Incompetent Cervix

The cervix is the lowest part of the uterus and normally remains closed until the third trimester. Sometimes the cervix may dilate prematurely without pain or uterine contractions as a result of cervical weakness or Incompetence. If this happens before 24 weeks (~6 months) it is generally referred to as Cervical Incompetence. Dilatation of the cervix occurring after 24 weeks is generally considered to be due to preterm labor and is associated with painful contractions.

What Are the Risks associated with Incompetent Cervix?

A weak cervix that starts to dilate under the pressure of the increased weight of the growing uterus can result in rupture of the membranes and cause leaking of amniotic fluid, which then results in delivery of a baby that may be too premature to survive or who survives but has many problems associated with prematurity.

Risk factors for Cervical Incompetence?

• Multiple D&C’s (either for miscarriages or abortions)
• Damage to the cervix from a previous cone biopsy or LEEP procedure, D&C or D&E
• History of recurrent pregnancy losses
• IVF Pregnancies
• Birth defect of the uterus
• Unknown reasons

How is the Diagnosis of Cervical Incompetence made?

Traditionally cervical incompetence has been diagnosed after a woman has had two second trimester losses in which the cervix opened without any symptoms, and more recently, just having had one loss is sufficient to be given the diagnosis.

Most cases can be identified early with the liberal use of vaginal ultrasound in women who are at risk.  Contemporary research recommends screening for cervical weakness in all pregnant women with risk factors and some data suggests routine universal screening at the time of the 20 week ultrasound.

Sonographic evaluation by a Maternal Fetal Medicine Specialist is essential to prevent misdiagnosis and unnecessary treatment. Ultrasound for cervical evaluation in women at risk of Incompetent Cervix starts around 16 weeks and continues every two weeks until about 24 weeks.

What is the Treatment for Cervical Incompetence?

• Vaginal Progesterone in mild cases.
• Cervical cerclage – a procedure in which the cervix is surgically closed. A cerclage can be placed early in pregnancy on an elective basis or it may need to be placed later in pregnancy on a more urgent/emergent basis (Rescue cerclage).  A Cerclage is removed 3-4 weeks prior to the expected date of delivery to allow for vaginal delivery or can be removed at the time of a scheduled cesarean section.
• Pessary – a device that is placed vaginally to support and close the cervix. This can be done as an outpatient procedure.