Cervical Insufficiency
Cervical Insufficiency
| DRG Category: | 782 |
| Mean LOS: | 2.6 days |
| Description: | MEDICAL: Other Antepartum Diagnoses Without Medical Complications |
Cervical insufficiency, previously known as cervical incompetence, is a condition in which the cervix spontaneously dilates during the second trimester or early in the third trimester of pregnancy, which results in expulsion of the uterine contents. Because this typically occurs in the fourth or fifth month of gestation before the point of fetal viability, the fetus dies unless dilation can be arrested. Incidence of an insufficient cervix has been estimated to be between 0.1% and 2% of all pregnancies. The insufficient cervix has abnormal musculature, with an increased proportion of smooth muscle tissue, and this results in a loss of sphincter tone. When the pressure of the expanding uterine contents becomes greater than the ability of the cervical sphincter to remain closed, the cervix suddenly relaxes, allowing effacement and dilation to proceed.
The cervical dilation that occurs with cervical insufficiency is typically rapid, relatively painless, and accompanied by minimal bleeding. These features help distinguish the syndrome clinically from other causes of cervical dilation or bleeding, such as preterm labor, placental abruption, and placenta previa.
Causes
Normally in pregnancy, the cervix develops increased tensile strength from fusion and recanalization of a distal duct system by 20 weeks’ gestation. Congenital structural defects of the lower genital tract can cause cervical insufficiency depending on the nature of the defect in tensile strength at the cervicoisthmic junction. Such defects were common in women who were exposed to diethylstilbestrol (DES) in utero when their mothers were given the hormone in the 1950s and 1960s to prevent spontaneous abortion. Another important cause of insufficient cervix is previous cervical trauma, such as excessive mechanical dilation during previous obstetric procedures, removal of tissue during previous cervical biopsy, and improperly healed lacerations from previous deliveries. The risk of cervical insufficiency increases with the number of induced abortions. Hormonal factors can also contribute to cervical insufficiency, particularly excessive levels of relaxin, which may cause loss of normal cervical resistance to dilation. Relaxin levels may be higher than usual during some multiple gestations, increasing the risk of cervical insufficiency in these pregnancies.
Genetic considerations
Genetic factors may contribute to cervical insufficiency. The HLA-DR genotype has been associated with recurrent late spontaneous abortions and very preterm births related to cervical insufficiency.
Gender, ethnic/racial, and life span considerations
Any woman of childbearing age may experience cervical insufficiency, although older childbearing women may be at greater risk because they are more likely to have experienced previous trauma to the cervix. Ethnicity and race have no known effects on the risk for cervical insufficiency.
Global health considerations
No data are available.
Assessment
History
Obtain a detailed obstetric and medical history. Ask about the date of the last menstrual period to determine the gestational age of the fetus. Inquire about risk factors related to cervical insufficiency. Women experiencing cervical dilation because of cervical insufficiency may have symptoms that range from feelings of low pelvic pressure or cramping to vaginal bleeding, loss of amniotic fluid, and spontaneous passage of the fetus and placenta. Patients who experience cervical insufficiency frequently report a history of previous second-trimester pregnancy loss, induced abortion, dilation and curettage, cervical biopsy, or prenatal exposure to DES. A history of fertility problems may also be reported.
Physical examination
Many patients are asymptomatic until they experience premature rupture of the membranes. Inspect the perineum for bleeding and fluid. Patients may have pink or dark red spotting, increased vaginal discharge, passage of the mucous plug, or leakage of amniotic fluid. Some report pelvic pressure, cramping, and/or back pain. Cervical insufficiency can be predicted by examining the cervical length with serial transvaginal ultrasound. A cervical length of less than 25 mm between 16 and 24 weeks’ gestation indicates potential cervical insufficiency and a risk of preterm birth. A cervical length greater than 35 mm between 18 and 24 weeks’ gestation is correlated with preterm birth in 4% of patients. Thus, a shortened cervical length is an excellent predictor of cervical insufficiency and eventual preterm birth, especially in high-risk women. Perform a sterile vaginal examination. The cervix is effaced and dilated, with progression in the absence of painful uterine contractions. A bulging amniotic sac or the fetal presenting part may be palpated through the cervix during the vaginal examination.
Psychosocial
The patient who experiences pregnancy loss because of an insufficient cervix is in a state of psychological crisis. If this is a first episode, the patient is likely to be bewildered because of the rapid progress of dilation and the unexpectedness of the loss. In patients who have experienced infertility or previous fetal loss, psychosocial reactions may be complicated by unresolved feelings or cumulative effects of grief experiences. Anger, fear, numbness, guilt, severe grief, and feelings of loss of control are common in both the pregnant woman and her significant others.
Diagnostic highlights
General Comments: Diagnosis is clinically based on a history of habitual second-trimester abortions, painless cervical dilation, and spontaneously ruptured membranes.
| Test | Normal Result | Abnormality With Condition | Explanation |
|---|---|---|---|
| Ultrasound (transvaginal) | Long, noneffaced, closed, internal cervical os; cervical length > 35 mm (at 18–24 wk) | Cervix shortening; dilation of the internal os noted; cervical length < 25 mm (at 16–24 wk) | Cervix will usually shorten or efface before dilation; the internal os dilates before the external os; thus serial imaging can alert one to cervical insufficiency and potential loss |
Primary nursing diagnosis
Diagnosis
Anticipatory grieving related to an unexpected pregnancy outcomeOutcomes
Grief resolutionInterventions
Grief work facilitation; Active listening; Presence; Truth telling; Support groupPlanning and implementation
Collaborative
Medical management depends on the degree of cervical dilation that has occurred at the time the patient is examined. If dilation is progressing rapidly or is complete, preparation is made for delivery of the fetus and placenta. As with any spontaneous abortion, careful evaluation of bleeding is required to detect hemorrhage. Dilation and curettage may be necessary to control bleeding if placental fragments are retained in the uterus.
