"50% of women get pregnant while on contraception"

[melrich]

No, that is incorrect. No matter how many times you have sex---one time or 100 times--your odds of getting pregnant are the same.

 

No it's not incorrect. Yes your odds are always the same but the more you do it the more likely you are to become pregnant.

 

Think about flipping a coin. The odds of heads or tails are 50%...every time you flip.

 

If you flip it once you are 50% likley to get a tail. If you flip it 100 times you are far more likely to hit a tail on one of those flips.

 

The more you do something, the more likely you are to get a certain result even though each event the odds remain the same. Eventually one event is going to "prove" the odds.

[confusedgirly]

Ok you guys i'm sure about this. I don't know much about relationships but I definitely know my stats.

 

You don't have a 2% chance of getting pregnant each time you have sex. You have a 2% chance of getting pregnant over a year. (Of course, the more often you have sex, the greater your chances, but we're talking averages here.)

 

Now, if they continued the study for 20 years, there would be 40 pregnancies altogether for those 100 women. Thus, a 40% chance of pregnancy after 20 years.

 

I think you're wrong too. The pill doesn't get 'less effective' over time. You take it today for example and you have sex you have a 2% chance of falling pregnant. You take it tmorrow and have sex again, you have 2% chance again and so on and so forth.. your body just doesn't say suddenly 'oh hey, you've been on the pill for years now oops okay let's open a bigger window and up your chances of getting pregnant'

 

I dont think so .

[RayKay]

Ok you guys i'm sure about this. I don't know much about relationships but I definitely know my stats.

 

You don't have a 2% chance of getting pregnant each time you have sex. You have a 2% chance of getting pregnant over a year. (Of course, the more often you have sex, the greater your chances, but we're talking averages here.)

 

Now, if they continued the study for 20 years, there would be 40 pregnancies altogether for those 100 women. Thus, a 40% chance of pregnancy after 20 years.

 

Yes, it is 2% over the year (but you expose yourself to falling in that 2% each time you have sex).

 

But the data does not extrapolate that way. It would not be 40 pregnancies out of 100 women, it would be 40 pregnancies out of 2,000 women (20 x 100 women).

[Batya33]

When I started the pill at age 24 there was no such thing as "reminders" in a "phone" - we had land lines only, no answering machine and no gadgets for "reminders." I was pretty good at remembering to take it at the same time each day but it was a challenge while travelling for business etc. I never got pregnant but often used a backup method.

[confusedgirly]

No it's not incorrect. Yes your odds are always the same but the more you do it the more likely you are to become pregnant.

 

Think about flipping a coin. The odds of heads or tails are 50%...every time you flip.

 

If you flip it once you are 50% likley to get a tail

 

Well, who knows how many times i've had sex while on the pill in my life. On average about three times a week for four years and never once fell pregnant.

 

Am I a poster child for the pill or something?

[toshiba]

No it's not incorrect. Yes your odds are always the same but the more you do it the more likely you are to become pregnant.

 

Think about flipping a coin. The odds of heads or tails are 50%...every time you flip.

 

If you flip it once you are 50% likley to get a tail. If you flip it 100 times you are far more likely to hit a tail on one of those flips.

 

The more you do something, the more likely you are to get a certain result even though each event the odds remain the same. Eventually one event is going to "prove" the odds.

 

Actually, that's not true. Your odds are the same no matter how many times you flip the coin. It's the law of probabilities and there is extensive theory behind it.

 

Case in point: no matter how many times you play the lottery, your odds are still the same each time you play.

[melrich]

Well, who knows how many times i've had sex while on the pill in my life. On average about three times a week for four years and never once fell pregnant.

 

Most don't. And the heads / tail thing is a bit misleading as you are talking about "proving" odds of 50%. The odds with the pill are 1 in a 1000 or 1 in 500 depending on your data source. So most will not prove those odds.

[melrich]

Actually, that's not true. You're odds are the same no matter how many times you those things. It's the law of probability and there is extensive theory behind it.

 

That's right. I never said the odds changed. I said this was right,

 

So, if you have sex 100 times compared to someone who has sex 10 times, you are more likely to become pregnant.

 

That is probability. You said my statement was incorrect. But the more times you do something the higher the probability that you will prove the odds.

[leo_s84]

Ok you guys i'm sure about this. I don't know much about relationships but I definitely know my stats.

 

You don't have a 2% chance of getting pregnant each time you have sex. You have a 2% chance of getting pregnant over a year. (Of course, the more often you have sex, the greater your chances, but we're talking averages here.)

 

Now, if they continued the study for 20 years, there would be 40 pregnancies altogether for those 100 women. Thus, a 40% chance of pregnancy after 20 years.

 

Wow..no

 

If they continue the study for 20 years there would be 2000 women, not 100 (100 per year). So there would be 40 pregnancies (2 each year) but out of 2000 women!. So stats remain the same... Percentages are almost never cumulative in studies like this!!!!

 

If they used the same women on a course of 20 years, The same 2 women could be getting pregnant along all those years (statistically speaking) so 98% of those women wouldn't be pregnant. Your math is definitely flawed on this one.

