What are the chances of Pregancy during unprotected sex?

[99problems]

Forgive my ignorance on this area, simple question really...

[dirtyharriet]

I'm no statistician but it would depend on whether your partner ejaculated inside you and what stage of your menstrual cycle you were on.
Most women ovulate around 14 days before their next period.

[andy hughes]

I always instilled into my children that, what ever the pleasures of sex - it is a procreational act, and as such, nature has weighed the oddds in favour of success to a considerable degree. Look at it this way - if every sperm in the average ejaculate fertilsed one egg, the resulting stattistical birth rate would be enough to repopulate North America - that's the continent. So, on the basis that only one sperm has to succeed, you can work out the chances of prgnancy. Simply put, what do they call people who have unprotected sex? Parents.

[Scarlett]

Also many people can try to get pregnant for years with no success. Other people get pregnant on the first go. It depends on so many things- health, age, cycle... I don't think I have ever read a statistic about the probability of getting pregnant, as so much depends on other factors that you just cannot know until you try.

[Octavius]

It only takes one little swimmer to do the job.

 

The chances of a woman becoming pregnant depends on both her and her partner's level of fertility, as well as what time of the month they are engaging in intercourse. These factors are much more important than how many times each week a couple has intercourse. An active sex life only increases the likelihood of a pregnancy when it occurs during the time of the month when the woman is fertile.

 

If you really want to swing the odds of getting pregnant in your favor, you're better off timing sex as close to ovulation as you can. For most women that's about halfway between periods.  And while it's important to be familiar with your cycle, it's equally important to try to relax and enjoy sex. The more relaxed you are, the better your chances of conceiving. So have sex whenever the mood strikes you � day or night!

[moonface]

a million to one, but studies show million to one chances happen 9 times out of 10

[Westminster]

No one seems to have answered the question. The chance of conceiving at a single instance of unprotected sex, happening at a random moment in the menstrual cycle, is fairly low. Assuming that the partners are young, fertile, and healthy, then repeated instances of unprotected sex distributed throughout the menstrual cycle will greatly increase the probability of pregnancy.

[spainlads]

Also, what's the chances of getting HIV????

[Octavius]

Spainlads - your answer is here:

http://answers.google.com/answers/threadview?id=73514

 

Westminster - you have just repeated all the other answers

[Marsh]

From:-
 http://www.bbc.co.uk/health/ask_doctor/pregnant_tryingto get.shtml
"The average chance to conceive for a normally fertile couple having regular unprotected intercourse is around 25% during each menstrual cycle. This is based on the couple having sex at least every couple of days"

If you are talking about one occasion only;-
If 25% is happening with 15 times per cycle, simple maths suggests one chance in sixty.  However, this should be an over-estimate because the couple will be covering the woman's fertile period every month.  You may have missed yours entirely.  There's a 5-6 day time slot each cycle outside which nothing will happen ( http://www.fwhc.org/birth-control/fam.htm ) .  This could bring the odds down to one in three hundred.
This figure has been worked out with a calculator from information on two web-sites.  I have no formal training on the subject.  The odds should be between those two extremes, I would have thought.

[Marsh]

Further thoughts:
My calculations didn't allow for abstinence during periods
A baby is for life, not just Xmas
If you do get HIV, they can't cure it.
Carry a condom always: make it an entry ticket.