Cervical Insufficiency

Definition | Aetiology | Pathophysiology | Risk Factors | Signs and Symptoms | Investigations | Management | References

Definition

Cervical Insufficiency (also known as incompetent cervix) is a condition in which the cervix weakens and dilates prematurely during pregnancy, leading to premature birth or the loss of an otherwise healthy pregnancy, typically in the second trimester.

Aetiology

The exact cause of cervical insufficiency is not always clear, but it can be related to:

• Congenital Factors: Some women may be born with a naturally weak cervix.
• Trauma: Previous surgeries involving the cervix, such as cone biopsy or dilation and curettage (D&C), can weaken the cervical tissue.
• Connective Tissue Disorders: Conditions like Ehlers-Danlos syndrome, which affects connective tissues, may predispose women to cervical insufficiency.
• Intrauterine Procedures: Previous cervical injury during childbirth or surgical procedures like loop electrosurgical excision procedure (LEEP).

Pathophysiology

Cervical insufficiency occurs when the cervical tissue becomes unable to maintain its integrity under the pressure of a growing pregnancy. As the fetus grows and the pressure inside the uterus increases, the cervix begins to dilate and efface (thin out) prematurely, often without pain or contractions. This can lead to premature rupture of membranes and preterm birth.

Risk Factors

• History of cervical insufficiency in previous pregnancies.
• Previous trauma to the cervix, including surgical procedures.
• Multiple pregnancies (e.g., twins, triplets).
• Congenital conditions affecting the cervix or connective tissues.
• Second-trimester pregnancy losses without identifiable causes.

Signs and Symptoms

• Sudden pressure in the pelvis.
• Backache or mild abdominal cramps.
• Vaginal discharge changes (increased or abnormal discharge).
• Vaginal spotting or light bleeding.
• Premature rupture of membranes (water breaking early).
• Painless cervical dilation without contractions.

Investigations

• Transvaginal Ultrasound: The primary method for assessing cervical length during pregnancy. A shortened cervical length (less than 25 mm before 24 weeks of gestation) is suggestive of cervical insufficiency.
• Cervical Assessment: Clinical examination may reveal a soft, dilated cervix.
• History Review: Previous pregnancy outcomes, surgical history, and any connective tissue disorders should be evaluated.

Management

• Cervical Cerclage: A surgical procedure where a stitch is placed around the cervix to reinforce it and help prevent premature opening. It is usually performed between 12 and 14 weeks of gestation in women with a history of cervical insufficiency.
• Progesterone Supplementation: Vaginal progesterone or intramuscular injections may be prescribed to help prevent preterm birth by reducing inflammation and strengthening the cervical tissue.
• Pessary: A device placed in the vagina to help support the cervix and prevent it from dilating prematurely.
• Activity Modification: Some women may be advised to reduce physical activity or be placed on bed rest, although the effectiveness of this approach is debated.
• Monitoring: Regular ultrasounds to monitor cervical length and early signs of preterm labour are crucial in the management of cervical insufficiency.
• Emergency Cerclage: If cervical insufficiency is diagnosed later in pregnancy or if the cervix is already beginning to dilate, an emergency cerclage may be performed, though it carries higher risks.

References

1. NHS (2024) Cervical Insufficiency. Available at: https://www.nhs.uk/conditions/cervical-insufficiency/ (Accessed: 24 June 2024).
2. National Institute for Health and Care Excellence (2024) Preterm Labour and Birth. Available at: https://www.nice.org.uk/guidance/ng25 (Accessed: 24 June 2024).
3. Royal College of Obstetricians and Gynaecologists (2024) Green-top Guideline No. 60: Cervical Cerclage. Available at: https://www.rcog.org.uk/en/guidelines-research-services/guidelines/gtg60/ (Accessed: 24 June 2024).

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