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Comment by genter | Hacker News Reader

99% effective. So if you have sex once a day, you'll only produce 3 kids a year.

Birth control effectiveness is typically reported for one year of use, so 100 years of use would produce 1 pregnancy on average

Or, one year of use by 100 men would result in an average of one partner pregnancy per year for this group.

So a kid a year? A couple married at 18 would be on the road to a record family size at 1 kid a year

No, a kid per hundred years.

oh well that makes much more sense. Thanks for clarifying

That's not how birth control effectiveness is measured. It's not measured per act of intercourse.

Birth control effectiveness is measured by calculating the number of pregnancies per 100 women using a specific method for a full calendar year.

https://www.who.int/news-room/fact-sheets/detail/family-plan...

>Effectiveness of methods is measured by the number of pregnancies per 100 women using the method per year.

Is that adjusted for frequency of intercourse? Can’t really compare a woman who has sex 10 times a year to one who’s having sex 20 times a month.

I assume the "per 100 women" part suffices to regress towards the mean

How is it measured in mice and non-human primates?

As someone who's currently producing 365.25 kids a year, I'll take it.

> In male mice, the drug caused infertility and was 99% effective in preventing pregnancies within four weeks of use.

I don't know if they mean 99% reduction compared to normal or 99% of mice did not cause a pregnancy. Either way this does not mean that every intercourse has a 1% chance of causing a pregnancy. Also you are assuming an unconditional probability. It could very well be a conditional probability. It might completely work for 99% that do not cause any pregnancies at all and not work for 1% that cause pregnancies as without the drug.

Anyway I am looking forward to getting the perl index for humans from clinical trials.

Edit: fixed wrong wording

Female birth control states the same, as nothing is ever 100%

Sometimes life, uhh, finds a way.

But yes, if they said something is 100% effective and it wasn’t, I would imagine they would be sued into bankruptcy pretty fast.

How much would an accidental child cost these days?

With the female contraceptive pill 0.3% of women get pregnant within a year if taken perfectly (which is rarely the case, but the figure here is also from lab conditions). This drug leads to 1% pregnancies in 4 weaks, which is much worse.

That said this is still great news especially as the condom is also much less safe then the female contraceptive pill.

Condoms are extremely effective also, if used perfectly, which is rarely the case. Statistics should be based on real-world experience not theoretical best case.

Wikipedia gives a 2% pregnancy rate for condoms within one year with perfect use which is much worse than 0.3%.

We only have the numbers for the lab environment with I assume perfect use for this new drug, so we can only compare perfect use.

I've always been intrigued by where those 2% come from, since condoms are a physical barrier... Teleporting sperm?

The statistics show that the 2% comes from breakage/slippage, micropores and manufacturing defects:

https://www.contraceptionjournal.org/article/S0010-7824(04)0...

Mostly misuse. The studies are all nonsense AFAIK, they rely on the participants to use the condoms correctly, which predictably doesn't happen. Problems the studies mention, like slippage and breakage are the result of misuse, probably due to choosing the wrong condom size.

The only reason for a properly used condom to not work would be a manufacturing defect, which should be extremely rare, certainly not 2%, that's plainly ridiculous and immediately disqualifies any study that claims so.

It's worth measuring both ideal and real world use, IMO.

The statistics are based on real world experience rather than theoretical best case. Not to pick on you but really surprised to hear people confidently express so much misinformation on this topic when it's not even particularly hard to find information on it:

https://en.wikipedia.org/wiki/Comparison_of_birth_control_me...

What throws me off about this, is it's not difficult to use perfectly. Condoms are the only method I trust. Pull-out? Can screw it up. With birth control you're (until now) relying on your partner to use it perfectly.

you really have to take that pill as soon as it enters the market (/s)

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