[rocio]

Wow..no

 

If they continue the study for 20 years there would be 2000 women, not 100 (100 per year). So there would be 40 pregnancies (2 each year) but out of 2000 women!. So stats remain the same... Percentages are almost never cumulative in studies like this!!!!

 

If they used the same women on a course of 20 years, The same 2 women could be getting pregnant along all those years (statistically speaking) so 98% of those women wouldn't be pregnant. Your math is definitely flawed on this one.

 

That doesn't make sense because what you're saying is that you have the same chance of getting pregnant whether you have sex for 1 year or 20 years. That obviously can't be the case. (Of course, you have the same chance of getting pregnant EACH year, but you're doing it for more years...)

 

The only question is whether these are mutually exclusive events. In other words, can someone get pregnant in more than one year? The answer is yes and no. A woman cannot get pregnant while she is already pregnant (or directly after). However, a woman can get pregnant in, say, 2005 and then again in 2008. So, the probability is somewhere between:

 

a) P(p)*#years

or

b) P(p)*#years - P^# years

 

...where P(p) = probability of pregnancy in 1 year.

[toshiba]

That doesn't make sense because what you're saying is that you have the same chance of getting pregnant whether you have sex for 1 year or 20 years. That obviously can't be the case. (Of course, you have the same chance of getting pregnant EACH year, but you're doing it for more years...)

 

 

 

If someone plays the lottery for 20 years, does it increase their odds of winning?

[melrich]

That doesn't make sense because what you're saying is that you have the same chance of getting pregnant whether you have sex for 1 year or 20 years. That obviously can't be the case. (Of course, you have the same chance of getting pregnant EACH year, but you're doing it for more years...)

 

The only question is whether these are mutually exclusive events. In other words, can someone get pregnant in more than one year? The answer is yes and no. A woman cannot get pregnant while she is already pregnant (or directly after). However, a woman can get pregnant in, say, 2005 and then again in 2008. So, the probability is somewhere between:

 

a) P(p)*#years

or

b) P(p)*#years - P^# years

 

...where P(p) = probability of pregnancy in 1 year.

 

You are mixing your math.

 

The odds (assuming no variables) remain the same for each and every event. So the odds of you getting pregnant whilst on the pill from any one event are the same the first time you have sex as the 2000th time.

 

The probability that you will prove those odds increases with repetition of the event. It does not mean that you WILL prove it or that your proving will correlate with the odds.

 

But odds on a singular event do not accumulate. If you flip a coin 10 times and it comes up heads, the odds of heads or tails on the eleveth flip is still 50/50.

 

But if you were to word it a diifferent way, "If I flip the coin 10 times what are the odds of me flipping a tail?" they are substantially better than 50/50.

[toshiba]

..............

[CarnelianButterfly]

I have a minor is statistics, but have no care to argue this.

 

I prefer my current form of birth control, zero sex, that's 100% effective.

[melrich]

Yes, that's why you have a 2% chance of getting pregnant in 1 year. And you have a 2% chance of getting pregnant in your 20th year. But over the course of 20 years, it's much higher.

 

Yes the probability of getting pregnant by having regular sex over a 20 year period is higher than someone who has sex once.

 

But it is not,

 

So you have, let's say, a 2% chance of getting pregnant each year. That's a 10% chance of getting pregnant in 5 years. 40% chance of getting pregnant in 20 years. Not really that low...

 

The odds don't accumulate. Probability is a completely different set of mathematics.

 

And again, as I said before, even by the data you yourself referred to, if used properly, the failure rate on the pill is 0.1%...not 2%. That is 1 in a 1000, not 1 in 50.

[rocio]

I have a minor is statistics, but have no care to argue this.

 

I prefer my current form of birth control, zero sex, that's 100% effective.

 

I have a masters in econometrics but that in no way guarantees that I'm correct, especially since I spend my university years as a pothead and have completely forgotten at least 99% of everything I learned.

 

However, I still maintain that 96-99% is not such great odds. The IUD, on the other hand, is much more effective.

[CarnelianButterfly]

I have a masters in econometrics but that in no way guarantees that I'm correct, especially since I spend my university years as a pothead and have completely forgotten at least 99% of everything I learned.

 

However, I still maintain that 96-99% is not such great odds. The IUD, on the other hand, is much more effective.

Whatever, like I said, I'm not going to argue it.

 

Don't like it, don't do it. Easy peazea.

[rocio]

Whatever, like I said, I'm not going to argue it.

 

Don't like it, don't do it. Easy peazea.

 

No, you guys are right. My math is wrong. I'll blame it one the wine.

 

But, at the end of the day, the chances of getting pregnant while using the pill perfect for, say, 10 years, isn't really that low.

 

...which is why I get upset when people say things like, "if a girl says she accidentally got pregnant while on the pill, she must be lying..." ..because it can happen and it does happen.

[melrich]

But, at the end of the day, the chances of getting pregnant while using the pill perfect for, say, 10 years, isn't really that low.

