Cervical incompetence (aka cervical insufficiency) is cervical favorability before term. The cervix is thus unable to retain a pregnancy, in the absence of Sx of clinical contractions and/or labor, in trimester 2.

• Dilation (widening) and effacement (thinning) of the cervix begins before a woman's pregnancy has reached term
• It can occur w/o pain or uterine contractions
• Funneling at the internal orifice of the uterus, which is a dilation of the cervical canal at this location

• In normal pregnancy, dilation and effacement occurs in response to uterine contractions
• Cervical incompetence occurs because of weakness of the cervix, which is made to open by the growing presusure in the uterus as pregnancy progresses
• If the responses aren't halted, rupture ot the membranes, and birth of a premature baby can result

• Dx of cervical incompetence can be challenging and is based on a history of painless cervical dilation usually after the 1st trimester without contractions or labor and in the absence of other clear pathology
• In addition to Hx, some providers use assessment of cervical length in 2nd trimester to identify cervical shortening using ultrasound
• However, short cervical length has actually been shown to be a marker of preterm birth rather than cervical incompetence
• Normally, the cervix should be >3cm in length. Common definition is <2.5cm at or before 24 weeks gestation
• Risk of preterm birth is inversely proportional to cervical length:
  • <2.5cm, 18% risk of preterm brith
  • <2cm, 25% risk of preterm birth
  • <1.5cm, 50% risk of preterm birth

• Doesn't require Tx except when it appears to THREATEN a pregnancy
• Cervical cerclage, a surgical technique that reinforces the cervical muscle by placing sutures above the opening of the cervix to narrow the cervical canal. It can be done transvaginally, or through an abdominal incision. It is usually performed between 14-16 weks pregnancy. Sutures are removed between 36-38 weeks to avoid problems during labor
• Cervical pessary, has fewer potential complications, and involves a silicone ring placed at the opening to the cervix early in the pregnancy, and removed later in the pregnancy prior to the time of expected delivery. Further studies required to determine superiority

• During trimester 2 or 3:
  • Miscarriage
  • Preterm

• Cervical incompetence is rare, occurring in only 1% of pregnancies, but causes 22% of miscarriages in trimester 2