In less advanced dilation, particularly if the membranes are not ruptured, the patient may be maintained on bedrest in Trendelenburg’s position in an attempt to prolong the pregnancy. Usually, if the woman is no more than 23 weeks’ gestation, cervical dilation is no greater than 3 cm, the membranes are intact, and bleeding and cramping are not present, a cerclage may be used. In this surgical procedure, a purse-string suture is placed in the cervix at the level of the internal os and tightened to prevent dilation by mechanically closing the os. Either the Shirodkar or the McDonald technique can be used to create the cerclage. Prior to placement of the cerclage, an ultrasound is done to confirm a live fetus and to rule out gross fetal anomalies. In any future pregnancies of women with a history of cervical insufficiency, a cerclage may be placed prophylactically at 14 to 18 weeks’ gestation. Prophylactic cerclages have an 85% to 90% success rate of reducing preterm births. For primiparas with risk factors for cervical insufficiency, cervical cerclage may be necessary in only 50% of the cases. All women with risk factors should be assessed with serial transvaginal ultrasound for cervical length. Local anesthesia is usually used during cerclage placement, although regional or light general anesthesia may occasionally be chosen. After a cerclage has been placed, assessment for signs of labor, rupture of membranes, maternal infection, and fetal well-being continues for the remainder of the pregnancy. The cerclage is removed at or near term, with vaginal delivery typically following shortly thereafter. Bleeding, uterine contractions, chorioamnionitis, and ruptured membranes are all contraindications to placement of a cerclage. Transabdominal cerclage is used for women with extremely short cervixes or those who have had a failed transvaginal cerclage. Robotic-assisted laproscopic surgery (RALS) has had some success in preliminary studies.
Recent studies have suggested that intramuscular progesterone supplementation with 17 alpha-hydroxyprogesterone caproate (Makena) may prevent recurrent preterm birth in women with a history of preterm deliveries. Otherwise, pharmacological management of cervical insufficiency is not indicated until after the loss of the fetus and placenta have occurred.
Pharmacologic highlights
| Medication or Drug Class | Dosage | Description | Rationale |
|---|---|---|---|
| Oxytocin (Pitocin) | 10–20 U IV after passage of tissue | Oxytocic | Stimulates uterine contractions to decrease postpartum bleeding |
| RhD immunoglobulin (RhoGAM) | 120 μg (prepared by blood bank) | Immune serum | Prevents Rh isoimmunizations in future pregnancies; given if mother is Rh-negative and infant is Rh-positive |
Independent
Nursing care for patients with cervical insufficiency centers on teaching, psychological support, and prevention of injury to the mother and fetus. If a transvaginal ultrasound is going to be done to measure cervical length, be sure the patient has an empty bladder. Teach the woman about her condition and alert her to the potential for injury of the cervix if labor proceeds with a cerclage in place. Symptoms of labor, rupture of the membranes, and infection should be explained to the woman, with emphasis on the need to report such symptoms promptly if they occur. Consider the patient’s support systems and coping mechanisms if the pregnancy is continuing. Determine if the patient has the social and financial resources to manage a difficult pregnancy and make appropriate referrals if they are needed.
Evidence-Based Practice and Health Policy
Abo-Yaqoub, S., Mohammed, A.F., & Saleh, H. (2012). The effect of second trimester emergency cervical cerclage on perinatal outcome. The Journal of Maternal-Fetal and Neonatal Medicine, 25(9), 1746–1749.
- Medical records of 43 pregnant patients diagnosed with cervical insufficiency and treated with cervical cerclage were reviewed. Among the patients, who were between 18 and 25 weeks’ gestation with singleton pregnancies, 55.8% delivered prematurely and 83.7% had a live birth.
- Histological chorioamnionitis was present in 80% of failures, which was more frequent among patients whose cervix was dilated more than 3 cm or whose membranes were bulging.
- The mean gestational age of birth among patients who were less than 20 weeks' gestation when the cerclage was placed was 28 weeks (SD, ± 2.3 weeks) compared to 33 weeks (SD, ± 1.2 weeks) among patients who were more than 20 weeks when the cerclage was placed (p < 0.05).
- Similarly, patients who were more than 20 weeks at cerclage placement gave birth to babies with higher birth weights (mean of 2,300 grams; SD, ± 120 grams) compared to patients less than 20 weeks at cerclage placement (mean of 1,850 grams; SD, ± 150 grams) (p < 0.05).
Documentation guidelines
- Continuation of pregnancy: Cervical dilation and effacement; station of fetal presenting part; intactness of membranes; absence of bleeding, contractions, or foul discharge; maternal temperature; fetal heart tones and presence of fetal movement if perceptible
- After spontaneous abortion: Pain; color, odor, and amount of bleeding; firmness and position of fundus; bladder function; vital signs
- Indicators of psychological status: Affect, verbalizations of feelings, grieving behaviors, presence of support people, acceptance of anticipatory guidance and resource materials, effectiveness of coping strategies