Table 48.1 Risk Factors for Cervical Insufficiency
symptomatic, the diagnosis is made when a transvaginal ultrasound detects a short cervical length, defined below 25 mm.21 The ultrasound may be performed on routine follow-up or upon suspicious symptoms. Sonographic surveillance of cervical length is advised every 2 to 4 weeks, up until 24 weeks to allow placement of cerclage if shortening is detected, or up until 32 to 34 weeks to administer antenatal corticosteroids, if significant shortening is detected. In addition to routine cervical length assessment, the cervix should be measured if suspicious symptoms, including mild abdominal pain or cramps, pelvic pressure, and changed vaginal secretion, of cervical insufficiency arise, as had been previously described.
Tests for cervical function—Historically, several methods have been suggested to assist in the evaluation of cervical competence while a patient is in the nonpregnant state. Examples include compliance and ease/resistance of introducing cervical hegar-dilators, cervical traction force appliance of intracervical balloon catheters, hysteroscopy, or hysterosalpingography. However, all of these tests have been proven unhelpful and are not measures of cervical patency,23,24,25 as no comparison to a gold-standard has been made and no associations with outcomes have been sought. Therefore, these adjunct measures are not indicated as part of the evaluation when a women presents with a suspected history of cervical insufficiency or as a primary evaluation. If tests for cervical function are performed, they should not serve as the diagnostic basis for cervical insufficiency.
Proactive maneuvers—When proactively exerting pressure on the uterus, by either fundal pressure, suprapubic pressure, or Valsalva maneuver, cervical shortening and/or effacement and dilatation may worsen with either a shorter cervix, and more advanced dilation or protruding membranes into the vagina may occur.
Tocodynamometry—Attempting to record uterine activity is important part of the evaluation process, serving mainly to rule out preterm labor as the pathological event. In order to establish the diagnosis of cervical insufficiency, tocodynamometry has to show no contractions, or at least infrequent and irregular contractions. Otherwise regular, frequent and possibly painful contractions do not coincide with the diagnosis of cervical insufficiency but rather with preterm labor.
Laboratory indices—Laboratory indices are essentially unchanged in cervical insufficiency and are needed to rule out other possible diagnoses, such as chorioamnionitis, placental abruption, and urinary tract infection. Such events are possibly associated with the pathway of preterm labor and are secondary to cervical dynamics; therefore, they are not part of the pathogenesis of an incompetent cervix.
In utero “sludge” —Ultrasound examinations of cervical length during routine fetal evaluation infrequently reveal not only decreased cervical length but also demonstrate “sludge,” which consists of fetal squamous cell, vernix, leukocytes, and bacteria debris.
treatment modality, but is only considered for the earlier phases of the early parturition syndrome, ie, short cervix. All of these can be aided by lifestyle and behavioral adaptations.