Precum is the fluid that is released from the penis during intercourse prior to ejaculation, and it can have a high concentration of sperm. If precum enters your vagina, the sperm can move up into the uterus and fertilize the egg.
You can easily get pregnant from precum.
Several published reports show consistently that pre-ejaculatory fluid or precum does contain enough sperm to get a woman pregnant. In a study by Killick et al in 2011, about 40% of precum had enough mobile sperm for impregnantion. Therefore, because precum contains a lot of sperm, the commonly known withdrawal method or "coitus interruptus" is a bad contraception method and can lead to pregnancy.
Precum derives from the Cowper's gland and is a fluid that often comes out of the penis during intercourse, shortly before he fully ejaculates. Most men don't even notice discharging precum when it happens, but there are many sperms inside the precum.
If you do not want to get pregnant, then you must always use effective contraception.
According to recent studies from Kovavisarach and another from Killick consistently show sperm in precum and the capability for fertilization. Precum often contains many mobile spermatozoa (sperm cells, delivering the nucleus with the genetic information of the male to the ovum of the female) which is often enough for fertilization and pregnancy. Presumably, the pre-cum works like a lubricant and acid neutralizer but it does contain sperms. Both the concentration of sperm in pre-cum and the presence of pre-cum varies by individual.
Some men don’t produce this type of liquid at all. Most men don’t even notice discharging precum when it happens. More importantly, they do not have any control over it. Early understandings on precum once were that sperm is expected to be part of the fluid.
Can You Get Pregnant Without Penetration?
Can you get pregnant without penetration is a frequent question of young women starting to have sex. However, it all depends on where he ejaculates. If ejaculation takes place near the vagina, then the ejaculate and sperm can enter the vagina and she can get pregnant. For conception to occur, all it takes is for semen to come in contact with the vaginal canal. If ejaculation occurs and semen comes in contact with the vaginal canal, even if he does not completely enter the vagina, then fertilization and conception can occur even without complete penetration. This is rather unlikely, but it is technically possible but highly unlikely.
Can You Get Pregnant While Grinding?
Yes, you can get pregnant with grinding if his ejaculates is near the vagina. Similar to intimacy without penetration, grinding is a form of intimacy that involves going through the motions of having sex without complete penetration.
Because grinding often occurs fully dressed, and in underwear, chances are low that the ejaculate and sperm enter the vagina. Getting pregnant while grinding is highly unlikely if you do it with your pants on. The chances getting pregnant increase when you grind while both are nude.
If both of you are grinding in underwear, there is a low chance that semen could seep through the underwear and gain access to the vaginal canal through her underwear. But if even only one does not wear underpants, then pregnancy chances increase.