What is cervical incompetence or incompetent cervix
As your pregnancy advances, the baby grows and puts pressure on the cervix. In normal cases, the cervix remains closed till the last weeks of the third trimester when it starts softening and opening in preparation for childbirth . However, in some women, the increasing pressure from the growing fetus causes the cervix to open up months before term, leading to premature rupture of membranes (PROM) and the waters breaking [2, 3], causing late miscarriages or premature deliveries .
Being responsible for around 25% of all second trimester pregnancy loss [4, 5], the miscarriages due to cervical insufficiency usually occur between weeks 16 and 24, with majority of cases reported between week 18 and week 22 .
Incompetent cervix signs and symptoms
There are often no signs and symptoms  while some women may experience the following:
- Pelvic pressure 
- Back pain
- Pain during urination 
- Abnormal or increased vaginal discharge 
- Period-like cramping 
What causes an incompetent cervix
The exact causes are not yet known, with experts believing it to be occurring due to a combination of certain structural abnormalities and physical conditions, such as an infection or inflammation . The identified risk factors include:
- Congenital uterine abnormalities
- History of a cervical trauma (e.g. laceration during delivery)
- History of multiple second trimester pregnancy losses 
- Dilation and curettage (D&C), a procedure used to detect and treat certain uterine conditions; it may sometimes damage the cervix 
- A cervical surgery or procedure (such as cervical cone biopsy or loop electrosurgical excision procedure/LEEP) [6, 14]
- Exposure to diethylstilbestrol (DES) as an unborn baby; this drug was prescribed to pregnant women until the early 1970s to prevent miscarriages, but is not used anymore due to serious risks to the child later in life 
- Certain hereditary conditions that may affect collagen, a fibrous protein that constitutes the connective tissues of the body 
How common is incompetent cervix
It is a relatively rare complication, occurring in about 1% to 2% of all pregnancies [2, 4]
How is cervical insufficiency diagnosed
In most cases, a cervical incompetence cannot be detected before it causes a miscarriage or preterm delivery . There are no screening methods to predict a woman’s chances of having the complication before pregnancy. The following procedures may be used between weeks 16 and 20  to detect and monitor the problem in women having one or more of the above risk factors or those experiencing some of the symptoms suggestive of an insufficient cervix.
A transvaginal ultrasound may be performed for checking the fetal membranes as well as for measuring the cervical length and determining the dilation and effacement of the cervix . Cervical incompetence is suspected if the cervical dilation is over 2.5 cm and/or the cervical length is less than 20 mm .
An ultrasound can also help to detect if there is a funneling  of the cervix, where the inner end of the cervix begins to open before the outer portion. There is around 80% chance of a premature delivery if the cervix funnels over 50% before the 25th week of pregnancy .
A pelvic exam allows your doctor to evaluate the cervix and detect any change in the shape and size of the uterus and ovaries . It is also useful for checking whether there are any fetal membranes in the vagina or cervical canal as it might confirm cervical insufficiency .
Are there any treatments for an incompetent cervix
Since the preterm delivery occurs before the 20th week of pregnancy, in most cases it is impossible to save the baby as it is too early for him to survive outside the womb .
Monitoring and management
In case of a threatened miscarriage, you may be asked to minimize your physical activity levels, not staying on your feet for extended periods . Regular ultrasound scans are used for monitoring the condition. Your doctor may also recommend avoiding intercourse until the end of pregnancy. Sometimes, complete bed rest is prescribed to minimize the chances of a premature delivery; however, there is a lack of evidence regarding its effectiveness for the purpose . While on bed rest, it is recommended to lay on your left side as much as possible.
It is a surgical procedure where the opening of the cervix is stitched with a strong thread to keep it closed till term . In women with a history of pregnancy loss due to cervical insufficiency, doctors may perform this procedure around the 12th week , putting them on bed rest for at least a few weeks after the surgery. The stitch is removed around week 37 so a normal vaginal birth can be possible . In some cases your doctor may choose to keep it in place for future pregnancies, recommending a c-section delivery instead .
Cervical cerclage has a success rate of 85%-90% for cervical incompetence . However, it also carries the risk of serious complications including cervical laceration, uterine or bladder rupture, preterm labor, PROM and postpartum hemorrhage .
An alternative method is placing a cervical pessary, a small silicone device, inside the vagina to support the cervix and preventing it from opening prematurely .
Tips for minimizing risks of complications
- Consult your doctor regarding a few safe, light exercises you can do while on bed rest to avoid complications like blood clotting in your legs due to prolonged inactivity.
- Ask your doctor if you need to make any changes to your diet to prolong the pregnancy. There are certain foods and spices that are believed to help in cervical ripening; so it may be best to avoid them.
- Maintain a healthy rate of weight gain, especially in case of overweight women, as obesity can further increase the risk of various complications.
ICD-9 and ICD-10 codes
The ICD-9 code used for cervical insufficiency is 622.5 , while its ICD-10 code is N88.3 .
- References +
- http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0014654/, http://www.drugs.com/cg/incompetent-cervix.html