Sperm survive and travel within the female reproductive tract due to a combination of factors, including the properties of cervical mucus and uterine contractions.
The Journey of Sperm
After unprotected sexual intercourse, sperm enter the vagina. The healthiest and most motile sperm navigate the cervical mucus, a barrier that acts as both a filter and a reservoir, extending sperm survival. UCSF Center for Reproductive Health explains that during ovulation, this barrier becomes more favorable to sperm passage. Once past the cervix, uterine contractions propel the sperm further into the fallopian tubes. This journey begins minutes after ejaculation, although the initial sperm may not be the ones that ultimately fertilize the egg. Cleveland Clinic details this process, highlighting that the sperm travel through the vagina, cervix, uterus, and eventually the fallopian tubes.
Sperm Survival Time
Sperm can remain viable within the female reproductive system for up to five days. This viability is significantly influenced by the presence of sperm-friendly cervical fluid. Nova IVF Fertility, Shree IVF Clinic, Mayo Clinic, and Clearblue all confirm a lifespan of up to five days within the female body. The cervical mucus plays a key role in extending this lifespan. Medical News Today notes that semen enters the uterus minutes after ejaculation and can remain viable in the vagina for up to five days.
Factors Affecting Sperm Survival
Several factors influence sperm survival:
- Cervical mucus: Provides a nurturing environment.
- Uterine contractions: Aid in sperm transport.
- Sperm health: Only the fittest sperm complete the journey.
It's important to note that fertilization is only possible as long as the sperm remain alive. This explains the potential for conception even if intercourse occurs several days before ovulation.
