What is an incompetent cervix?
An incompetent cervix (the medical term is cervical insufficiency) is a cervix that painlessly opens (dilates) in the second trimester, long before the baby can survive, without contractions or labor. The cervix is the muscular gateway that is supposed to stay firmly closed until term; when it silently gives way at 16, 18, or 20 weeks, the result is second-trimester pregnancy loss or an extremely premature birth at the edge of viability.
What makes cervical insufficiency different from most obstetric emergencies is that it is predictable and treatable. It tends to recur, it can be watched for with ultrasound, and a cerclage (a reinforcing stitch placed around the cervix) can hold the pregnancy when criteria are met. That is why these cases so often come down to a history that was never taken seriously or a surveillance plan that was never made.
Causes and risk factors
- A prior second-trimester loss or very early delivery, especially one that began with painless dilation. This is the single most important flag in the chart.
- Cervical surgery or trauma: cone biopsy or repeated LEEP procedures for abnormal Pap smears, cervical lacerations from a prior delivery, or repeated mechanical dilation.
- Congenital factors: connective-tissue differences and uterine anomalies.
- A short cervix on ultrasound: cervical length below 25 mm before 24 weeks in a woman with a prior preterm birth is the trigger for ultrasound-indicated treatment.
Signs and why they are easy to dismiss
The cruel feature of cervical insufficiency is how quiet it is. There may be no symptoms at all until the pregnancy is already threatened. When symptoms do come, they are vague: pelvic pressure or heaviness, a low backache, mild cramping, a change in discharge, or light spotting in the second trimester. Each is common in normal pregnancy, which is exactly why the standard of care leans on history and measurement rather than symptoms. A woman with a prior second-trimester loss who calls about pelvic pressure at 17 weeks is not a routine call; she is the textbook case for a cervical check. When that call is met with reassurance instead of an exam, the window for treatment closes silently.
Cerclage: who qualifies and when
ACOG recognizes three pathways to cerclage, each with defined criteria:
| Cerclage type | Who qualifies | When it is placed |
|---|---|---|
| History-indicated | One or more prior second-trimester losses with painless dilation, or a prior cerclage for insufficiency | Prophylactically, typically at 12–14 weeks |
| Ultrasound-indicated | Prior spontaneous preterm birth before 34 weeks, now with cervical length under 25 mm before 24 weeks | When the short cervix is found on surveillance |
| Exam-indicated (“rescue”) | Painless cervical dilation found on exam in the second trimester, often with membranes visible | Urgently, if infection and labor are excluded |
Two implications follow. First, women with a qualifying history should be offered a plan early in pregnancy: either a scheduled cerclage or serial cervical-length ultrasounds (typically every one to two weeks from 16 to 24 weeks). Second, even a first-time presentation can be treatable: an exam-indicated cerclage can rescue a dilating cervix if the exam happens in time. Vaginal progesterone is a related, evidence-supported option for a short cervix without prior preterm birth. The common failure happens earlier: no one assesses the risk at all.
Did anyone act on your history? If a prior loss was in your chart and no cerclage or ultrasound surveillance was offered, that gap, and what it cost, deserves an expert look. Our attorneys review records at no cost to your family.
How the diagnosis gets missed
The recurring patterns in cervical-insufficiency litigation:
- History not taken or not acted on. A prior 19-week loss coded as “miscarriage” and never explored; a prior preterm birth that never triggered cervical-length surveillance.
- Symptoms dismissed. Second-trimester pressure and discharge attributed to normal pregnancy without an exam or ultrasound.
- Surveillance started but abandoned: one normal measurement at 16 weeks, then nothing, in a protocol that calls for serial checks to 24 weeks.
- A short cervix found but not treated: the report filed without a cerclage discussion, progesterone, or a follow-up interval.
- Delayed rescue. Dilation found on a Friday, cerclage scheduled for Monday — in a condition measured in hours.
