It may seem silly to address a topic that many of us had explained when we were very young. Unfortunately, very few of us had it explained well, leaving a good many with no idea what the birds and the bees really mean to our everyday sexual lives.
Every day someone at Scarleteen asks if this, that or the other thing is a pregnancy risk, or how they can tell if they are pregnant, or how they can even get pregnant in the first place. It isn't stupid or immature not to know the answers to these questions. It is only foolish not to ask them when we don't know the answers, or to assume we'll just be "lucky," and so never try to learn. At least 40% of all women get pregnant before they turn 20 years old, and approximately 70% of those pregnancies are accidental. Among people of all ages who do become pregnant, as many as 50% of all pregnancies are unplanned. Clearly, it is something to be concerned with, something many people DON'T understand, and something most people aren't so lucky with after all.
You probably already know that for someone to get pregnant, sperm has to reach an egg and fertilize it. You may also know that happens almost exclusively through genital intercourse. Those are basics that are great when you're six, but are a bit too ambiguous when you're actually capable of becoming pregnant or taking part in creating a pregnancy. So, let's take a new look at the whole thing, from a realistic standpoint.
The script for human reproduction involves two main characters: sperm and ovum, but also a good supporting cast of body fluids, our reproductive organs and some cameo roles.
Let's start with one common misunderstanding. Semen and sperm are not the same thing, though many people often think so, and refer to them as the same. Semen is, in fact, a combination of fluids -- called seminal plasma -- from the prostate gland, cowpers gland and the seminal vesicle, and sperm. Semen contains sperm, but it is not sperm. Less than 5% of semen is sperm.
Semen and vaginal fluids -- cervical mucus -- are the strong supporting cast to our leading actors: without them, the sperm and ovum couldn't accomplish much when it comes to reproduction.
Of Sperm and Semen: A person with a penis and testicles usually produces millions of sperm each and every day, and they are microscopically small. Just one drop of semen has more than one hundred million sperm in it. No kidding. When ejaculation occurs, ejaculate normally has between 200 and 600 million sperm in it. Semen isn't irrelevant: it's needed both to balance out the acidic nature of the vaginal environment to keep sperm viable, and is also needed to help sperm move to the cervix.
Because the sperm are super-sensitive to the environment outside the testes (or "balls"), only about 50 of sperm in an ejaculation will be able to reach an egg. That is why the body produces so many, because most of them die en route. But while only one sperm actually fertilize the egg (save in a rare type of twin), a couple hundred "helper" sperm play wingman to help that one get in.
Of Ova And Cervical Mucus: In most people of reproductive age who have a vagina and uterus, one mature ovum or egg is released each fertility cycle (which is anywhere from three to five weeks long for most individuals) from the ovaries into one of the fallopian tubes. Usually, only one tube at a time has a fertile egg in it, though that is not always the case, as some people may release more than one ovum each month. After sperm pass through the vaginal canal and the cervix, some of them will go to one fallopian tube, and some the other, seeking out that egg. Cervical mucus and vaginal fluids must contribute to this: without the right consistency of those fluids, sperm can't swim upstream very well. At the most fertile time of the cycle, an egg is being released and cervical fluids have a thin, stretchy and fluid consistency.
Those that went to the tube with a live egg surround it and try to enter the sac. Sperm can live in the vagina for several days, so given the timing, that may or may not happen on the same day sperm came to the door.
If the ovum is healthy and viable, sperm will penetrate it and fertilize the egg. The ovum only allow one sperm to fertilize the egg, and if that happens, no other sperm are allowed in. It's a bit like calling into a radio station for a contest: once the 50th caller gets on the line, they stop answering the phone.
If the process continues another step, about a day or so after that happens -- and the egg, fertilized, becomes a zygote -- the egg starts to divide into many cells, staying in the fallopian tubes keeping busy with that for a few days. That zygote then usually starts moving towards the uterus, dividing more all the while, with the intent of attaching to the endometrium. Before it does that, it changes some more, and can then become a hollow ball of cells called a blastocyst, and that is what may -- or may not -- implant in the uterine wall and then become an embryo and a bonafide pregnancy.
