Will she get pregnant or not?
December 29, 2008 6:10 AM   Subscribe

Is it true that 3 days before and 3 days after a woman's period, there is sort of like a grace period, where the woman won't get pregnant?

Is it true that 3 days before and 3 days after a woman's period, there is sort of like a grace period, where the woman won't get pregnant?

My friend told me there but I need some articles and facts about it.

Please provide any reference if available

posted by minsid to Human Relations (21 answers total) 2 users marked this as a favorite
Um, no. Not true.
posted by lgandme0717 at 6:16 AM on December 29, 2008

That is definitely not true. For a quick overview, check out wikipedia on Human Fertility. For a much more in-depth and informative source, read Taking Charge of Your Fertility by Toni Weschler. A lot of the book is about how TO get pregnant, but it also talks about how not to, and it goes into very great detail about the timing of everything each month.
posted by vytae at 6:22 AM on December 29, 2008

Incidentally, a woman can also get pregnant during her period too. There is no grace period with any obvious outward signs at all.
posted by vytae at 6:23 AM on December 29, 2008 [3 favorites]

Your friend is likely referring to the relationship between menstrual cycles and infertility/fertility. The wikipedia article on the rhythm method and its references therein is as good a place as any to begin.
posted by vacapinta at 6:23 AM on December 29, 2008

You can still get pregnant.
posted by MaryDellamorte at 6:24 AM on December 29, 2008

Taking Charge of Your Fertility is a pretty good book that goes into detail on what to look for during a woman's cycle (of when she can and likely won't get pregnant).

You'll also need to consider that sperm can live for up to 72 hours in a woman's body (although these links say 6 days).
posted by pokeedog at 6:27 AM on December 29, 2008

No, read more about human reproduction. Since cycle length varies, you can get surprised by relying on calendar methods.

Do you want academic references? Any obstetrics text should do. If you're actually interested in research in this field, these are some examples. I recently heard this person give a talk on modeling this phenomenon. If you click her "more research" and "LIFE study" links you'll see more articles on this topic.

Short answer: day-specific probability of conception becomes low on some days, but not zero.
posted by a robot made out of meat at 6:29 AM on December 29, 2008

There is no certainty. You can only ever hope to reduce the possibility of becoming pregnant. Even with proper use of the Pill there is a 1 percent chance a year of pregnancy. With ordinary use that figure rises to just less than five percent. The same figures for condom are: 3% with correct use and 12% with ordinary use.

By using the calendar-method devised by Onigo and Knaus proper use will result in a 2 percent risk of pregnancy a year. A figure that rises to a whopping 30 percent if the method is not followed correctly.

Please note that the Onigo Knaus method is not in any way the same as the grace period you mention in your question.

I have not been able to find an accurate description of the method in english. But if you speak Danish you can find one here.

Good luck!
posted by FidelDonson at 6:35 AM on December 29, 2008

There is also lots of fertility information at CCL's Natural Family Planning website as well.
posted by jquinby at 6:39 AM on December 29, 2008

It is only a little bit half true. You are less likely to get pregnant right after your period, but still enough so that this should only be practised if pregnancy is n acceptable outcome.

I don't know if you or your friend are teens, but most sex ed type resources seem to be aimed at them. So, some pages with good info on reproduction that you can show to her are Scarlett Teen, and also the less chatty, more traditional education-style sexuality and u website run by the Society of Obstetricians and Gynaecologists of Canada. Both websites have lots more info, and the second one has an adult section, if that applies more.
posted by carmen at 6:40 AM on December 29, 2008

A woman is most likely to get pregnant by having sex a few days before, during, and a few days after ovulation. Especially in young women, whose cycle may not be well-established, ovulation may occur at an odd time during the cycle. Read up on the links in this thread, because it's good to be informed. If you don't want to have a baby, use condoms or another reliable form of birth control.
posted by theora55 at 7:13 AM on December 29, 2008

This little myth was proven NOT TRUE in 1969, with the birth of my first son.

Another myth that I proved NOT TRUE is the one about still being protected from pregnancy if you skip a pill or two. Son #2 born 1-20-76, after a bout of the flu which caused nausea and vomiting for ONLY ONE DAY!

Yeah. Life will win out over imprudent behavior almost every time.
posted by Corky at 7:36 AM on December 29, 2008

Use a condom. The rhythm method is a far from reliable form of birth contrl, if you can even call it that.
posted by chunking express at 7:37 AM on December 29, 2008

The only 100% way not to get knocked up is to not have sex. However if you must, use a condom. Do not go by hearsay or old wives tales. If you do then 9 months later you will end up a daddy. And if you are asking these types of questions I don't think you are ready for that.
posted by Mastercheddaar at 7:44 AM on December 29, 2008

It's not a "grace period" as such. It's more like an assumption that, on average, a woman is less likely to be ovulating during that time. This is because, on average, most women ovulate a couple weeks before their period.

But the real key word there is that "on average." Because when you get down to specifics, it's a complete and total crapshoot -- each individual woman's cycle is dictated by a shit-ton of different factors, any of which could have an affect on when she ovulates and when she menstruates. While it is true that most women do ovulate a couple weeks before their period, that won't help you if you happen to be with one of those exceptions to the rule who who ovulates three weeks before her period. Or one week before.

If you really want to try using fertility planning as a contraceptive method, there are many, many more things to check that are more accurate predictors for a specific woman's cycle than just checking the calendar.
posted by EmpressCallipygos at 8:28 AM on December 29, 2008 [1 favorite]

Generally true for some women, based on a whole range of factors that can't be gleaned from the calendar alone. Definitely not true for other women, and even sometimes for those women who are generally in the other category.

Use a condom.
posted by scody at 8:40 AM on December 29, 2008

(Or, in the event you're asking because the unprotected sex has already happened and you're hoping for some reassurance: presuming it's been less than 72 hours, there's always Plan B.)
posted by scody at 8:44 AM on December 29, 2008

Generally true for most women. But not always the case.
posted by roomthreeseventeen at 9:32 AM on December 29, 2008

I read somewhere that only 30% or so (paraphrasing from memory because I can't find the article again) of women have the typical cycle with ovulation on or close to day 14 after the period starts. That means 70% of women ovulate either sooner or later than that, some at one extreme possibly ovulating almost immediately at the end of a period. There's no way of knowing for sure where in your cycle you ovulate without testing over several cycles, and barring that, watching symptoms, temperature charting and other imperfect indicators used by women for natural family planning (and those methods take alot of time paying attention to your body to track accurately).
posted by slow graffiti at 11:57 AM on December 29, 2008

There's a name for people who practice the rhythm method: parents.
posted by angiep at 8:12 PM on December 29, 2008

Read the summary of this novel.

Natural family planning - Benefits: [...] can aid pregnancy achievement.

There are better contraceptive methods.
posted by ersatz at 4:46 PM on December 30, 2008

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