Posted 15 February 2014 - 07:37 AM
I could go pull the actual paper, but often for some things you need a very large cohort of women to get the background rate. If you only study women who took the drug and don't know the rate in other women (who did any number of other things) you don't really know if the drug did anything. Let me go see what I can find of all the other results other than the headline one.
And as they said, if you are vomiting to the point you cannot possibly provide adequate nutrition for the fetus, we know that causes problems with development.
ETA. So this is a cohort containing a huge number of pregnancies they can use for data mining.
They needed a huge number go get enough women with exposure to Zofran to get statistics. Each of the exposed pregnancies (woman who took the drug) was then matched with four unexposed pregancies from teh cohort (all women meeting the criteria in the national registry in a certain time period) so the unexposed women matched for a variety of things but were as similar as possible in this group to things like age, common diseases, weight, number of prescriptions during pregnancy.
So the comparison group was a subset of the larger cohort and to get the matched set you need a lot of people to sort through.
Would be nice to have a double blind placebo controlled study, but letting women vomit uncontrollably may not be ethical.
There doesn't seem to be a reason to think that in that data set they had anything other than the usual number of normal births and birth defects that you see in any other data pull. Do you have any other concerns about Danish women doing whatever is the standard medical practice there? Now I don't know the stats of the top of my head to know if they got more prescriptions or less than US women, but for all the various things pregnant women are exposed to, adding Zofran didn't seem to be a major risk, with the caveat you may not find the increases the risk from 1 in a million to 5 in a million in a group this size.
The biggest difference I saw is that the unexposed women who otherwise matched the exposed population had a higher rate of use of other anti-nausea drugs. Because like I said letting women vomit so much they may effect the fetus isn't good.
I know we all say no pregnant woman should ever take anything ever, most women are exposed to something during pregancy because just letting all the bad things that can happen if you do nothing to protect the health and well being of the mother. Development is a pretty delicate thing and it often goes wrong even when there is no particular exposure to something. There of plenty of reports of birth defects (obvious visible ones as well as babies just dying in the day or two after birth) in the ancient medical lit before the age of industrial chemicals and prescription drugs. Sometimes I find it a miracle any of us are born with the right number of parts given how many things have to go right during the pregnancy.