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Age & Down Syndrome Risk


Okay, so hopefully I haven’t, but I’m guessing I’ve raised some concerns about aneuploidy. You might be wondering, what’s my risk— my personal risk? What’s happening with that, right? You start thinking about this. Well, if I were to draw a graph and talk about risks like I have here, I’ve got risks going up the one way one out of a thousand, one out of 10, one out of 100, okay. And then going across the bottom I have some numbers there. Anybody guess what those numbers on the bottom are? Ages. Ages. Yeah. Whose age? The parents, the mother. Mom’s age. Yeah it’s actually mom’s age. Moms probably want to blame it a little bit on dad, but it’s mom’s age. That’s the issue that’s related to chromosome number problems. Why do you think it’s mom and not dad? That’s not fair, right? Uh-uh. Any guesses? Because of the eggs. Yeah, because of the eggs. How long have you had your eggs? Since birth. Yeah. You’ve had them since birth. You’ve had the same ones. In fact, you had the most eggs you’ll ever have in your life when your mom was 20 weeks along with you. Wow. By the time you’re born, you have fewer and then if you’re lucky — about 15, if you’re unlucky — about 11, right, every month you start using some eggs. And that’s the menstrual cycle. And then that keeps happening so that you’re using up those eggs until they’re all gone. That’s about 50ish on average in this country, and then you go through menopause. Whereas the daddy — millions and millions of new sperm are made everyday. Right? So they’re always turned over, plus they’ve got a long way to swim. Right? The good ones make it and the bad one’s don’t very often. Does that make sense? So it’s the mother’s age.

Now, when you think about mother’s age in risk of chromosome problems, how many of you think the risk goes like this? It’s going along and all of a sudden at 35, boom, it shoots out and goes through the roof. Right? Have you heard that? I’m 35 and now suddenly I’m at higher risk. Have you ever heard that? Yes. Yeah, I have friends who say, “You know I’m going to turn 35 next year, I’ve got to hurry up and have a baby.” Well, really it’s not like that. The real risk goes like this. It goes up slowly. Now that’s a log scale so what that means is it goes up faster the higher you get. But the reality is there’s no sudden change between 34 and 35, or 35 and 36. It just is rising. So what’s going on at 35? Makes you wonder doesn’t it? Why people have raised that as a question.

Now remember I said earlier we’re going to look at The Purple Book for a minute. If you can turn to page 147 and 148, there’s a table in there and it looks a little bit like this. What this table is doing is putting mother’s age and then looking at risk of chromosome problems, Down syndrome in the one column, and then all chromosome problems in the other. That’s a little bit different than the slide show. The slide one is showing what the risk of chromosome problems is at 16 weeks and what the risk is at 40. Now they’re a little different because higher rates of miscarriage in babies that are abnormal compared to normal.

Now let’s do this, think about how old you’re going to be at your due date. Hopefully everybody knows your due date. Do take your best guess if not. Think about your age. And then look on that table, and look at your age and then look at your specific risks and it will say one out of something. Okay. And then you can take that risk, and if you get your passport there’s a place in here on the inside where you can actually write down your age specific risks. So on the bottom left fourth of this page, it says your age-based risk for Down syndrome. DSR is your Down syndrome risk and all aneuploidy is that other risk that’s beside there on the table. Okay? So everybody look at that and write down your age specific risks for chromosome problems and Down syndrome. I’ll help you, if I lose you.

Good. Okay everybody got it. Uh-huh. All right now, I’m going to say something that I know you guys all know, but just to be clear. One out of 10 is 10 percent, right? One out of 100 is one percent. So in the case of something bad, it’s better to be one out of 1000 than it is to be one out of 10, right?

Okay. Let’s talk for a second about this whole 35 question. And here’s a question, one more question for you guys. Do you think more babies with Down syndrome are born to woman older than 35 or younger than 35? Older? Younger? Ah younger/older. Good question, here’s another hint for you before I let you finish. Here’s the number of babies born at each maternal age. Wow. There’s a lot more babies born at 25, 26, then there are at 36, you know 25, 27 then 36, 37 right? So it’s kind of a little bit of a trick question, because if you take the total number there are actually more babies with Down syndrome born to women younger than 35 because there’s so many more babies born to women younger than 35. But the age specific risk goes up the older you get. Okay. So my point there is it can happen to anybody but if you look at the numbers it doesn’t happen to most people.