Definition - What does Open Cervix mean?
An open cervix refers to the time in a woman's cycle when the cervical os is open to allow for the entry of sperm or the exit of menstrual blood. Measuring the position of the cervix and whether it is open or closed can help determine when a woman is fertile.
FertilitySmarts explains Open Cervix
A woman's cervix changes position throughout her menstrual cycle and the cervical os opens and closes at particular times. It will open to allow for the passage of blood or sperm and close to prevent bacteria from entering the uterus. The two times in a woman's cycle when her cervix will open are menstruation and ovulation.
During menstruation, the cervix is low, hard, and open to allow blood to flow out of the uterus through the vagina. It may also be angled slightly to one side. Once the woman's menstrual period ends, the cervical os will close again.
Prior to ovulation, rising estrogen levels cause the cervix to draw upwards in the vagina. During ovulation the cervix will be soft (similar to pursed lips), centrally aligned, and the cervical os will be open. This allows sperm to pass into the uterus where it can travel to the fallopian tube to meet the ovulated egg. Women can learn to track their cervical position as an indicator of their fertile window.
After a woman becomes pregnant, her cervix rises up in her vagina and closes tightly. This prevents any bacteria from entering the uterus and harming the developing fetus. The timing of this varies between women so cervical position alone is not an accurate way for women to tell if they are pregnant.