Question: Is it possible to get pregnant from a man’s pre-cum?
Many people are curious about pre-ejaculate. After all, educational messages about pre-ejaculate tend to follow the line of thought that suggests men and women are – as they say – “better safe than sorry.”
Pre-ejaculate is fluid that comes from a man’s Cowper’s glands, which are small glands inside a man’s body, by his penis. This fluid helps to lubricate a man’s urethra.
In some men, this fluid is noticeable even when he is sexually aroused – a little bit might come out of his urethra during sexual excitement. In other men, pre-ejaculate is not noticeable. Total volume can range from 0.2mL to 5mL, which is a considerable difference from person to person. 
While several scientific studies have found no sperm at all in pre-ejaculatory fluids (since the come from the Cowper’s glands and glands of Littre, which neither make nor store sperm), at least one study has found that some men seem to have some sperm in their pre-ejaculatory fluids.  This led the research team to speculate that “some men repeatedly leak sperm in their pre-ejaculatory fluid while others do not.” And while the researchers noted that the number of sperm in the pre-ejaculatory samples “was very low”, they also noted that it was unclear how much or how little of a risk of pregnancy the sperm might pose, “except that the chances would not be zero.”
That doesn’t mean that it’s safe to have sex without a condom.
Pre-ejaculate still counts as a sexual fluid and both men’s and women’s sexual fluids can pass sexually transmissible infections, or STIs. Also, while many plan to withdraw their penis before ejaculating, it’s often the case that men mis-time it and ejaculate ends up getting into the vagina. Even the smallest amount of semen can contain many thousands of sperm, and thus pregnancy risk.
By having unprotected sex with another guy, you put yourself at risk for STIs from him. As such, you might consider getting tested for STIs such as chlamydia, gonorrhea, syphilis and HIV.
Ask your healthcare provider about your risk for STIs and which tests would be recommended for you.
If you have had oral, vaginal or anal sex with your boyfriend since having sex with the other guy, then you have also potentially put your boyfriend at risk for STIs.
Talking to your boyfriend about cheating on him takes a good deal of courage, but it might be something you’ll want to consider.
You might also want to examine the reasons why you cheated on your boyfriend and whether there are any lessons you can learn from the experience, including ways that you hope to grow closer to your boyfriend or whether your current relationship is one that you want to be in.
If you do not wish to become pregnant, you might also ask your healthcare provider for information about highly effective methods of birth control such as the IUD, birth control implant, hormonal birth control pills (“the pill”), the birth control shot, and others. Condoms are also highly effective at preventing both pregnancy and STIs.
To learn more about STIs, explore our STI sexual health resources pages or visit the web site of the Centers for Disease Control and Prevention. You can also learn more about pre-ejaculatory fluids and withdrawal from the International Planned Parenthood Federation (“Myths and Facts About Withdrawal”).
Flint, M., McAlister, D.A., Agarwal, A., and du Pleiss, S.S. (2015). Male accessory sex glands: structure and function. In Mammalian Endocrinology and Male Reproductive Biology [Ed. S.K. Singh]
Killick, S.R., Leary, C., Trussell, J., and Guthrie, K.A. (2011). Sperm content of pre-ejaculatory fluid. Human Fertility, 14(1), 48-52.
Reviewed and updated on April 30, 2017 to include additional information about birth control options, research, and resources.