The chances are very low especially considering you didn't go all the way, why? Read on... (tame version, all you adults use your imagination)
During normal intercourse (for the point of conceiving) billions of sperm cells are delivered into the female subject. Now, the fluids which sustain your DNA are basic in nature, however inside the female the environment is very acidic, which is a natural defense mechanism to stop microflora and microbes from colonising that area. This means almost a third of your sperm cells are dead before they manage to enter the uterus. Now, from there onwards, they need to make a very long journey (a day or two) into the Fallopian tubes to rendezvous with the ova. Remember they have a very limited sugar supply to keep them going; they're swimming in the dark; millions of lymphocytes (your body's defense cells) attack them along the way and a huge proportion of your sperm is initially mutated (eg. having more than one tail, or no genetic material etc.).
Now, let's say your sperm does rendezvous with the egg and it begins to divide, a large proportion of embryos miscarriage because there is something wrong in the cell division or some part of the embryo has not developed.
And these are the odds if you are trying to conceive.
Now, you said you didn't go all the way, which means your chances are even worse for conceiving. And one more thing, just because a girl has a delayed period, or even missed a period for that matter, doesn't mean she is pregnant, many environmental factors can cause it, for example food, nutrition, stress etc.
So yeah, if you're really worried, get a pregnancy test done (wait awhile, see if she misses a period).
During normal intercourse (for the point of conceiving) billions of sperm cells are delivered into the female subject. Now, the fluids which sustain your DNA are basic in nature, however inside the female the environment is very acidic, which is a natural defense mechanism to stop microflora and microbes from colonising that area. This means almost a third of your sperm cells are dead before they manage to enter the uterus. Now, from there onwards, they need to make a very long journey (a day or two) into the Fallopian tubes to rendezvous with the ova. Remember they have a very limited sugar supply to keep them going; they're swimming in the dark; millions of lymphocytes (your body's defense cells) attack them along the way and a huge proportion of your sperm is initially mutated (eg. having more than one tail, or no genetic material etc.).
Now, let's say your sperm does rendezvous with the egg and it begins to divide, a large proportion of embryos miscarriage because there is something wrong in the cell division or some part of the embryo has not developed.
And these are the odds if you are trying to conceive.
Now, you said you didn't go all the way, which means your chances are even worse for conceiving. And one more thing, just because a girl has a delayed period, or even missed a period for that matter, doesn't mean she is pregnant, many environmental factors can cause it, for example food, nutrition, stress etc.
So yeah, if you're really worried, get a pregnancy test done (wait awhile, see if she misses a period).