What happens when it goes untreated
Untreated cervical insufficiency ends in second-trimester loss or extreme prematurity: deliveries at 22 to 26 weeks, where survival is uncertain and survivors face the highest rates of brain hemorrhage, chronic lung disease, and cerebral palsy. An untreated open cervix also exposes the membranes to bacteria, so these cases frequently involve infection and PPROM as the final pathway. For families of surviving children, the measure of the case is the lifetime of care the prematurity now requires; for families who lost the pregnancy, the law in many states recognizes claims for the loss itself.
Was it preventable?
Not every cervical insufficiency outcome is malpractice. A first, unheralded second-trimester dilation can defeat even attentive care, and cerclage is not a guarantee; pregnancies are sometimes lost despite a well-placed stitch. The legal questions are the familiar ones: Did the chart contain a history that required a plan? Was surveillance offered and actually carried out? When a short or dilating cervix was found, was treatment offered promptly? A qualifying history with no plan, or a critical finding with no timely response, is where negligence lives in these cases.
Legal options for families
Claims typically allege failure to obtain or act on the obstetric history, failure to perform cervical-length surveillance, failure to offer cerclage or progesterone when criteria were met, or delay in placing a rescue cerclage. Compensation in cases involving a surviving premature child can cover lifelong care needs; see our settlements guide for how published outcomes are valued. Filing deadlines vary by state, including for claims involving pregnancy loss, which follow different rules in different states.
The right office depends on where the care happened. Banville Law attorneys are licensed in New York and Washington, D.C. (District families can start with our Washington, D.C. birth injury guide); The Weitz Firm attorneys are licensed in Pennsylvania and New Jersey. For care anywhere else, the alliance connects families with its vetted network of local birth injury attorneys.
Frequently asked questions
Can an incompetent cervix be detected before it causes a loss?
Often, yes; that is the point of risk assessment. A history of second-trimester loss or early preterm birth should trigger either a planned cerclage or serial cervical-length ultrasounds between 16 and 24 weeks, which catch most shortening before dilation begins.
Does a cerclage always work?
No. Cerclage meaningfully improves outcomes in properly selected patients, but some pregnancies are lost despite a timely, well-placed stitch. The legal question is whether treatment was offered when the criteria were met.
I had one previous loss at 18 weeks. Should my doctors have done anything differently?
A prior second-trimester loss is the classic flag. Depending on the details, the standard response ranges from early specialist referral and serial cervical measurement to a history-indicated cerclage at 12–14 weeks. A chart note acknowledging the history with no plan attached is a red flag.
Is bed rest a substitute for cerclage?
No. Activity restriction has not been shown to prevent preterm birth in cervical insufficiency and is not a recognized substitute for cerclage or progesterone when treatment criteria are met.
What does a case review cost?
Nothing. The review is free, and these cases are handled on contingency, so attorney fees come out of a recovery or not at all.
Sources
- American College of Obstetricians and Gynecologists. Practice Bulletin No. 142: Cerclage for the Management of Cervical Insufficiency. Obstetrics & Gynecology. 2014;123(2):372–379.
- American College of Obstetricians and Gynecologists. Practice Bulletin No. 234: Prediction and Prevention of Spontaneous Preterm Birth. Obstetrics & Gynecology. 2021;138(2):e65–e90.
- Berghella V, Rafael TJ, Szychowski JM, Rust OA, Owen J. Cerclage for short cervix on ultrasonography in women with singleton gestations and previous preterm birth: a meta-analysis. Obstetrics & Gynecology. 2011;117(3):663–671.
- Owen J, Hankins G, Iams JD, et al. Multicenter randomized trial of cerclage for preterm birth prevention in high-risk women with shortened midtrimester cervical length. American Journal of Obstetrics and Gynecology. 2009;201(4):375.e1–8.
- Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD). Preterm Labor and Birth: Condition Information.
This page is for general education and is not medical advice. Medical facts above are drawn from the cited primary sources; legal statements reflect the reviewing attorneys’ professional experience. Always consult your child’s physician about medical concerns.