 

...which is why I get upset when people say things like, "if a girl says she accidentally got pregnant while on the pill, she must be lying..." ..because it can happen and it does happen

 

Lots of people get pregnant using the pill but if you use it perfectly the chances are very low 0.1%. On the data you supplied it is about the best form of contraception there is. And what we are really trying to do is answer the OP's concern,

 

I'm just worried a bit... because since I never concieved once like 50% of the female population on the contraception does this mean that I'm not so fertile??

 

If you use it properly there is very very little chance of you getting pregnant, thereforeeee, the fact that she has not gotten pregnant in the last 4 years likely says nothing about her fertility.

[greenmonster]

Once again the media is doing its job of creating confusion and scaring people...

 

don't watch the news...you learn more from cartoons and game shows...the news is pretty much nothing more than a vomiting up of half truths and inaccuracies

[grendel]

If it is a 2% chance to get pregnant in a year, I believe it is close to a 40% chance in 20 years, though not exactly. It goes like this: you have a 98% chance of NOT getting pregnant each year and you multiply .98 times itself for the number of years you are concerned with, .98 to the power of 20 = 0.6676 = 66.8% chance of NOT getting pregnant in 20 years, = 33.2% chance of getting pregnant in 20 years. The reason it's not exactly 40% is because the same person may get pregnant in more than one year. That's how we did things in high school math anyhow. Also, as someone mentioned, you can't get pregnant while you are already pregnant which would affect the results in some small way that I'm not smart enough to figure out.

[greenmonster]

If it is a 2% chance to get pregnant in a year, I believe it is close to a 40% chance in 20 years, though not exactly. It goes like this: you have a 98% chance of NOT getting pregnant each year and you multiply .98 times itself for the number of years you are concerned with, .98 to the power of 20 = 0.6676 = 66.8% chance of NOT getting pregnant in 20 years, = 33.2% chance of getting pregnant in 20 years. The reason it's not exactly 40% is because the same person may get pregnant in more than one year. That's how we did things in high school math anyhow. Also, as someone mentioned, you can't get pregnant while you are already pregnant which would affect the results in some small way that I'm not smart enough to figure out.

 

eh...not exactly....

 

statistically speaking the probability of fliping a coin and it landing on heads or tails is 50%...and every time you flip it its a 50/50 chance on what side it lands...if you flip that coin 100 times in a row and it lands on heads, the 101'st flip is still a 50/50 chance

 

so you cant add up over 20 years of % points loss into one lump sum...because it would be a 98% chance every time...

 

the reality of the pill is with that 98% vs 2% is body chemestry of some people are different than others and can have an incredible impact on the effectivness of the pill.

[grendel]

The chance of never getting heads if you flip 20 times is .5 ^ 20 = 0.00000095,

the chance of never getting pregnant in 20 years if it's a straight 2% of pregnancy each year (which admittedly it isn't, due to aging, body chemistry, frequency of sex, whatever) is 0.98 ^ 20 = 0.6676... I'm not adding I'm multiplying.

[rocio]

So, I sat down and tried to remember my high school math:

 

The chances of getting pregnant at least once in 20 years is equal to:

 

-the chances of getting pregnant once, plus

-the chances of getting pregnant twice, plus

-the chances of getting pregnant 3 time.....

 

...and so on, up to 20 (well, if you could get pregnant every year, which you can't).

 

 

...or something to that effect. But my head hurts now.

_______________________________________________

 

Forgetting the math and approaching it logically.. On average, 2 women out of 100 will get pregnant in a year. So, assuming you could get pregnant while already pregnant, if you did the same test over again with the same women the next year, another 2 would get pregnant. Continue the test for 5 years, and 10 women should get pregnant, on average. After 20 years, there should be 40 pregnancies, on average.

 

But that doesn't necessarily mean that there's 40% chance of pregnancy after 20 years, because:

After 50 years, there would be 100 pregnancies, on average. 100 pregnancies out of 100 women. But that doesn't mean that a woman will get pregnant with a probability of 100% because the same woman could get pregnant several times.

 

So, the probabilities make my head hurt. But logically, after 20 years, there should be 40 pregnancies, on average. Shouldn't there?

 

______________________________________________

Sorry to anyone who felt I was being confrontational. I have no problem with admitting that I'm wrong, I'm more curious to know what the true answer is.

 

And, at the end of the day, it has little to do with the original point of this thread. So I also apologize if the OP feels I derailed the thread.

[RayKay]

Simply speaking, if you are using a 2% failure rate per annum, then yes...it is 40 pregnancies.

 

But you are still blurring your data. It is not 2% out of the same women over and over again and thereforeeee as they get pregnant it leaves less women overall and thereforeeee the odds increase. The 2% is a breakdown of a lot of data, out of MANY women. The 100 women is just representative of women on BC. It's not like they have 100 women sitting in a lab for 20 years and just use them for all their data.

 

In other words, it is 40 pregnancies out of 2,000 in that 20 years. Meaning the odds are still greatly in favour of not getting pregnant over getting pregnant (compared to the "no method" failure rate of 85%!). After 50 years it would be 100 pregnancies out of 5,000.