Premature Rupture of Membranes
The terminology pertaining to premature rupture of membranes (PROM) can be confusing .
· Premature Rupture of Membranes (PROM) is rupture of the membranes (ROM) prior to the onset of labor.
· PROM is used appropriately when referring to a patient who is beyond 37 weeks of gestation, has presented with spontaneous rupture of the membranes (SROM), and is not in labor.
· Preterm Premature Rupture of Membranes (PPROM) is ROM prior to the onset of labor in a patient who is at less than 37 weeks of gestation.
· Prolonged ROM is any ROM that persists for more than 24 hours.
Incidence of PROM is approximately 10% of pregnancies.
Patients with PROM may present with chief complaints of leaking fluid, vaginal discharge, vaginal bleeding, and pelvic pressure, but they are not in labor.
The diagnosis of PROM can be made by:
- looking for pooling of fluid in the vagina or leakage of clear fluid from the cervix
- and by ferning or arborization of this vaginal fluid when allowed to dry on a glass slide and viewed with a light microscope
- and/or contacted with Nitrazine paper (which turns blue in contact with the vaginal fluid). Blood contamination of the Nitrazine paper can invalidate results.
- If the diagnosis is still in question, the amniotic fluid index (AFI) can be helpful.
- If doubt still exists, transabdominal instillation of 1 mL of indigo carmine dye in 9 mL of sterile saline into the amniotic cavity under ultrasound guidance and observations of staining on a vaginal tampon or a sanitary pad should alleviate any question of ROM.
NB. Avoid a digital cervical examination unless prompt or immediate delivery
Ninety percent (90%)of patients with PROM enter spontaneous labor within 24 hours.
The major question regarding management of these patients is whether to allow them to enter labor spontaneously or to induce labor.
- The management of these patients depends on their desires.
- The major maternal risk at this gestational age is intrauterine infection.
- The risk of intrauterine infection increases with the duration of ROM.
- Evidence supports the idea that induction of labor, as opposed to expectant management, decreases the risk of chorioamnionitis without increasing the cesarean delivery rate.
- If a patient desires expectant management, this should be at hospital with complete bed rest and continuous fetal heart monitoring is the safest method. However, intermittent monitoring with some ambulation, which includes bathroom privileges may be applied. šWith an unfavorable cervix, expectant management decreased the cesarean delivery rate and length of labor without increasing infectious morbidity.
- Induction of labor with oxytocin or prostaglandin E2 gel and expectant management resulted in similar rates of cesarean delivery and neonatal infection.
- Induction with oxytocin, however, resulted in a lower risk of maternal infection (endometritis) when compared with expectant management.
NB Expectant management at home may increase rates of cesarean section, numbers of neonates admitted to the NICU for >24 hours, neonatal sepsis.
Premature Preterm Rupture of Membranes (PPROM)
PPROM is far more complicated than PROM at term.
Important factors affecting neonatal outcome:
· Gestational age at delivery
· Estimated fetal weight
· Presence or absence of infection
· Whether a course of steroids has been completed
Indications for termination of pregnancy:
- Overt intrauterine infection
- Presence of fetal distress
- Maternal indications for delivery e.g severe pre-eclampsia, antepartum hemorrhage…etc.
The gestational age and the presence or absence of an intraamniotic infection (chorioamnionitis) determine the initial management of patients with PPROM.
If a patient has evidence of intraamniotic infection by:
· clinical examination:
- Maternal temperature >38°C,
- fetal tachycardia,
- fundal tenderness,
- foul or purulent vaginal discharge,
- maternal tachycardia,
- elevated C-reactive protein level)
· Or by amniocentesis (positive Gram stain finding, glucose <20 mg/dL, positive amniotic fluid culture results for aerobic or anaerobic organisms or Mycoplasma species)
Institution of broad-spectrum antibiotics and delivery are necessary,
regardless of gestational age.
· If no evidence of infection the overall goal is to manage the patient expectantly until she has reached a gestational age beyond which neonatal morbidity and mortality is minimal and to achieve delivery before the mother and/or her fetus become infected.
· No uniform agreement has been reached on the optimal gestational age (regardless of local NICU statistics) at which delivery should be undertaken.
· Each institution must have an idea of how well neonates at various gestation ages do at that particular institution e.g If a patient is at more than 32 weeks of gestation and has documented fetal lung maturity, delivery is recommended and if a patient has reached 32-35 weeks’ gestation and has documented ROM, delivery in the absence of documented pulmonary maturity may be considered in institutions with a NICU equipped to manage the complications of prematurity.
