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  • Nathan Riley, MD

Obgyno Wino Podcast Episode 47 - Prelabor Rupture of Membranes

Updated: Jul 3

<iframe src="https://anchor.fm/obgynowino/embed/episodes/Ep-47-Prelabor-Rupture-of-Membranes-eg831c" height="102px" width="400px" frameborder="0" scrolling="no"></iframe>"Being born is important You who have stood at the bedposts and seen a mother on her high harvest day, the day of the most golden of harvest moons for her.

You who have seen the new wet child dried behind the ears, swaddled in soft fresh garments, pursing its lips and sending a groping mouth toward nipples where white milk is ready.

You who have seen this love’s payday of wild toiling and sweet agonizing.

You know being born is important. You know that nothing else was ever so important to you. You understand that the payday of love is so old, So involved, so traced with circles of the moon, So cunning with the secrets of the salts of the blood. It must be older than the moon, older than salt."

- Carl Sandburg


2019 Malbec from Espuela del Gaucho



PB#188 - Published January 2018


Five Pearls

1. Management recommendations in PROM/PPROM is dependent on gestational age:

  • >37 0/7 wga => induction/augmentation

  • 34 0/7 - 36 6/7 wga => expectant management or induction/augmentation

  • <34 0/7 wga => expectant management

2. Diagnosis of PROM is based on history and physical: pooling of fluid, pH of vaginal fluid, and ferning on microscopy.

3. Indications for induction/augmentation for both PROM and PPROM include abnormal fetal testing, evidence of intra-amniotic infection, and vaginal bleeding suggestive of abruptio placentae.


4. For PPROM (24 0/7 - 33 6/7 wga) --> antibiotics and steroids should be offered, and magnesium sulfate should be offered at <32 wga


5. The diagnosis of periviable ROM is best followed up with careful counseling around the risks and benefits. It can be managed with induction or expectant management, which, after hospital assessment, can be provided via home care until viability


Background

- Prelabor rupture of membranes (PROM; 37w0d or later w/out signs of labor) = 8% of pregnancies

- Preterm prelabor rupture of membranes (PPROM; 24w0d - 36w6d) = 2-3%

- Periviable prelabor rupture = <1%

- Usually no clear cause, though sub-acute intrauterine infection should be considered, particularly in PPROM - risk factors: history of PPROM, history of PTL, any risk factor for preterm birth (short cervix, cervical or intrauterine procedures like amniocentesis or CVS, 2nd or 3rd trimester bleeding, low BMI, low socioeconomic status, smoking or illicit drug use in pregnancy)


How is PROM diagnosed?

Step 1: perform a sterile speculum exam w/ stirrups (use water instead of lube)

- look for fluid spilling from the cervix or pooling in the vagina (this is a slam dunk!)

Step 2: swab the vagina and posterior fornix to test the pH test of vaginal fluid (amniotic fluid has pH of 7.1-7.3 vs 3.8-4.5 for normal vaginal secretions)

Note: Blood, semen, alkaline antiseptics, lubricants, trichomonas, bacterial vaginosis → high probability of false positive on pH testing (and commercial testing). If the waters were reported to have opened many hours prior, there's likely minimal residual fluid, and thus these tests carry a high probability of false negative


Step 3: smear the swab on a microscope slide and look for arborization ("ferning") of dried vaginal fluid



Ferning

Still not convinced?

- perform an ultrasound and compare to prior evaluations (this method isn't perfect, but comparing your DVP assessment today to a DVP assessment that was performed yesterday could be revelatory) - while you're there, scan the kiddo's bladder --> maybe the fetus is about to pee and replenish that fluid! - fetal fibronectin (FFN), Actim PROM, and many other commercial tests are generally useless (decent negative predictive value but poor positive predictive value due to high false positive rates) - if you desperately need to know if her waters have opened, an old school technique is to inject indigo carmine or fluorescein dye into the amniotic sac; if fluid is leaking, the blue-stained fluid will appear in the vagina in 20-30 min

PERIVIABLE PROM


What outcomes might be expected for periviable PROM?

