What is Incompetent Cervix?
The cervix cannot hold the fetus to term because it dilates prematurely.
Pathophysiology
By the 20th week the fetus gains weight and fat. A weak cervix can no longer hold that weight and slowly dilates. A show appears (pink-tinged vaginal discharge), the membranes rupture and amniotic fluid escapes, then uterine contractions and a short labor end in birth of the fetus.
Risk Factors
The cause is not always clear, but these are linked:
- Increased maternal age. Cervical muscle loses elasticity with age.
- Congenital structural defects. Some defects leave the cervix unable to hold the fetus.
- Trauma to the cervix. Prior trauma weakens the surrounding muscle and predisposes to premature dilation.
Signs and Symptoms
- Show. Pink-tinged vaginal fluid signaling the cervix has dilated.
- Increased pelvic pressure. The fetus is descending and pressing on the pelvis.
- Cervical dilation. Visible on exam.
Diagnostic Tests
- Ultrasound. The test of choice when incompetent cervix is suspected. It is often diagnosed only after a pregnancy has already been lost.
Medical Management
There is no medication that reliably stops the dilation. Surgical correction is the mainstay.
Surgical Management
Two cerclage techniques:
- McDonald cervical cerclage. Nylon sutures placed horizontally and vertically across the cervix, drawn together until the canal is only a few millimeters across.
- Shirodkar cervical cerclage. Sterile tape threaded purse-string under the submucous layer and sutured to close the cervix.
Sutures usually come out at the 36th to 37th week so the fetus can be born vaginally, per ACOG, unless a cesarean is planned, in which case the cerclage may be removed at delivery.
Nursing Management
Nursing Assessment
- For painless bleeding, ask whether she feels intense pelvic pressure.
- Inspect and save pads used during bleeding for clots or passed tissue.
- Check for true contractions so you can prepare for birth.
Nursing Diagnosis
- Anxiety related to impending loss of pregnancy as evidenced by premature dilation of the cervix.
Nursing Interventions
- Identify and reduce the factors feeding her anxiety.
- Monitor vital signs for physical responses affecting her condition.
- Convey empathy and build a therapeutic relationship so she can express her feelings.
- Give her accurate information to keep her grounded.
Evaluation
- She appears relaxed and reports reduced anxiety.
- She verbalizes awareness of her anxiety.
- She names ways to cope.
- She uses her support system effectively.
When a pregnancy turns high risk, the care steps up. Work as a team to protect both patients.
Frequently Asked Questions
What is cervical insufficiency? ACOG defines it as the inability of the cervix to hold a pregnancy into the second trimester without contractions or labor. It was formerly called an incompetent cervix.
How is it usually diagnosed? Ultrasound is the test of choice when insufficiency is suspected, often after a painless second-trimester loss or a short cervix is found. A history of prior second-trimester losses also points to it.
What is a cervical cerclage? A cerclage is a stitch placed around the cervix to keep it closed during pregnancy. The two transvaginal techniques are the McDonald (a purse-string suture) and the Shirodkar (placed higher, near the internal os) (ACOG).
When is the cerclage removed? In an uncomplicated pregnancy the stitch usually comes out at 36 to 37 weeks so labor and vaginal birth can proceed. If a cesarean is planned, it may be removed at delivery (ACOG, StatPearls).
What symptoms should prompt evaluation? Pink-tinged discharge (show), increasing pelvic pressure, or a sensation that the baby is pushing down warrant prompt assessment, since dilation can be painless.
Does it recur in future pregnancies? It tends to repeat, which is why a history of second-trimester loss is a key risk factor and why a planned cerclage is often offered in a later pregnancy.