Cervical Incompetence: Complete Guide
Cervical incompetence — now more often called cervical insufficiency by UK clinicians — happens when the cervix begins to open (dilate) and shorten too early in pregnancy, without the contractions you'd expect with labour. It's a recognised cause of second-trimester loss and premature birth, but it's also a condition that can be actively monitored and treated, and many women who are diagnosed and treated go on to carry to term.
What causes it
The cervix normally stays firm and closed until labour begins, held in place by connective tissue. Cervical insufficiency can happen when that tissue is weaker than usual. Known risk factors include:
- A previous late miscarriage or premature birth, particularly if it happened painlessly or very quickly
- Previous surgery on the cervix, such as a LLETZ (large loop excision) or cone biopsy for abnormal cervical cells
- A structural or congenital variation in the shape of the womb or cervix
- Carrying twins or a multiple pregnancy, which puts extra pressure on the cervix
- Significant trauma to the cervix during a previous delivery
In some cases, no clear cause is ever found, which can feel unsettling, but it doesn't change the fact that monitoring and treatment options are available.
How it's picked up and monitored
Because early cervical shortening often causes no obvious symptoms, it's usually identified in one of two ways:
- History-based: if you've had a previous late miscarriage or premature birth that fits the pattern, your team may recommend closer monitoring or preventative treatment from early in this pregnancy
- Scan-based: a transvaginal ultrasound measures cervical length, usually done between around 16 and 24 weeks in women considered at higher risk, so any shortening can be caught early
Some women have no risk factors and no symptoms at all, and the first sign is a shorter-than-expected cervix picked up incidentally on a routine scan.
Treatment options
The main treatments your obstetric team may discuss include:
- Cervical cerclage (a stitch): a stitch placed around the cervix, usually between 12 and 16 weeks for women with a strong history, or later if placed because of a shortening cervix seen on scan. It's typically removed around 36–37 weeks or when labour starts.
- Vaginal progesterone: pessaries or gel that may be recommended if a short cervix is found on scan, to help reduce the risk of preterm birth.
- A cervical pessary: a small silicone ring some units use as an alternative or addition to a stitch.
- Reduced activity and close monitoring: your team may suggest more frequent check-ups and advice on activity levels depending on your individual situation.
With appropriate treatment and monitoring, many pregnancies affected by cervical insufficiency go on to reach term or near-term.
Frequently Asked Questions
What is cervical incompetence?
It's when the cervix shortens and begins to open earlier than it should in pregnancy, without contractions — most often noticed in the second trimester. It's diagnosed either because of a relevant pregnancy history or because a scan shows the cervix is shorter than expected, and it's a manageable condition rather than an automatic cause for alarm.
Can a cervical stitch save my pregnancy?
A cervical stitch (cerclage) is a well-established treatment that significantly improves outcomes for many women with cervical insufficiency, and most pregnancies treated with a stitch reach full term or close to it. It isn't guaranteed to prevent every preterm birth, but it's one of the most effective interventions available and your team will discuss timing and suitability based on your history.
Will I need a stitch in every future pregnancy?
Not necessarily — it depends on why the cervix shortened and how the pregnancy where it was treated went. Some women need a stitch again in future pregnancies, while others are monitored with scans instead and only treated if shortening is seen; your obstetric team will plan future pregnancies individually based on your history.
This article is for informational purposes only and does not constitute medical advice.
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