To be pregnant, 2 criteria should be fulfilled:
1. Fusion of sperm with ovum to form a fertilized ovum.
of the fertilized ovum in the Uterus
So, the involvement of sperm is needed.
The pre cum (pre ejaculatory fluid) is also found to have low levels of sperm in it.
So, even if this pre ejaculatory fluid enters into the genital tract, the sperms present in the pre cum can fertilize the ovum.
Hence, resulting in pregnancy
So, it will be better to do a Pregnancy test.
Wishing you a Good Health.
Please let me know if I need to clarify further.
Thanks & take care.