We all know about the role that a woman’s ovaries, Fallopian tubes, and uterus play in her fertility. But one part of the woman’s reproductive system that isn’t talked about as much is the cervix. Technically a part of the uterus, the cervix is the doorway through which sperm enters on its way to fertilize the egg. If you are trying for a baby, here are some important aspects of the cervix you should know.
The Structure and Composition of the Cervix
The cervix is the lower part of the uterus, shaped like a 2 cm long cylinder. The outer portion, the ectocervix, contains the opening, called the external os. So, the external os opens, or dilates, slightly during menstruation to allow menstrual fluid out - and opens further during delivery to allow the baby to emerge.
The internal portion of the cervix, the endocervix, also contains an opening, the internal os, which opens into the uterus. The endocervix also produces cervical mucus. Cervical mucus protects the reproductive organs from bacteria and infection, and for much of the month, it keeps sperm from entering the uterus. During ovulation, though, the mucus becomes thinner and changes chemical composition, becoming an excellent medium for sperm.
Many women use the thickness and quality of their cervical mucus to track their ovulation cycle.
The ectocervix and the endocervix are not completely separate. In between them is an area called the transformational zone. This is where the tissue of the cervix shifts between the two different types of cells that make up the internal and external areas. This transformational zone actually moves during a woman’s lifetime, developing in the outer cervix at puberty and moving up as she ages.
What is the Role of the Cervix in Fertility
The cervix also plays a more active role in fertility in women. Folds within the cervix called cervical crypts collect and store sperm as it enters the uterus. These crypts then release the sperm gradually over time. Because sperm can fertilize an egg up to 48 hours after release, this gives a longer period for sperm to reach the egg.
Cervical mucus is also known to filter sperm with abnormal morphology. Therefore, abnormally shaped sperm are less likely to reach and fertilize an egg. This filtration may serve as a natural way to make sure that only healthy sperm enters the uterus for conception.
The cervix plays an important role in fertility and health in women, but that role is not always commonly understood. Its position makes it the gate that alternately protects the uterus from danger and allows the sperm needed to conceive. Understanding how it works should give you a better idea of its role as you try for a baby.