Many times, without any interference from anyone, fertilized eggs just don't implant and a pregnancy does not occur. But when pregnancy happens, from the moment that ejaculate enters the vagina to an actual pregnancy it can take anywhere from around five or so days (which is why emergency contraception can work for up to 120 hours after a risk) to well over a week to complete.
On potentially any day there is vaginal contact with sperm, and most typically through vaginal intercourse. There are times in a fertility cycle (like a few days before and the day of ovulation, when the mucus of the vagina is most friendly towards sperm) when a person is MOST likely to become pregnant, and times when a person is least likely and even not at all likely to become pregnant, but someone can technically get pregnant because of live semen in the cervix at nearly any time. As fertility cycles differ a lot from person to person, there is no one safe or one fertile time for everyone.
Trying to predict times of ovulation is usually something that is done when you are TRYING to get pregnant, not trying to avoid it. However, some people chart their fertility cycles to be informed about their own bodies, some use that charting as a method of birth control (though using it solely isn't advised for younger people, or for couples who really can't deal with a pregnancy), and some use charting in conjunction with another method of birth control, such as condoms, by using condoms for all intercourse during all of the cycle, save the most fertile period, during which they abstain from genital intercourse completely. To chart fertile cycles and predict when you (or your partner) is most and least likely to be fertile, a person will need to have had regular menstrual cycles for at least a few years, then every day look at cervical mucus (with a finger or a speculum) and take a basal body temperature, with the help of a teacher or good guide to know what's what. After doing that for a few months, so long as cycles are regular, one can predict with a good deal of accuracy when ovulation and highest fertility is likely to occur in the upcoming cycle, and know when it happened in the previous ones.
But counting days per periods based on average fertile times for all people is not a very sound way to do that as it is not likely to be very accurate, since we don't all have the same cycle.
You can get pregnant at any time after around two weeks before your first menses (or period). Whether or not your corona (hymen) is intact is a nonissue, since it may well be broken (or more accurately, stretched or worn away) long before someone first has intercourse. In any case, even if intercourse or sexual contact doesn't fully stretch your hymen, which it usually won't, nearly all hymens have small holes -- called microperforations -- in them for menstrual flow that will allow sperm through as well.
If semen comes in direct contact with a vagina, pregnancy can occur. It really is that simple.
Overall, the MOST likely way to become pregnant is by direct vulval or vaginal contact with sperm. Sperm can live up to about 20 minutes in an environment that is unfriendly to them (in other words, outside the testicles, vagina or in lab conditions), but they are very delicate creatures in the great outdoors. Superheoes they are not. So while, for instance, having unprotected anal sex where sperm can run right down into the vagina does create a possible risk of pregnancy, it isn't as likely a risk as it is with vaginal intercourse. If there is a distinct barrier between the vagina and the penis in question, such as clothing, water or an interstate highway, there is not a likely risk of pregnancy.
In addition, you cannot get pregnant by swallowing semen, by oral sex, or by manual (with hands, or "fingering") sex. You CAN, however, catch or transmit STIs that way.
As far as birth control methods, read our birth control guide to see which ones are the most effective, but overall, the MOST effective method of birth control (and the best when it comes to also reducing the spread of STIs) is a condom plus an additional birth control method. Many teens who are not yet ready for intercourse or sexual activity where a condom is required don't keep them -- or other birth control -- handy. However, many unplanned pregnancies have occurred when people express things "just happened" or when one partner caves into pressure from another to have sex, even though they weren't planning on it. Do yourself a favor: just like you'd always keep a spare tire on your car in case of an emergency flat, keep a condom or two around with some lubricant, just in case you need them. There is absolutely no harm in being prepared.
