94 Preterm premature rupture of membranes
Pathophysiology
When membranes rupture before the onset of labor it is called premature rupture of membranes (PROM). Preterm premature rupture of membranes (PPROM) is the leakage of amniotic fluid before term (38-41 wk gestation). From early in pregnancy, the slightly alkaline (pH 7.0-7.5) amniotic fluid is produced within the amniotic sac. As pregnancy advances, fetal urine significantly contributes to the volume. Fetal breathing and swallowing reabsorb the amniotic fluid, which is formed, absorbed, and replaced within a 4-hr period. Amniotic fluid volume at term is approximately 500-1500 mL. It provides an environment that protects the fetus from trauma and injury, provides even distribution of temperature, contains an antibacterial substance, and enables the fetus to move and develop without pressure. It also plays a major role in fetal development of the lungs and kidneys. Although the cause of PPROM is unknown, it is considered the cause of one-third of the preterm births before 36 wk gestation (Jorgensen, 2008; Weitz, 2001). Risk for a preterm birth is high. The majority of patients with PPROM deliver from within 24 hr to 2 wk of onset.
Health care setting
The woman may be evaluated in the health care provider’s office or clinic. She is managed by obstetricians or perinatologists as an outpatient or inpatient, depending on week of gestation. Hospital sites may vary depending on gestational age and ability of the hospital to provide care for a high-risk pregnancy and neonate. Before 23 wk gestation, PPROM management is planned around the risks for infection and fetal-developmental anomalies. Parents are usually involved in decision making.
Assessment
Patients may have difficulty determining the presence of ruptured membranes. Symptoms may be obvious or subtle. Leaking amniotic fluid can be confused with leaking urine. Consider carefully any complaint of watery vaginal discharge or sudden gush of fluid. Determine the timing of initial loss of fluid. On some occasions, leakage of amniotic fluid may stop, or it may resume without signs of infection.
Vaginal discharge:
Patients may experience a “sudden gush” or sensation that something “popped” followed by a constant slow leakage of clear, watery fluid from the vagina. The fluid may be blood-tinged or meconium-stained. The amount and odor of fluid should be evaluated. The patient may state that her underwear is wet or that she needs to wear a sanitary pad. Vaginal bleeding may accompany PPROM and range from light pink spotting to bleeding as with a heavy menses.
Backache:
May or may not be present with PPROM. In the presence of infection, there may be low lumbar/sacral pain that is deep tissue in nature or a dull, aching sensation that may radiate around the hips to the lower abdomen/pelvic area. If abruptio placentae is present with PPROM, the back pain may be mild or severe.
Abdominal pain/cramping or uterine cramping contractions:
There may be a feeling of pelvic pressure or fullness, menstrual-like cramping, or contractions. Aching thighs may accompany uterine cramping. In the presence of infection, the patient may complain of abdominal/uterine tenderness or pain. If abruptio placentae accompanies PPROM, the pain may be mild or severe.
Complications—fetal:
Risks to the fetus depend on gestational age at the time of PPROM, the severity of PPROM (the amount of amniotic fluid remaining,), and the presence of infection.
Physical assessment:
In most cases, the cause of PPROM is unknown and there is no forewarning. Therefore, it is important to evaluate changes in vaginal discharge. A timely diagnosis of PPROM is critical to optimal fetal outcomes.
Risk factors:
Maternal infections precede PPROM 30%-40% of the time (urinary tract infections [UTI], genital tract infections such as Chlamydia trachomatis, gonorrhea, bacterial vaginosis, or trichomoniasis; chorioamnionitis [intraamniotic infection]; group B streptococcus), low socioeconomic status, smoking, multiple gestation, incompetent cervix (painless cervical dilation before term without contractions), previous history of PPROM, diethylstilbestrol (DES) exposure, amniocentesis, chorionic villi sampling (CVS), coitus, poor nutrition, bleeding in pregnancy, polyhydramnios (excess of amniotic fluid), cervical cerclage (a suture used for holding the cervix closed during a pregnancy), previous cervical laceration or surgery, placental abruption (abnormal separation of the placenta from the wall of the uterus before delivery), history of mid-trimester pregnancy loss, cocaine use, hypertension, diabetes, and Ehlers-Danlos syndrome (a group of inherited connective tissue diseases).