1- Institution of broad-spectrum antibiotics is advantageous
Use of antibiotics has been associated with prolongation of pregnancy and reduction in infant and maternal morbidity.
- ampicillin (2 g IV q6h) and erythromycin (250 mg IV q6h) for 48 hours, followed by amoxicillin (250 mg PO q8h) and erythromycin base (333 mg PO q8h) for 5 days, for a total of 7 days of antibiotics.
- An alternative is ampicillin/sulbactam (3 g IV q6h) for 48 hours, followed by
amoxicillin/clavulanate (250 mg PO q8h) for 5 days, for a total of 7 days
- A broad-spectrum cephalosporin or clindamycin may be
substituted in patients who are allergic to penicillin.
NB. Prolonged antibiotics offer no advantages and may promote the emergence of
resistance (eg, ampicillin-resistant Escherichia coli).
2- Use of steroids
- It is recommended to use corticosteroid for women with PPROM prior to 30-32 weeks gestation in the absence of clinical chorioamnionitis.
- The dose is betamethasone 12 mg IM qd for 2 days. No evidence supports the use of subsequent courses of this therapy.
3- Fetal Monitoring
Perform antepartum fetal surveillance at least daily, which may consist of
a nonstress test (NST) and Amniotic Fluid Index (AFI).
No evidence supports one form of testing over another or any specific frequency.
4- Tocolytic use
- Tocolytics may be used to prolong gestation long enough to complete a
course of corticosteroids (betamethasone 12 mg IM qd for 2 d).
- Be absolutely certain that an intraamniotic infection is not present before
5- pelvic rest and cervical examination
- Pelvic rest is of utmost importance, as the risk of ascending infection
increases not only with the duration of ruptured membranes but also with
manipulation of the cervix.
- Examine the cervix with a sterile speculum and not digitally.
- Furthermore, there is no need for frequent cervical examinations in a patient who is without complaints of regular uterine contractions, pelvic pressure, vaginal bleeding, or other signs and/or symptoms of labor.
- The single exception is in the patient who has advanced cervical dilation and/or a nonvertex presentation. These patients are at increased risk for umbilical cord prolapse and may require more frequent cervical examinations (sterile speculum) to assess whether further cervical dilation has occurred.
- If the patient has advanced cervical dilation (ie, enough dilation to allow an umbilical cord to prolapse) and/or a nonvertex presentation, continuous fetal heart rate monitoring may be necessary.
- In many instances of cord prolapse, the only sign may be severe variable decelerations or a prolonged deceleration in the fetal heart rate. This is difficult to diagnose with intermittent fetal heart rate monitoring.
- Again, any evidence of intraamniotic infection should prompt a move toward delivery.
- Practitioners should have a low threshold for diagnosing infection in light of recent evidence documenting how much more poorly neonates who are infected do compared to neonates who are not infected.
PROM between 13 and 26 weeks
* Chorioamnionitis occurs in 30-60% of patients with second-trimester PPROM.
The risk of infection increases with duration of ROM and an AFI less than
2.0 cm. Frequent examinations are necessary to ensure maternal safety.
* Patients must be educated about the warning signs of intraamniotic
infection, and they must take their temperature 3 times a day at home.
These patients do not require hospitalization if no evidence of vaginal
bleeding or infection exists. Patients may consider admission for
inpatient management at 24 weeks, the juncture currently considered the
point of viability at most institutions.
* Pulmonary hypoplasia is the most serious fetal complication and can be
lethal. The presence of severe (AFI <2.0 cm), prolonged (>14 d), and early
(<25 wk at onset) oligohydramnios has been associated with a neonatal
mortality rate greater than 90%.
· ROM during the canalicular stage (13-25 wk) has the most dismal prognosis. The diagnosis of pulmonary hypoplasia is made at autopsy by weighing the lungs. Several schemes exist for predicting pulmonary hypoplasia antenatally using lung lengths and/or thoracic circumference ratios, but the functional capacity of the lung cannot be predicted, only the amount of tissue present.
· Midtrimester (13-26 wk) PPROM has a dismal prognosis. Survival varies with gestational age at diagnosis (from 12% when diagnosed at 16-19 wk to as much as 60% when diagnosed at 25-26 wk). Until viability, maternal well-being should be of paramount concern.