Sperm can reach the egg to potentially fertilize it in as little as 15 to 45 minutes after ejaculation. However, this journey and the process of fertilization may take longer depending on various factors. Sperm can also survive inside the female reproductive tract for up to five days, waiting for the egg to be released. The egg, once released during ovulation, can only survive for about 12 to 24 hours, during which fertilization must occur to result in pregnancy. After fertilization, the fertilized egg takes about 6 days to implant itself into the uterine wall, marking the start of pregnancy.
Key points on timing for conception:
- Sperm swim from the vagina through the cervix and uterus to the fallopian tubes where the egg is fertilized. This can take from a few minutes to several hours.
- Sperm undergo capacitation in the fallopian tube, a process taking up to 6 hours to become capable of fertilizing the egg.
- Sperm can wait in the fallopian tubes for up to 5 days for the egg to be released.
- The egg is viable for fertilization for only 12 to 24 hours post-ovulation.
- Fertilization usually happens within 24 hours of ovulation if sperm are present.
- Implantation of the fertilized egg into the uterus occurs about 6 days after fertilization.
Therefore, pregnancy can result from intercourse occurring several days before ovulation up to about a day after ovulation, depending on sperm survival and timing of egg release.
