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This article has the following claims about success rates of couples trying to conceive.

One study, published in the journal Human Reproduction, followed women who were trying to get pregnant by having sex at the time in their monthly cycle when they were believed to be most fertile. Of the 346 women in the study, 310 conceived in the first year. The breakdown was like this:

38 percent were pregnant after 1 month.

68 percent were pregnant after 3 months.

81 percent were pregnant after 6 months.

92 percent were pregnant after 12 months.

I'm skeptical of these claims, as my previous research into odds of conceiving suggest an optimistic best case of a 20% chance per month and generally closer to a 15-18% chance even doing everything right. The numbers claimed by the article appear significantly higher then this.

Are the quoted numbers representative of odds of conception for women trying to conceive?

Community
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dsollen
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    Here is the paper in question: "Time to pregnancy: results of the German prospective study and impact on the management of infertility"; C. Gnoth, D. Godehardt, E. Godehardt, P. Frank‐Herrmann, G. Freundl. *Human Reproduction*, Volume 18, Issue 9, 1 September 2003, Pages 1959–1966, https://doi.org/10.1093/humrep/deg366. It's open access. – Nate Eldredge Aug 08 '17 at 23:51
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    Please note that this is an article published in an apparently reputable peer-reviewed medical journal; on this site we tend to consider such evidence as the "gold standard" and don't assume that we have the subject-matter expertise to critically analyze their methods. That's not to say that we automatically *believe* such claims, but that they need more specialized examination than we can provide. – Nate Eldredge Aug 08 '17 at 23:54
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    On the other hand, we can try to evaluate whether the results claimed by the paper are accurately described by the summary in the popular article. – Nate Eldredge Aug 09 '17 at 00:03
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    It might help if you could give references for your previous research as well. We could compare them to find differences in their methods that might explain the different results. – Arsak Aug 09 '17 at 06:54
  • Maybe the question can be answered by finding other studies to see if they agree with this one. The title seems to ask whether the 38% is correct in general, but the body seems to ask only about this particular study. – GEdgar Aug 09 '17 at 13:43
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    Where someone expresses skepticism about a peer-reviewed article, it raises the bar for an answer (we need to provide evidence of a higher quality) and makes the question more likely to remain unanswered, but it's still on-topic. – Oddthinking Aug 09 '17 at 14:19
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    @Marzipanherz: I did a short search on this one. I found a study looking at the mother's weight and finding a relationship there, so it wouldn't surprise me to see different results based on different countries/cultures studied (e.g. Germany versus USA) – Oddthinking Aug 09 '17 at 14:22

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That study was published in Germany in 2003. As Nate Eldridge says, the reference is "Time to pregnancy: results of the German prospective study and impact on the management of infertility"; C. Gnoth, D. Godehardt, E. Godehardt, P. Frank‐Herrmann, G. Freundl. Human Reproduction, Volume 18, Issue 9, 1 September 2003, Pages 1959–1966, doi.org/10.1093/humrep/deg366.

Another study published in 2003 with data from China was: Wang X, Chen C, Wang L, Chen D, Guang W, et al. (2003) "Conception, early pregnancy loss, and time to clinical pregnancy: a population-based prospective study." Fertil Steril 79: 577–584. doi.org/10.1016/S0015-0282(02)04694-0

The Chinese study does not seem to be open access but states in its abstract

The conception rate per cycle was 40% over the first 12 months. Of the 618 detectable conceptions, 49 (7.9%) ended in clinical spontaneous abortion, and 152 (24.6%) in EPL [Early Pregnancy Losses]

If you take account of the losses, then this gives fewer pregnancies after one month in the Chinese study than in the German study but more pregnancies after more months. A modelling paper (see the tables for examples 1 and 3) seems to confirm this. But between them, they are not substantially different, and they are both much higher than your previous opinions

Henry
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