Fuzzy facts at the NIH?
Mar. 3rd, 2006 09:32 am![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
lederhosenVia Pharyngula, some shaky science at the NIH:
The NIH warns readers that "the 'morning after pill' is associated with a 10-fold increase in risk of [ectopic pregnancy] when its use fails to prevent pregnancy."
But Trussell et. al. write in the Journal of Family Planning and Reproductive Health Care:
We read with great interest the editorial about ectopic pregnancy (EP) following use of progestin-only emergency contraceptive pills (ECPs). The authors note that 12 EPs in women who used levonorgestrel ECPs have been reported in the UK and that a handful of additional cases have been reported in other countries. As the authors acknowledge, this information cannot be used to calculate the probability that a pregnancy occurring after use of the treatment will be ectopic because the total number of pregnancies needed for the denominator of the calculation is unknown. Nevertheless, based on these case reports, Britain’s Committee on Safety of Medicines (CSM) has advised that if a woman who has used progestin-only ECPs becomes pregnant, “the possibility of an ectopic pregnancy should be considered”.
Data from clinical trials of ECPs can yield an accurate estimate of the rate of EP because pregnancies in these trials are systematically documented and thus provide a valid denominator for the rate. Through a search of the published literature, we identified five clinical trials of levonorgestrel-only ECPs. As shown in Table 1, these trials reported a total of 97 intrauterine pregnancies and one EP. The proportion of pregnancies that were ectopic was thus 1.02% (95% exact CI 0.02%–5.55%). This proportion is consistent with the reported national rate of 12.4 and 19.7 per 1000 pregnancies in England and Wales and in the USA, respectively. Therefore, these trials provide no evidence to suggest that progestin-only ECPs increase the chance that a pregnancy will be ectopic. Moreover, because ECPs are so effective at preventing pregnancy in general, they certainly reduce a woman’s absolute risk of EP.
Further discussion here.
The NIH warns readers that "the 'morning after pill' is associated with a 10-fold increase in risk of [ectopic pregnancy] when its use fails to prevent pregnancy."
But Trussell et. al. write in the Journal of Family Planning and Reproductive Health Care:
We read with great interest the editorial about ectopic pregnancy (EP) following use of progestin-only emergency contraceptive pills (ECPs). The authors note that 12 EPs in women who used levonorgestrel ECPs have been reported in the UK and that a handful of additional cases have been reported in other countries. As the authors acknowledge, this information cannot be used to calculate the probability that a pregnancy occurring after use of the treatment will be ectopic because the total number of pregnancies needed for the denominator of the calculation is unknown. Nevertheless, based on these case reports, Britain’s Committee on Safety of Medicines (CSM) has advised that if a woman who has used progestin-only ECPs becomes pregnant, “the possibility of an ectopic pregnancy should be considered”.
Data from clinical trials of ECPs can yield an accurate estimate of the rate of EP because pregnancies in these trials are systematically documented and thus provide a valid denominator for the rate. Through a search of the published literature, we identified five clinical trials of levonorgestrel-only ECPs. As shown in Table 1, these trials reported a total of 97 intrauterine pregnancies and one EP. The proportion of pregnancies that were ectopic was thus 1.02% (95% exact CI 0.02%–5.55%). This proportion is consistent with the reported national rate of 12.4 and 19.7 per 1000 pregnancies in England and Wales and in the USA, respectively. Therefore, these trials provide no evidence to suggest that progestin-only ECPs increase the chance that a pregnancy will be ectopic. Moreover, because ECPs are so effective at preventing pregnancy in general, they certainly reduce a woman’s absolute risk of EP.
Further discussion here.
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no subject
Date: 2006-03-02 10:55 pm (UTC)Why can't anyone do the bloody math?
Gah.
no subject
Date: 2006-03-02 10:58 pm (UTC)no subject
Date: 2006-03-02 11:44 pm (UTC)One of the very last activist battles I was (very peripherally) involved with before my manditory term-limited retirement from the activist service (at least, until I finally graduate and become a resident) was an effort by the American Medical Association to fight back against a series of actions where the Bush Administration very quietly made certain bits of information... disappear from various websites, mostly related to contraception and/or abortion. The one that got the most press was actually an effort led by my good friend Albert (of which I've written before) to oppose the FDA pretty much bloody ignoring the scientific evidence on ECPs and blockading access.
Yeah, to say the least, the current administration is not precisely particularly popular in medical or scientific activist circles...
no subject
Date: 2006-03-03 05:31 am (UTC)//: *headdesk* ://
Well, yes. As always. And only if there's abdominal pain.