The answer will depend upon how a person views predicting the future. Oh, that again… just when you think you’ve got it figured out, someone changes the rules. Statistics actually provides a method of predicting the future. Not quite as snazzy as a crystal ball, but a lot more accurate. The ‘numbers’ can guide you to the best way to use all of this information that is at your fingertips and actually help yourself.
So how does statistics work? The most common misconception about statistics is that they will tell a person what will happen. Actually, they tell a person what might happen and how likely the event is to happen. Patients frequently ask whether a prediction/statistic applies to them. Yes it does, but that is not what a person wants to know. Most people want to know what will happen to them as an individual. Statistics speak to people as a whole, not the individual. If a physician tells a person that the chance of having an infection or a bleeding complication from an egg retrieval is about 3 in a 1000, that is reassuring…unless of course you are one of the three who had the complication.
Making smart choices in medicine rests upon the use of predictions. A prediction makes a statement, usually in the form of a percent or odds such as one in ten. Both types of predictions require two numbers; numerator and denominator. A percentage is nothing more than one number (numerator) divided by another number (denominator) expressed as a percentage. Unless you know both the numerator AND the denominator, a statistic is meaningless. Knowing the denominator frames your information into likelihood…or not. Think of it as the lottery. 1000’s of people have won a lottery…sounds like a good bet, no? Unless you realize that billions have played. It is the stories that are told, numerator only, that warp the statistics, and often the hopes and dreams of the people reading them. A seemingly great story of a pregnancy that was achieved against all odds seems like it could be YOUR story, until you put it into the context of the number of people who have attempted, and failed, to make it their story as well. Consequently, the horror story bandied around on any given day regarding risks from Infertility or any other procedure, may send its reader running…until/unless that number is put into context (by reporting the denominator as well) and the Unlikelihood of this occurring is realized. The point to remember is that rare events, whether good or bad, are actually predicted by statistics so rather than being wrong they are, in fact, correct.
Statistics allows a person to make a risk-benefit determination. What is my chance of being pregnant from the cycle of IVF versus what is the chance of significant harm from IVF? For example, there is actually a death rate for doing egg retrievals for IVF. It is quite low and perhaps incalculable but some estimates are 5/1,000,000. What most people don’t consider is that there is also a death rate from being pregnant. On any given year in the USA, the death rate varies around 16/100,000 live births. In 2008, the motor vehicle fatalities were 18/ 100,000 registered drivers. Interesting but let’s get back making a smart choice about getting pregnant!
So let’s say that you were just born and had never seen a coin nor bet on a coin toss. A somewhat nefarious fellow shows you only one side of a penny and all you see is Lincoln. He says he’ll flip the coin in the air and he bet’s you a buck that when it lands Lincoln won’t be on the coin. Again, you we just born so being somewhat gullible you think this is a good idea and you bet him the buck. He tosses it and “voila” it’s Lincoln- you win. Bolstered by your success, when he says he’ll make the same bet if you toss it again, you eagerly take the bet. But wait- what is this? A picture of some stupid memorial? Where did that come from? Now he wins and you learn an important principle. The coin has two faces and a smart choice would have been to have inspected the coin to begin with and determined what was on the other side. Furthermore, tossing the coin does not always guarantee that it will land on Lincoln. So what about a third toss? Should you take that bet? Here is where statistics can help you make a smart choice.
Anyone who understands a coin toss can understand the important points from using statistics to help make a decision. The problem with mass communication and overwhelming data is trying to determine the accuracy of a prediction. For example, suppose you are browsing the web and a 42 year old lady says she got pregnant on her fifth try at IVF. You are 42 and trying to decide if you should do IVF at all. The first problem with a personal story on the web is that it is impossible to tell if the story is accurate or even if it is true. Just because someone put it on the web does not make it factual. But let’s suppose the above is true. What is the chance of a 42 year old person getting pregnant and how fast should it happen? That information is available. A 42 year old just starting to try to get pregnant has less than a 50% chance of being successful. If the woman can get pregnant, it happens quickly, usually within the first 6 months of trying. The longer a woman tries to get pregnant and is unsuccessful, the less the chance that she can conceive.
So assume that you have been trying for six months and you are not pregnant. You consult an REI and that person suggests moving straight to IVF. Seems a bit aggressive on the first go? Now it’s time to figure out the odds of achieving a successful pregnancy on the first try for a 42 year old woman with a normal evaluation (semen analysis for partner OK, uterine cavity OK, ovarian reserve [hormone testing] OK). National data suggest that it would be somewhere around 10%. What would be the chance if you did nothing? That estimate is somewhere around 1-3%. Other choices like clomid or an Insemination protocol are probably not better than IVF and most likely somewhat less successful. With this information, our 42 year old opts for IVF…and doesn’t get pregnant. The story about the fifth time being the charm looms in her mind. Yet, doing a cycle of IVF was not as easy as she thought it was going to be, her response was not great and the quality of the two embryos that formed was only average. Oh, and she wants to be pregnant now. So what about a second cycle of IVF? The chance is still about 10%. Second cycle, not a great response and still no pregnancy. The thought of a third try is almost overwhelming. It is worth it? Use statistics!
What are the options? Do nothing, do another cycle of IVF, do a cycle of IVF using donor eggs or adopt. You already know that the chance of getting pregnant on your own is exceeding small- OK not zero- but really, are you feeling that lucky? Donor oocyte cycles are somewhat successful with a delivery rate around 50% for the first try. Adoption is an option but it is expensive and neither you nor your partner has any genetic input into the child, nor do you have the chance to carry the baby and deliver the child. On the other hand, when done properly adoption has a very good “success” rate. How about that third cycle of IVF? Estimates will vary but the literature that does exist suggests that after two tries for women between the ages of 41 and 43, the success for the third try at IVF is very low and perhaps not different from doing nothing. Knowing the statistics puts the options in perspective. It does not help make the decision because a lot of factors go into a decision about what form of treatment to use, but at least statistics allows a person to rank the options by the likelihood of success.
In the end, the best you can do is to gather reputable information, combine the outcomes, add the things that are important to you and go for it. The use of statistics can give you the best chance of getting what you want. All statistics comes down to the concept of the coin toss so don’t let the numbers scare you. Use statistics to achieve success.
Dr. Rinehart is a Founding Partner of Reproductive Medicine Institute (www.reproductivemedicineinstitute.com) with six board certified specialists in the field of reproductive endocrinology and immunology including the area of recurrent miscarriage, along with the treatment of endometriosis, in seven locations throughout Chicagoland.
