An open uterus typically refers to a dilated cervix, which is the uterine opening. This would primarily be a problem during pregnancy when the womb should remained closed while the baby develops inside. During the average woman's menstrual cycle, the cervix will open and close regularly to allow for menstrual flow and to make way for sperm to enter during ovulation. The exact amount a woman's cervix opens and the width of that opening will depend on the individual and whether the woman has had children.
The most common reference to an open uterus relates to a condition known as an incompetent cervix. This condition affects pregnant women and it refers to a cervix that will not remain closed. The cervix is the opening or mouth of the uterus, and it should remain closed and protected by the mucus plug throughout pregnancy until labor approaches. Women with an incompetent cervix are a higher risk of premature labor and uterine infection, both of which are dangerous for the pregnancy.
Incompetent cervix can sometimes be remedied with surgery. This requires a doctor to sew the cervix closed until labor and delivery draws nearer. Women who have this procedure are often encouraged to avoid heavy lifting and other strenuous activities until they give birth to prevent opening the stitches. Some may even be put on bed rest. Once the pregnancy is full term, at around 37 weeks gestation, the stitches are removed and labor is allowed to progress normally.
Unfortunately, many women don't realize they have an open uterus until premature labor begins. It is possible for the cervix to remain closed during the first half of pregnancy and then open slowly as the baby grows and puts more pressure on the opening. If labor is still in its very early stages, medication can often be given to stop contractions before they progress. Additional medications and steroids may also be given to prevent infection and to help hasten the development of the baby's lungs in case a premature delivery is inevitable.
An open uterus can also occur outside of pregnancy, since the cervix goes through many changes throughout a woman's menstrual cycle. During ovulation the cervix produces more mucus and opens wider to allow for the passage of sperm. This makes pregnancy more likely to occur, and many women who are trying to conceive monitor the appearance or feel of their cervix to determine when these changes are taking place. The cervix also opens wider during the menstrual cycle so that blood can pass through.