[whoisjuan]

Data dredging is usually establishing a causation or pattern of two loosely correlated variables with no clear undesrstanding of why one have effects on the other. (correlation != causation).

In this particular case they seem to have a clear hypothesis on why there could be a strong link between one and the other: > "Oral sex might induce maternal tolerance towards paternal antigens of the fetus".

Anyway. This doesn't mean that this is a strong study. Just pointing out that at least they seem to have a theory on why oral sex can protect against miscarriages.

[aristophenes]

We don't know how many different things did they ask for on the survey? Maybe they had 100 different things that they were just spitballing might have some possible effect.