What is the management plan for cervical thinning at 37 weeks of gestation?

Management of Cervical Thinning at 37 Weeks of Gestation

At 37 weeks of gestation, cervical thinning (shortening) is considered a normal physiological process of labor preparation and does not require specific interventions beyond routine obstetric care. 1

Understanding Cervical Thinning at Term

• Cervical shortening at 37 weeks is part of the normal physiological process of cervical ripening that occurs in preparation for labor 1
• Unlike cervical shortening in the second trimester (prior to 24 weeks), which is associated with preterm birth risk, cervical changes at term (37+ weeks) are expected and do not require preventive interventions 1
• The Society for Maternal-Fetal Medicine (SMFM) guidelines focus on cervical shortening before 24 weeks as a risk factor for preterm birth, not on cervical changes at term 1

Management Approach

Monitoring and Assessment

• Regular prenatal visits with standard cervical assessment should continue 1
• No additional transvaginal ultrasound measurements are necessary at this gestational age unless there are other concerning symptoms 1
• Assessment for signs of labor, including contractions, bloody show, or rupture of membranes should be performed at routine visits 1

Delivery Planning

• No need to expedite delivery based solely on cervical thinning at 37 weeks 1
• Allow for spontaneous labor onset, which is the preferred approach for uncomplicated pregnancies at term 1
• If other indications for delivery exist, standard obstetric protocols should be followed 1

Important Considerations

• Cervical thinning at 37 weeks differs significantly from short cervix in the second trimester:

  • Second trimester short cervix (≤25 mm before 24 weeks) requires interventions like vaginal progesterone 1
  • Cervical thinning at term (37 weeks) is physiological and does not require preventive treatments 1

• Interventions that are recommended for second trimester short cervix but NOT indicated at 37 weeks include:

  • Vaginal progesterone (only indicated for cervical length ≤20 mm before 24 weeks) 1, 2
  • Cerclage (not recommended even for short cervix without prior preterm birth) 1
  • Cervical pessary (not recommended for short cervix) 1

Clinical Pitfalls to Avoid

• Avoid unnecessary interventions for cervical thinning at term (37 weeks), as this represents normal physiology 1
• Do not confuse management strategies for preterm cervical shortening with term cervical changes 1, 2
• Unnecessary tocolytics or progesterone therapy at 37 weeks is not evidence-based and should be avoided 1, 2
• Do not perform unnecessary cervical length measurements via transvaginal ultrasound at 37 weeks, as this will not change management 1