Is 20% a myth?

adunkin · February 2013

So, we always quote this stat. And I wondered where it comes from. And I love science and research. So, I went digging.

In my preliminary research, the only thing everyone seemed to agree on was that female fertility decreases by at least 3.5% every year after 30.

The Southern California Center for Reproductive Medicine says:

- The pregnancy rate per month of a woman in her 20?s is about 20-25%. Because of this, a woman should seek help with fertility if she has been unsuccessful trying to conceive after 12 months of actively trying.
- Women in their thirties will experience a decline in their fertility such that the fertility rate per month is about 15%. Women should seek medical help after 9 months of actively trying to become pregnant.
- There is a noticeable decline in the fertility rate starting at age 35 to a level of about 10% per month. A woman seeking pregnancy over 35 should consult a fertility specialist after only 6 months of actively attempting to become pregnant.

Yes, it is a fertility center so perhaps they have an interest in getting women to come in earlier and start trying sooner. But this isn't the first time I've seen these numbers. This is just one of the more reputable places I've seen them published.

Researchers from the University of Warwick and the London School of Economics recently published a study saying they can calculate the chances of getting pregnant. (A graph of their stats below.) They have submitted their findings to the UK's NIH in hopes of influencing changes to care guidelines.

I find this graph shocking (and horrifying - personally). But these make me wonder if our 20% until age 35 is an outdated stat and/or where we even got the idea that everything is equal up until 35 years of maternal age.

adunkin · February 2013

CLECyclist:
I wouldn't have a conniption. You're citing one study/resource. Who does it reference? Are all the women in the study healthy? No PCOS, luteal phase defects? Nothing? If the study is all inclusive it will bring the numbers down. The answer to this question depends on who you ask, who the sample base is, what the data set/sample size is...

Haha - no conniption had. It's something I've often wondered about. So, I did some initial research and thought I'd put it out there for thoughts. London School of Economics is pretty reputable though so I'd bet their study methods are solid. (btw - I love the word conniption. People should use it more often!)

lrosy13 · February 2013

Very interesting.

MrsM507 · February 2013

It's interesting, but lacking way too much info to get overly freaked out about it. Like CLE said, it's just one study.

MarieC78 · February 2013

We are on our 4th cycle trying, and I'll be turning 35 during out 5th. It seems entirely to soon for us to explore fertility testing in April...yet everything seems to indicate I should.

ETA: This was basically just a statement, but I suppose the question behind that would be any opinions? It just feels too soon for all that.

adunkin · February 2013

MrsM507:
It's interesting, but lacking way too much info to get overly freaked out about it. Like CLE said, it's just one study.

I totally agree about not getting freaked out. But there are two different sources listed above. What do you think about the 9 month recommendation for women 30-34 yrs?

tbird_1211 · February 2013

This made me have an "Oh, CRAP!" moment, but then I realized that any study can be faulty. I'm sticking with my 10%-15% chances per month!

MarieC78 · February 2013

I think that means I'd be going to the doctor next month. It seems too early for that. Even after reading this, I'm still comfortable waiting until the 12 month mark to see a doctor.

I feel the same way, but considering I've never been pregnant, I'd hate to wait and find out I should have gone earlier. I'm just gonna boycott getting older. That'll fix it. Confused

MrsM507 · February 2013

adunkin:
MrsM507:
It's interesting, but lacking way too much info to get overly freaked out about it. Like CLE said, it's just one study.
I totally agree about not getting freaked out. But there are two different sources listed above. What do you think about the 9 month recommendation for women 30-34 yrs?

I have seen a lot of women in their early 30's end up pregnant within 6-12 months of trying... I think 9 months is too early.

ETA unless there is a pre-existing condition or a reason to suspect a problem.

vpine · February 2013

My Dr actually told me same as your graph (I'm 30). Not sure if it's accurate or not.

ayamw · February 2013

In theory I think the "sliding scale" makes sense RE: 30-34 yr olds - 9 months. It's not like you turn 35 and your fertility drastically plummets so I could see that making sense. Interesting - thanks for sharing.

adunkin · February 2013

CLECyclist:
adunkin:
Haha - no conniption had.
You said your were horrified. I'd say that's a conniption!

Ah - well, according to it I've actually got something like a 7% chance of getting pregnant next month, which isn't nice to think about. But more importantly - did you look at that graph?! It's so ugly! I mean - honestly, for some reason the font and colors in this graph make my eyes and my ppt loving soul hurt! Crying

adunkin · February 2013

ayamw:
In theory I think the "sliding scale" makes sense RE: 30-34 yr olds - 9 months. It's not like you turn 35 and your fertility drastically plummets so I could see that making sense. Interesting - thanks for sharing.

Yeah, I think I agree with you. A sliding scale theory does make more sense to me, especially considering it is while accepted that fertility peaks in your 20s.

FutureMrsCaesar · February 2013

I've seen a lot of what you are saying out there recently as well. I just turned 30 so it's like suddenly all this 'declining fertility' now applies to me and I've been doing more research. Most of what I've been seeing lately is the 30-34 15% chance each month, which like you said, makes sense, it's not like suddenly at 35 it drops immediately. However, I think the graph does seem rather grim, and I guess I'd like to see some of the data behind it. Like others have said we don't know the parameters of the study, were the people healthy, overweight, smokers, pre-existing conditions, etc.

ChicagoWeded2007 · February 2013

Here's an interesting article about chances of getting pregnant. It reflects an increased chance of pregnancy with timed sex. https://www.babycenter.com/0_how-long-it-takes-to-get-pregnant_1813.bc?page=1

"Of all couples trying to conceive, here's about how long it takes:

30 percent get pregnant the first cycle (about one month)
59 percent get pregnant within three cycles (about three months)
80 percent get pregnant within six cycles (about six months)
85 percent get pregnant within 12 cycles (about one year)
91 percent get pregnant within 36 cycles (about three years)
93 to 95 percent get pregnant within 48 cycles (about four years)

In one study, the pregnancy rates of couples who timed intercourse with ovulation were faster than typically seen among couples trying to conceive:

38 percent were pregnant after one cycle
68 percent were pregnant after three cycles
81 percent were pregnant after six cycles
92 percent were pregnant after 12 cycles"

adunkin · February 2013

ChicagoWeded2007:
Here's an interesting article about chances of getting pregnant. It reflects an increased chance of pregnancy with timed sex. https://www.babycenter.com/0_how-long-it-takes-to-get-pregnant_1813.bc?page=1
"Of all couples trying to conceive, here's about how long it takes:
30 percent get pregnant the first cycle (about one month)
59 percent get pregnant within three cycles (about three months)
80 percent get pregnant within six cycles (about six months)
85 percent get pregnant within 12 cycles (about one year)
91 percent get pregnant within 36 cycles (about three years)
93 to 95 percent get pregnant within 48 cycles (about four years)
In one study, the pregnancy rates of couples who timed intercourse with ovulation were faster than typically seen among couples trying to conceive:
38 percent were pregnant after one cycle
68 percent were pregnant after three cycles
81 percent were pregnant after six cycles
92 percent were pregnant after 12 cycles"

Nice work. I love that you posted with studies. I think it's easy to agree with the second part - couples who time sex accordingly get pregnant faster than those who don't.

The first part I find interesting. It's definitely not the first time I've seen statistics like this. (At first I found them hopeful. Now they sort of point out my inability to stay within the "norm". ::shrug:: ) But it does make me wonder if they are lumping women of all ages together and if it's just based on women in the US or elsewhere.

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