Diagnostic tests
Sterile speculum examination:
A sterile speculum is inserted into the vagina to visualize amniotic fluid leaking from the cervical os or pooling of amniotic fluid in the vagina. This fluid is tested with Nitrazine paper. If positive for amniotic fluid, the paper will turn from yellow to dark blue or green-blue, and the pH will be greater than 6.0. False-positive results may be seen in the presence of semen, blood, vaginal infections, or alkaline antiseptics. Using a cotton swab, a sample of vaginal fluid is taken from the posterior vaginal fornix (the posterior space below the cervix) and examined under the microscope for the presence of a ferning pattern that amniotic fluid makes when it dries on a slide. A digital examination of the cervix is not recommended in a patient with suspected PPROM, who is not in labor.
External uterine and fetal monitoring:
External uterine monitoring is done to evaluate fetal well-being and uterine contraction presence, frequency, and duration. Abnormal fetal heart rate patterns (decreased variability, moderate-to-severe variable decelerations, and late decelerations) suggest fetal compromise, which can be caused by umbilical cord compression, cord prolapse, or infection that may accompany PPROM.
Obstetric ultrasound:
Abdominal ultrasound is used to confirm gestational age, calculate amniotic fluid index (AFI) and biophysical profile (BPP), rule out multiple gestation, and determine placental location and fetal presentation. A normal value for the AFI is between 10 and 20 mL of amniotic fluid. A normal rating on the BPP is 6-8 of 10.
Amniocentesis:
Transabdominal aspiration of remaining amniotic fluid to test fetal lung maturity and the presence of chorioamnionitis.
Intrauterine dye test:
Done only if other tests are inconclusive in determining PPROM or to document that the membranes have sealed over. Resealing is rare, but it can occur. Under ultrasound guidance a diluted solution of indigo carmine dye is inserted with a spinal needle transabdominally into the uterus. The patient is observed for passage of blue fluid from the vagina, which would indicate rupture of membranes.
Blood Rh factor and antibody screen:
This test should be a part of the routine prenatal screening. In patients with no prenatal care who have PPROM, this laboratory test is performed on admittance to determine need for administration of Rh-immune globulin to an Rh-negative mother if her newborn is Rh positive.
Nursing diagnosis:
Risk for infection
related to bacterial spread (often from upward movement of vaginal bacteria)
Desired Outcome: The amniotic fluid is clear without offensive odor and maternal temperature remains less than 99.5° F.
| ASSESSMENT/INTERVENTIONS | RATIONALES |
|---|---|
| Assist health care provider with sterile speculum examination, collection of amniotic fluid, Nitrazine paper test, and observation of ferning by microscope. | These assessments are able to confirm the diagnosis of PPROM. |
| Assist with collecting specimens from amniocentesis or vaginal secretions for laboratory culture. | Group B streptococcus, Chlamydia trachomatis, gonorrhea, bacterial vaginosis, or trichomoniasis organisms are common causes of maternal vaginal tract infections and chorioamnionitis. |
| After PPROM has been confirmed, begin maternal assessments: monitor maternal vital signs q2-4h; palpate uterus for tenderness; and observe vaginal secretions for color, amount, and odor q8h. | Fever, uterine tenderness, and changes in vaginal discharge are signs of infection. Prompt notification of signs to the health care provider may decrease the risk of further compromise to the fetus or mother. |
| Apply external fetal heart rate (FHR) monitor and assess with nonstress test (NST) q8h. | Fetal tachycardia is a sign of infection. A nonreactive NST result is associated with infection. Late decelerations in labor are a sign of a compromised fetus struggling with oxygenation demands during labor. |
| Arrange for other tests of fetal well-being (e.g., BPP, amniocentesis for lecithin to sphingomyelin [L/S] ratio, and phosphatidyl glycerol [PG], and ultrasound for AFI). | BPP assesses deviations in growth and development and assesses for subclinical infection. |
| Collect serial maternal specimens of blood for complete blood count (CBC) and urine for urinalysis as prescribed by the health care provider (e.g., daily). | White blood cell differential rises with infection. Bacteria is present in the urine if a urinary tract infection (UTI) develops. |
| Administer antibiotics as prescribed by the health care provider. | Prophylactic antibiotics prevent or reduce effects of maternal-fetal infections and may reduce morbidity and prolong the pregnancy. |
| Instruct and assist patient with good hygiene: frequent hand hygiene, wiping perineum from front to back, and changing the peripad q2h (if a pad is worn). | These practices prevent spread of microorganisms from the environment to the genital area. A moist, warm peripad fosters bacterial growth. |
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