- in general, the earlier the ROM, the longer the latency

- 40-50% give birth within 1 wk, 70-80% within 2-5 wks

Low likelihood of survival - ↓ death and morbidity with ↑ latency and gestational age (see the NICHD's extremely preterm birth outcomes calculator)

- Persistent oligohydramnios may be correlated with decreased survival with increased risk for adverse neurodevelopmental outcomes as well as fetal deformations

- infrequently in periviable PROM (or PPROM), the leak may seal itself off and the amniotic fluid may reaccumulate

< 22 wga = 14-22% survival rate (deaths split evenly between stillbirths and neonatal deaths)

22 wga = ~58% survival rate

**this survival data is based on retrospective data from cases managed expectantly

Other outcomes - Mom: 14% risk of significant maternal morbidity (including intraamniotic infection, endometritis, abruptio placentae, or retained placenta)

- Mom: 1-5% sepsis

- Baby: Pulmonary hypoplasia (↑ risk with earlier gestational age and ↓ residual amniotic fluid; < 24 wga = 2-20% prevalence, high risk of mortality)

- Baby: Adverse neurodevelopmental outcomes

- Baby: Fetal deformations (Potter-like facies, limb contractures)

- Baby: Other complications of prematurity similar to PPROM

Counseling: periviable PROM

- may be managed as inpatient or outpatient depending on risk factors

- if ROM is diagnosed 20-23w6d gestational age, extensive counseling is warranted and careful consideration of risks/benefits of various options is warranted

Ask yourself

- Is mom super sick?

- Will she become septic if managed expectantly?

- What are her cultural or spiritual beliefs around birth and death?

- if the "do everything" approach is chosen after 23 wga, magnesium sulfate for fetal neuroprotection and GBS prophylaxis should be recommended


PPROM


What are the potential maternal and fetal risks in PPROM?

- 50% give birth within 1 wk

- Mom: risk of intraamniotic infection (15-35%), particularly at earlier gestational ages

- Mom: postpartum infection (15-25%)

- Mom: abruptio placentae (2-5%)

- Baby: complications of prematurity (i.e. respiratory distress, necrotizing enterocolitis)

- Baby: neurodevelopmental impairment and neonatal white matter damage

What to do if you suspect PPROM

- double check gestational age - ultrasound for fetal presentation and EFW - FHR tracing to assess for fetal compromise - assess for intrauterine infection (mom's vital signs, assess for fundal tenderness, etc.) - assess for signs of imminent labor

- culture her for group B strep if her status is unknown - IS SHE CONTRACTING?!


Should I recommend a cervical exam?

- Better question: "will knowing her cervical dilation change my plan?" - Best to avoid is nearly every situation because the more you stick your hand where it doesn't belong, the more likely you'll introduce germs that can lead to intrauterine infection


Management of PPROM

- generally managed as inpatient

- assess for signs of fetal or maternal compromise (e.g. infection or significant FHR tracing abnormalities) - if she and the baby are OK and she is at least 34 wga, you may offer expectant management versus immediately moving towards birth


Note: After 33w6d, induction was traditionally the recommendation; however, a large prospective trial found that expectant management resulted in no difference in neonatal sepsis or composite neonatal morbidity. In fact, immediately moving towards birth was found to be associated w/ higher rates of neonatal respiratory distress and more days in the NICU, though maternal risks of hemorrhage and infection were higher with expectant management. As always...help her weigh risks of prematurity versus benefits of delivery!


PPROM: Should I start antibiotics?

- recommend latency antibiotics if PPROM is diagnosed at <34 wga (this is intended to extended the baby's residency inside the uterus to improve survival rates) - if she goes into preterm labor (<37 wga), switch to GBS prophylaxis - collect a rectovaginal culture for GBS before starting latency antibiotics

- latency antibiotics regimens:

2x days ampicillin 2 g IV q6hr PLUS erythromycin 250 mg IV q6hr THEN 5x days amoxicillin 250 mg PO q8hr PLUS erythromycin 333 mg PO q8hr

- erythromycin and azithromycin are equally efficacious, but the latter is cheaper and better tolerated from GI standpoint

- amoxicillin-clavulanic acid (augmentin) associated with higher risk of neonatal necrotizing enterocolitis (NEC) in some studies, therefore not recommended

- if PCN allergic:

Azithromycin 1 g PO x1 at time of admission PLUS 2x days cefazolin 1g IV q8hr THEN 5x days cephalexin 500 mg PO four times daily

Note: Survival of a newborn may come with SIGNIFICANT morbidities for the newborn. Some people may consider there to be worse things than death, and it's not unreasonable to offer comfort-focused care at time of birth. Remember these points in your counseling...

