Understanding cervical incompetence in pregnancy: Causes, signs, and surgical interventions

Cervical incompetence, also known as cervical insufficiency, refers to a condition in pregnancy where the cervix, the passage between the uterus and the birth canal, becomes weak. This weakening of the cervix can result in it starting to open up (dilate) or become thinner (efface) before the pregnancy has reached its full term.

Cervical incompetence can have significant effects on pregnancy. It may lead to a miscarriage in the second trimester or result in premature birth. Premature birth can be especially concerning because it may cause problems for the newborn due to their premature arrival, known as neonatal distress.

Understanding Cervical incompetence

Cervical incompetence can be caused by different factors, which can be divided into two categories: acquired causes and inherited causes.

Acquired causes include previous injuries to the cervix or cervical surgeries, such as biopsies or amputations performed for cervical abnormalities. Also, a history of dilation and curettage (a medical procedure) can be a contributing factor. A prior 2nd-trimester miscarriage should raise a strong suspicion of insufficiency.

Inherited causes encompass inherent weakness in the cervix or any abnormalities in the uterus, which can result in cervical insufficiency. However, the exact underlying cause of cervical insufficiency remains uncertain.

Signs of Cervical Incompetence During Pregnancy

● Pelvic Pressure: Expectant mothers might experience a sense of pressure in the pelvic region. This discomfort can be an indicator of cervical insufficiency.

● Vaginal Discharge: Unusual vaginal discharge can be another telltale sign. It's important to pay attention to any changes in the type or amount of discharge.

● Constant Backache or Uterine Contractions: Continuous backaches or frequent uterine contractions could signal cervical incompetence. These sensations may be persistent and require careful monitoring.

● Spotting or Bleeding: Perhaps one of the more concerning symptoms, spotting or bleeding, can occur with cervical insufficiency. Any presence of blood should be promptly addressed by a healthcare professional.

Evaluating Cervical Incompetence

Ultrasonography: Healthcare providers often employ ultrasonography to assess the length of the cervix. If the cervical length measures less than 2.5 centimetres, it raises concerns about potential cervical insufficiency.

Surgical Intervention with Cervical Cerclage: In cases of classical cervical incompetence, medical professionals may recommend a surgical procedure called cervical cerclage. This procedure involves strengthening the weak cervix by using a purse-string suture. By reinforcing the cervix, cerclage aims to reduce the risk of complications and provide additional support during pregnancy.

When is cervical cerclage typically done?

Scheduled at around 14 weeks: Typically, healthcare professionals recommend performing the cervical cerclage procedure at around 14 weeks into the pregnancy. This timing is chosen because it provides a balance between early intervention and ensuring the safety and stability of the pregnancy.

Previous miscarriage due to cervical insufficiency: In cases where a woman has experienced a miscarriage in a previous pregnancy due to cervical insufficiency, the cerclage can be planned prior to pregnancy through a laparoscopic approach which has a success rate of 80 to 90 per cent.

Types of Cervical Cerclage

Interval Cerclage: Interval is a better option as during pregnancy cerclage can be riskier. However, if missed it can be planned 2 weeks before the gestational age at which the previous pregnancy was lost. This tailored timing aims to minimise the risk of recurrence and provide added support.

This type of cerclage is performed before the conception of the next pregnancy, especially when the mother has known risk factors for cervical insufficiency or has experienced a previous miscarriage due to this condition. Interval cerclage is a proactive step to reinforce the cervix's strength and reduce the risk of complications in future pregnancies.

Prophylactic Cerclage: During pregnancy, if the viability of the pregnancy is confirmed, healthcare providers may plan for prophylactic cerclage at around 14 weeks. This approach is designed to provide additional support to the cervix during the ongoing pregnancy.

Rescue Cerclage: In cases where evidence of cervical insufficiency is already present in the current pregnancy, indicating that the cervix has started to open up, rescue cerclage may be recommended. The aim is to prevent further progression towards abortion or preterm birth by applying a stitch to strengthen the cervix.

For individuals with preexisting uterine abnormalities or a history of miscarriage, interval cerclage performed via laparoscopy may be the most suitable option. This specialised approach not only reinforces the cervix but also helps prevent preterm births or future miscarriages. It's worth noting that a cerclage can be placed up to 28 weeks into pregnancy, but earlier intervention often yields better results.

How does cervical cerclage impact delivery?

There are two common types of vaginal cerclage procedures: the Shirodkar and McDonald techniques. In cases where these stitches have been placed vaginally, there is a possibility that they can be carefully removed when it's time for delivery. If the cerclage stitches were inserted vaginally and can be safely removed when the time comes for childbirth, a normal vaginal delivery may be considered as an option for the mother. In contrast, if a laparoscopic cerclage has been performed, the mode of delivery typically leans towards a Cesarean section or C-section.

(Authored byDr B Ramesh, Chief Obstetrician and Gynaecological Laparoscopic Surgeon, and Founder and Medical Director, Altius Hospitals)

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