MOST accidental pregnancies occur within the first six months of intercourse. A sexually active teenager who does not use contraceptives has a 80% chance of becoming pregnant within one year, a far better chance than anyone has of winning the lottery (would that we had that big a chance of winning the lottery!). In addition, your chances of contracting or transmitting a sexually transmitted disease or infection are also even greater than the chance of getting pregnant. Every year about one in four sexually active teens acquire an STI. One in four. That's why we think you should be concerned about them both.
According to Unintended Pregnancy Among U.S. Adolescents: Accounting for Sexual Activity, by Lawrence B. Finer, director of domestic research at the Guttmacher Institute, the unintended pregnancy rate among teens who are sexually active (147 per 1,000) is more than twice the national figure for all sexually active women of reproductive age (69 per 1,000). The rate among sexually active 18–19-year-olds (162 per 1,000) is more than double the national figure. There are substantially greater numbers of unintended pregnancies still among women aged 20–24 than among younger women.
By taking a pregnancy test.
There is no other way to know for sure early enough in the game to adequately consider your options. Most early symptoms of pregnancy do not show up until at least a couple weeks after conception, sometimes longer than that. Too, when early pregnancy does have symptoms, they're usually the same kinds of symptoms as PMS. You can use a home pregnancy test either after your first missed period, or around two weeks after your risk, and should repeat the test one week later if you get a negative result. The most reliable test is done by a doctor or clinician. If your test shows a positive, you should then go to a doctor's office or family planning clinic (like Planned Parenthood) and have a test done there. Home pregnancy tests are generally very reliable anymore, but positives should be verified professionally.
If you've been having intercourse and miss a period, then you'll want to take a test. Again, pregnancy is far less likely when a reliable birth control method has been used, and nearly impossible if you've also used a backup method, but we don't yet have a method which is 100% reliable, and it's always better to find out as early as you can if you are pregnant.
If an accidental pregnancy does happen, then you'll have to make one of two choices: you can choose to remain pregnant, and then deliver and either parent or take part in adoption, or you can choose to end the pregnancy with an abortion. All three of those choices are valid and usually available to people of all ages. Abortion is usually where there may be restrictions, because a pregnancy has gone too far to terminate, because abortion is not legal in your area or nation, or because your age presents limitations in terms of your rights to access abortion in your area.
Many people have experienced feeling good about all of those choices; many people have expressed feeling bad about all of those choices. What's right for each person or each pregnancy is very individual. When someone tends to feel best isn't about one of those choices being the one most or all people feel best about: there isn't any one that's most often best. Rather, people have had good experiences with all those choices, and that's often most strongly influenced by someone having been able to freely choose what they really wanted, and be fully -- interpersonally, economically, culturally and via a high standard of care -- supported in that choice.
While we all obviously want to do all you possibly can to prevent a pregnancy you don't want or know would not be sound, a pregnancy doesn't mean it has to be the worst thing that ever happened to you. Any of these choices can be good choices with good outcomes, even if making them is difficult, which it often is.
Obviously, it is greatly helpful to hold off on intercourse until you are really ready to handle the risks, including an unplanned pregnancy. Educate yourself about sexuality and your body and find out the risks you're taking before you take them. If you cannot obtain, afford or stick to a reliable birth control method every single time there's vaginal contact with a penis, and don't want to become pregnant, you'll need to avoid sexual intercourse. It's that simple, and that doesn't need to be torture. Anyone who tells you that it is is kidding you, and is kidding themselves. Sex is about many things, only one of which is intercourse (and it isn't that different from other forms of sex, like oral sex), and the sex that is best for everyone -- on all levels -- is always only the sex that you want and feel really ready for, even when that is no sex at all.
And in case it wasn't clear before you read this piece, intercourse's primary objective is creating a pregnancy, even if that isn't your objective in having it. So if this whole process up there isn't something you want happening in your own or a partner's body, either contraception or no babymaking-sex at all are the ways to skip a trip down the sperm superhighway.