8th Edition APGO Objectives for Medical Students

Premature Rupture of Membranes

Objectives

The student will be able to describe: History, physical findings and diagnostic methods to

confirm rupture of the membranes Factors predisposing to premature rupture of

membranes Risks and benefits of expectant management versus

immediate delivery Methods to monitor maternal and fetal status during

expectant management Predicted outcome when premature rupture of

membranes occurs at a preterm gestation

Preterm PROM

Definition preterm premature rupture of membranes

(PPROM) is defined as amniorrhexis before 37-wk. gestation

premature ROM is defined as rupture of the chorioamnionic membranes prior to the onset of labor

prolonged ROM usually refers to ROM for more than 24 hours

Preterm PROM

Incidence 1-3% - PPROM 10% - PROM (at term)

Preterm PROMDiagnosis History

Gush of fluid Constantly wet

Physical Pooling fluid - posterior fornix Fluid per os Examine with sterile speculum to prevent/limit digital exam of cervix,

to minimize risk of ascending infection and amnionitis Test

Fern - cervical mucus broad fern vs. amniotic fluid narrow fern pH (Nitrazine) - turns blue Cervicovaginal fetal fibronectin > 50 ng/ml

Ultrasound - compatible with SROM

Preterm PROMEtiology Spontaneous

Decreased collagen content Higher surface energy Elevated vaginal pH due to anaerobes, i.e. Bacterial vaginosis Nutritional deficiencies

• Vitamin C • Zinc • Copper

Infections • S. Aureus• Chlamydia • GBS• Neisseria gonorrhoeae • Bacteroides sp

Smoking Iatrogenic

Preterm PROMRisk Factors Previous preterm PROM Incompetent cervix Nutritional factors (see above) Alterations in vaginal pH

Infections Coitus

Smoking Multiple gestation

Previable PPROM (< 24 wk. gestation)

Summary of Published Studies Concerning Preterm Previable PROM Latency (time to delivery)

Mean days 16 Median days 6 Total n = 476

Outcomes Amnionitis 42% Endometritis 15%

Delivery within 7 days 62% 14 days 80% 28 days 90%

Survival < 20 wk 33% (few numbers) 20 - 23 wk 25% (realistic) 23 - 26 wk 50%

Previable PPROM (< 24 wk. gestation)

Prolonged PROM Skeletal deformities

< 26 wk. (27%) 27-33 wk. (6%)

Pulmonary hypoplasia < 26 wk. (27%) 27-33 wk. (1.4%)

Previable PPROM (< 24 wk. gestation)

Complications of prolonged PPROMPulmonary hypoplasia Orthopedic anomalies Potter facies Fetal growth restriction

PROM > 26 wk. and < 34 wk.

Maternal effects Increase in chorioamnionitis Increase in Cesarean delivery

Twins Breech Fetal heart rate decelerations

Spontaneous labor in ~ 90% within 48 hr. of membrane rupture

Increased risk of placental abruption

PROM > 26 wk. and < 34 wk.

Fetal effects Increase in RDS Increase in intraventricular hemorrhage Increase in neonatal sepsis and

subsequent cerebral palsy Increase in perinatal mortality Increase in cord prolapse

PROM > 26 wk. and < 34 wk.

ManagementExpectant - bed rest in hospital Antibiotics

Prophylaxis for prevention of GBS in neonate Prophylactic antibiotics

• May prolong latent period by an average of 5-7d • May reduce maternal amnionitis and neonatal

sepsis

PROM > 26 wk. and < 34 wk.

ManagementSteroids

To enhance fetal lung maturation and decrease RDS

Only one round per NIH ConsensusTocolytics

Randomized trials have shown no pregnancy prolongation

PROM > 26 wk. and < 34 wk.

Management Resealing of membranes

11% show reaccumulation of fluid Once confirmed may discharge patient home

Deliver for Clinical infection Irreversible non-reassuring fetal heart rate pattern Advanced labor Gestational age >34 weeks

PROM > 26 wk. and < 34 wk.

Conclusion Steroids decrease incidence of RDS Tocolytics do not significantly prolong

pregnancy, but may prolong period in which to give steroids

Antibiotics during latency period improve neonatal outcome

ReferencesAdapted from Association of Professors of Gynecology and Obstetrics

Medical Student Educational Objectives, 7th edition, copyright

1997.

Clinical Case

Premature Rupture of Membranes

Patient presentation

A 29-year-old infertility patient with a triplet gestation at 29 weeks gestation presents to the labor and delivery unit of your hospital describing a sensation of “leaking fluid from the vagina” for the last 30-45 minutes. She says she noted her underclothes were damp yesterday, and this morning she noted clear fluid with a small amount of blood leak from her vagina after voiding and wiping her perineum. She denies fever, contractions and abdominal pain, and feels the babies are moving normally.

Patient presentation

Physical examination reveals an afebrile, alert, anxious female. Abdominal examination reveals a 32-centimeter fundal height and a non-tender abdomen and uterus.

How should you further assess this patient?

Teaching points Why is preterm birth risky?

Survival by gestational age* < 23 weeks = 0-12% 23 weeks = 2-36% 24 weeks = 17-56% 25 weeks = 35-85%

*Represents livebirth

Hack and Fanaroff; Semin Neonatol 2000; 5:89-106

Teaching points Why is preterm birth risky?

Survival by birth weight* < 500 g = 1-38% 500-599 g = 4-37% 600-699 g = 27-63% 700-799 g = 43-88%

*Represents livebirth

Hack and Fanaroff; Semin Neonatol 2000; 5:89-106

DiscussionIn addition to the risks of prolonged rupture of membranes in a preterm

gestation, the risk of preterm birth makes PROM a difficult situation. When PROM occurs at a previable gestation, a discussion should be held with the family reviewing the maternal risks of infection against the fetal risks of significant morbidity and mortality during expectant management. When PROM occurs at a preterm, but potentially viable, gestation, discussion should ensue regarding the risk of fetal and maternal infection, as well as risks of preterm birth. This will allow the family to understand the benefit of antibiotics, steroids and expectant management. Careful monitoring of mother and fetus during expectant management should be undertaken, and delivery considered when documented or suspected lung maturity or signs of fetal infection, unrelieved fetal stress or advanced labor are noted. Counseling after the delivery for the recurrence risk of PROM should occur, and modifiable risk factors addressed.

ReferencesAmerican College of Obstetricians and Gynecologists Practice Bulletin # 1,

Premature Rupture of Membranes, Washington, DC: ACOG, June 1998.

Alexander JM, Mercer BM, Miodovnik M, Thurnau GR, Goldenberg RL, Das AF, Meis PJ, Moawad AH, Iams JD, Vandorsten JP, Paul RH, Dombrowski MP, Roberts JM, McNellis D. “The impact of digital cervical examination on expectantly managed preterm rupture of membranes” Am J Obstet Gynecol 2000 Oct;183(4):1003-7.

Mercer BM, Miodovnik M, Thurnau GR, Goldenberg RL, Das AF, Ramsey RD, Rabello YA, Meis PJ, Moawad AH, Iams JD, Van Dorsten JP, Paul RH, Bottoms SF, Merenstein G, Thom EA, Roberts JM, McNellis D. “Antibiotic therapy for reduction of infant morbidity after preterm premature rupture of the membranes. A randomized controlled trial. JAMA 1997, Sep 24; 278(12):989-95.