I've diagnosed PPROM, but then she started contracting. Should I try to stop the contractions?

- Tocolysis may modestly improve latency, but it does not improve outcomes. If anything, it increases the risk of chorioamnionitis.

- Magnesium sulfate may provide some tocoylysis secondarily, but you should be prepared for delivery


What do I do with a cerclage in the event of PPROM?

- jury is still out; removal or retention are both reasonable

- if she goes into labor, remove it!


TERM PROM

What are the likely outcomes in term PROM?

- Without intervention, 95% of women will go into labor within 24 hrs and 80% within 12 hrs of ROM

- 50% give birth within 33 hrs and 95% give birth within ~100 hours **see tables below for more info


Note: the TERMPROM study randomized 5041 women diagnosed with term PROM to: (a) induction w/ oxytocin, (b) expectant management w/ later induction through oxytocin in the event of maternal/fetal compromise or by patient request, (c) induction w/ prostaglandins, or (d) expectant management w/ later induction through prostaglandins. This study also found that some women may view induction more positively than expectant management.

- the longer the time interval between ROM and birth, the greater the risk for intrauterine infection (but let's not forget that longer labor generally means more digital vaginal exams in the hospital, which is an independent risk factor for chorioamnionitis)

- per the TERMPROM study, risk of chorioamnionitis is anywhere from 1-8.6% if managed expectantly (versus 0.1-6% with induction); risk of postpartum fever is 3-3.6% if managed expectantly (versus 2-3% with induction)

- no statistically significant differences in neonatal outcomes (see tables below)



Counseling a patient w/ term PROM

Step 1: counsel her on the risks/benefits of expectant management versus induction of labor (use numbers above!) taking into account any signs of fetal distress or maternal infection Step 2: provide an evidence-based recommendation without using coercive language

Step 3: support her in her decision (she doesn't have to accept your recommendation!)


- outside of signs of maternal/fetal compromise, there is no evidence that rushing to birth the baby improves survival, decreases likelihood of co-morbidities, or decreases risk of neonatal sepsis

- expectant management is associated with higher risk for intrauterine infection and postpartum fever, but it does not carry higher risks for c-section or a threat to the newborn (see Tables 5 and 6 from the TERMPROM study below)


Key table from the TERMPROM study

Key table from the TERMPROM study



If she is takes the expectant management route...

- relax

- monitor for signs of intrauterine infection --> counseling may change if infection suspected - reasonable to await spontaneous labor at home

- whether at home or in the hospital can recommend nipple stimulation, masturbation, or red raspberry leaf tea to encourage spontaneous labor

If she is takes the induction route...

- methods of induction include vaginal prostaglandins, oxytocin infusion, or mechanical methods like cervical ripening balloons - oxytocin and prostaglandins are equally effective, though the latter is associated with higher rates of chorioamnionitis - cervical ripening balloons are associated w/ higher risk of chorioamnionitis compared to oxytocin alone (8% versus 0% in one trial) without any proven benefit

- if she accepted the oxytocin alone route (most popular among OBs), you should allow for 12-18 hrs of adequate contractions before calling it quits and recommending cesarean delivery for "failed induction of labor"


Term PROM: Should I start antibiotics?

- GBS prophylaxis may be warranted if (a) GBS positive by urine culture or rectovaginal swab, (b) GBS status unknown with history of neonatal GBS sepsis in prior pregnancy, or (c) GBS status unknown in setting of prolonged ROM (>18 HRS)



Should I give steroids to promote lung maturity?


- if <34 wga, you should recommend course of steroids (risk versus benefits, particularly if the patient is diabetic)

- a second course can be recommended if prior course was administered at least 2 weeks prior and if birth is expected within 7 days - if 34w0d - 36w6d, risks of occult infection may outweigh benefits of late preterm steroids in the setting of PPROM, but not unreasonable to recommend a single course if they have not received a course previously in this pregnancy and there are no signs of chorioamnionitis


What if the patient has a history of genital HSV, the waters have opened, and she isn't yet in labor?

- management is no different from spontaneous preterm or term labor: if there are active lesions, cesarean birth should be recommended

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