The cervix is a narrow ring of muscle at the lower end of your uterus that is the passage through which the baby travels during birth. During pregnancy the cervix changes position quite a few times, and it changes drastically at the end of pregnancy as you begin to labor. Before pregnancy, your cervix is mostly closed, rigid, and approximately 3 cm long. At about 12 days pregnant your cervix rises slightly, lengthens, and softens a little from the extra blood flowing to the area; if you are familiar with the feel, position, and texture of your cervix regularly, you will likely be able to tell when this change occurs and may even suspect your pregnancy before you take a test! During pregnancy, the cervix thickens and becomes sealed shut with mucus referred to as the mucus plug. This mucus plug acts as a wonderful barrier to keep germs and other infections from entering your uterus and possibly harming the baby.
Some women have a condition referred to as an incompetent cervix (medical terms can sound so accusing!). This is when the cervix softens and dilates early, sometimes resulting in a premature birth. The likelihood of this occurring increases if you are genetically prone, have had a D&C procedure, or have had a previously complicated delivery. If this is diagnosed during your pregnancy, there are procedures that can be preformed to attempt to stop or slow the dilation of your cervix including a cervical cerclage. A cervical cerclage is where the cervix is stitched shut, typically with 1-3 stitches. These stitches will be removed at the end of your pregnancy when your doctor determines it is safe for you to resume dilation.
Towards the end of pregnancy, your cervix begins to change again. If you have medical vaginal exams or are familiar enough to examine your cervix yourself you may begin to notice your cervix shifting forward, shortening, softening, and possibly dilating slightly. If you decline vaginal exams, then the first indication of these changes may be when the mucus plug falls out. The mucus plug is also referred to as the bloody show and is jelly-like in texture; if you suspect that the mucus plug has fallen out before 37 weeks call your doctor. These changes can begin weeks, days, or hours before labor starts, and if this is not your first baby, these changes are likely going to begin earlier rather than only hours before labor begins. During labor your cervix will soften and thin; this is referred to as effacement. Your cervix is also opening, or dilating, at the same time. When you are 100% effaced (very thin) and 10 cm dilated (fully open) you are typically ready to deliver your baby, unless your doctor encourages you to wait for a medical reason.
If you have any questions about the cervix feel free to leave a comment. Next week I will post about the letter D... D is for Dehydration.