to die sooner or later because you are old, let's face it. You're almost 40 and Dennis is over 40. So if you have a handicapped baby that can't take care of itself, I am going to end up taking care of it. This may seem like an awful thing to say, but when I am 35, I want to be raising my own kids, not some handicapped kid that you had. I mean, if Ronda or Jenn (her younger sisters) got hit by a truck and got brain damage, I would take care of them. But, I think it is pretty selfish of you to have a baby that you know someone else will have to end up taking care of.

One of the things they don't tell you about amniocentesis is that it hurts, not nearly as much as having a baby, but it hurts nonetheless. What do you expect, really, when some person jabs a long needle into your stomach? The obstetrician said, "It shouldn't hurt, it must be because you are so thin." My friend, who is somewhat overweight, was told by her physician "Oh, it's not supposed to hurt, it must be because you are so heavy." It hurts.

    So, then, we were told, it would be 7-10 days before we got the results back. Personally, I thought it was very important to decide whether or not we were going to keep the baby BEFORE we knew. I don't know why I thought that, maybe just because, if she ever asked me "Mom, would you have had me no matter what?" I could answer, "yes".
    In the end, that is what I decided, regardless of anyone else's opinion. As I told my other children, "I took what I got when the three of you were born, and I just can't see saying with this baby, 'If it's not perfect, just kill it!' "
So, we, or rather, I decided to have the baby. Then, of course, there were still several more days until we found out the test results. I was beyond nervous. I called the doctor's office every day. FINALLY, nine days after the test, I received a call from the obstetrician. He just wanted me to know that everything was fine. We were having a little girl, and every test had turned out fine.

    An ultrasound is a much less precise measure than an amniocentesis, with no risk for the fetus. Sound waves are bounced off the fetus, just like the sonar used by submarines is used to 'see' the shape and size of objects under water. The shape and size of the fetus can be seen, and any obvious malformations, such as missing limbs. Ultrasonography also detects multiple fetuses. This is how Bobbi McCaughey found out she was going to have septuplets. While it was common when I had my older children, for women to be carrying twins, or even triplets, and not have any idea until the actual birth, this is seldom the case any more, at least among women who receive prenatal care.
    When I had my last baby, eleven years ago, ultrasound was only used in the case of suspected problems. These are now used routinely. In fact, living on the yuppie westside of Los Angeles county, there is even a physician who advertises that he will schedule sonograms on weekends and give a you a video and photographs of the fetus (for a large fee, of course). Sort of like your first baby pictures. As your textbook mentions, this ability to see the fetus before birth may facilitate parental bonding. We had a sonogram a couple of days after the amniocentesis results came back. My husband and two daughters came to watch. We could see her moving around, see her arms, head, hands, legs, and see her jump when my youngest daughter leaned close to my stomach and yelled, "Hey, anybody in there?" Response to loud noises is innate (loud noise is an unconditioned stimulus, if you remember your classical conditioning theory). Yes, we did get pictures, which my husband took to scan into the computer so he could put them on his home page for relatives around the country to see what our baby looked like. (Like any other sonogram at four and a half months, I would imagine). What struck me as rather eerie about the whole thing was that, if the tests had turned out abnormal, most people would have had an abortion scheduled for this day. Strange, isn't it?

While this may sound as if I am saying people who have an abortion following an amniocentesis are heartless, I really don't think that. Raising any child is an extremely difficulty task. Raising a child who is disabled is even harder. A woman I interviewed for a research project commented on her experience having a severely disabled child, "People say God must have picked you specially to cope with the challenges of this child. #$%^! No one wishes and prays for a handicapped baby when they are pregnant. No one."

All I am saying is, it is one issue when you discuss genetic testing and the decision to have an abortion as a hypothetical issue, and a whole different story when it is you.

FTHE WORLD WIDE WEB EQUIVALENT OF A FIELD TRIP E
Click below to go to a really cool site on genetics. Before you do, I might mention that the pictures on the web pages sometimes take forever to show up, so you may want to wait or just read the stories and go on. Be sure you at least read the one entitled "Genes of Life and Death", as well as any others that strike you as interesting. ALSO, you need Java and a plug-in called shockwave installed on your computer if you are going to view the animated sections. If you don't have these (or don't know if you do), don't worry about it. The animations are kind of fun to look at but not at all essential to understanding the information. You click on the pictures to make things happen in the animation. (If you click on 'done' or 'next ' in the "Cytoplasmic Cell Donation", it will show you what happens next. If you click on specific body parts in "The Manmade Man", it will zoom in to show more detailed information on that body part. Since these pages weer developed by the Public Broadcasting System, there is not a link back to this page, so you will have to click on the back arrow in the top left of your screen to get back here.

All right, already, click here and go to the innovations web site.

Click here to do the third assignment.

Click here to learn all about the graphic details of pregnancy and birth.