Can Sperm Survive in Menstrual Blood?

It’s possible to become pregnant if you have unprotected sex while on your period because sperm can survive for up to five days in a woman’s reproductive system, even if a woman is menstruating. 

While most women ovulate about two weeks after their menstrual period, it is still possible for a woman to become pregnant at any point in her menstrual cycle, especially women who have irregular periods.

A woman’s monthly menstrual cycle is measured from the first day of the menstrual period until the first day of the next period. The average woman’s menstrual cycle is between 28-32 days, though shorter or longer cycles do occur in some women.

Ovulation usually occurs between Day 11 – Day 21 of the cycle, counting from the first day of the last period. Ovulation usually lasts one day, can happen any time during this window, and it’s not always the same each month. Women who have menstrual cycles on the shorter side tend to be more likely to ovulate closer to day 11. Women with longer menstrual cycles may ovulate occur closer to day 21. 

A woman is most fertile in this window when she is ovulating, and women who are trying to become pregnant use ovulation prediction to determine the optimal time to have intercourse, particularly if they are having difficulty conceiving. Even though most women do not ovulate during their periods, sperm can survive up to 5 days in a woman’s body so it is still possible for an egg to be fertilized if a woman has intercourse during her period.

Many women use ovulation calendars or period tracking apps to help predict when they will ovulate and be most fertile. 

Other methods, including observing cervical fluid, taking daily basal body temperature, and tracking periods can also help you identify when you ovulate.

Contraception (birth control) can be used to prevent pregnancy and should be used even during menstruation if you do not wish to become pregnant. There are numerous types of birth control. Some must be used each time you have sexual intercourse while other work to prevent pregnancy long-term or permanently. Some are available over-the-counter (OTC) and others are available only by prescription.

• Barrier methods
  • Condoms, male and female
• Pericoital birth control, used at the time of sex
  • Diaphragms 
  • Cervical caps
  • Spermicidal sponges 
  • Spermicides
• Hormonal birth control
  • Pill
  • Patch
  • Ring
  • Injectable medroxyprogesterone acetate or DMPA (Depo-Provera)
• Long-acting birth control 
  • Copper-containing intrauterine device (IUD)
  • Levonorgestrel-releasing intrauterine device (IUD)
  • Single-rod progestin implant (Nexplanon)
• Permanent procedures
  • Vasectomy (for men) 
  • Tubal ligation, often referred to as having your “tubes tied" (for women)
• Emergency contraception, used right after unprotected intercourse 
  • “Morning after” pills
    • Hormonal (Plan B One-Step, available without a prescription) 
    • Nonhormonal (Ella)
• “Natural” birth control 
  • Does not require medication, devices, or surgery
  • These methods are the least effective
    • Withdrawal
    • Fertility tracking
    • Breastfeeding (lactational amenorrhea method, or LAM)