Flashcards in Chapter 17: PROM Deck (18)
When is amniotic fluid produced and when is it mostly baby piss?
Amniotic fluid is produced continuously with it being mostly fetal urine production starting at 16 weeks.
Loss of amniotic fluid is bad because:
Loss leads to compression of umbilical cord and decreased placental blood flow
PROM happens how often?
PROM - Rupture of membranes before labor has begun, happens 8% of the time in term labor (>37 weeks) and 30% of the time with preterm labor, and is one of the leading causes of pre-term labor.
Major complication of PROM
Major complication: Intrauterine infection due to lower infections being able to get to the fetus
PROM leading to preterm labor has secondary effects on fetal development due to early delivery. What do we worry about the most?
Preterm PROM between 16 and 26 weeks complicates 1% of all pregnancies.
24-26 weeks can generally survive but they will have a lot of effects of prematurity. If there is pulmonary hypoplasia, they cannot be properly ventilated and will get barotrauma from the amount of air you're forcing in, on top of their hypoxia.
Can infection cause PROM?
Causes: Potentially infection as metabolites from bacteria may weaken the membranes
Risk factors for PROM?
Risk factors: Risk of PROM doubled in smokers during pregnancy. Prior PROM (2x), short cervical length, prior pre-term delivery, polyhydramnios, multiple gestations, bleeding in early pregnancy.
Why is chorioamnionitis so bad and what do we do about it?
a) Chorioamnionitis is a big deal. Inflammatory mediators going up in the fetal environment can cause periventricular leukomalacia, cerebral palsy, and neurological abnormalities. Fever, tachycardia and uterine tenderness are signs of an intra-amniotic infection, with purulent cervical discharge being a late finding. Maternal WBC may be high but this is misleading.
Treat with IV antibiotics and prompt delivery, even if it means C-S.
How do patients describe PROM?
Diagnosing: Could be described as continuous small amounts or a gush of fluid that keeps going. Consider urinary incontinence, normal physiologic increases in vaginal secretions and increased cervical discharge from infection when this occurs.
What three tests do we do to figure out if PROM has occurred?
Discuss the nitrazine test
Nitrazine test: pH to determine ROM. Amniotic fluid is basic, vagina is acidic. Amnioin has pH > 7.1, vagina is 4.5 - 6.0. If the swab of fluid turns blue on pH paper, indicating a basic solution of 7.1 - 7.3, assume ROM, but cervical mucus, blood, and semen can give you false positives so be diligent on your swab specimen.
Discuss the Fern Test
Fern Test: distinguish amniotic fluid from everything else. Amniotic fluid will branch out while cervical mucus will be thicker with less branching. Let the specimen dry on a glass slide for 10 minutes without water or KOH, and then look. More reliable than Nitrazine.
Discuss how US can be used to detect PROM
US: If reduced fluid around baby, consider oligohydramnios vs. PROM. Infrequently performed but highly effective is ultrasound guided transabdominal instillation of indigo dye with observation of passage of dye into vagina.
Discuss the overall management of possible PROM (5 steps)
Palpate abdomen for fundal height and tenderness.
Do speculum exam to look for fluid and get specimens for gonorrhea, GBS, and chlamydia.
Obtain fluid from vaginal vault for FERN and Nitrazine.
Avoid digital examination until labor due to increased chance of infection.
Do US to check fetus presentation and amniotic fluid levels
How do we manage PROM that has occurred at term?
So after 37 weeks, 90% of ROM will lead to labor a little early. You can either wait the 12-24 hours for labor to start or you can induce it if there are risk factors.
Using oxytocin o get things started will decrease risk ofchorioamnionitis and endometritis, but expectant observation will decrease incidence of C-S, but don't sit on your ass for more than 24 hours.
Don't forget to give GBS prophylaxis if indicated right before delivery begins.
In preterm ROM, what is important in amniocentesis?
Pre-term ROM lab tests: Amniocentesis for Fetal lung maturity (FLM) is super important but in the setting of ROM and oligohydramnios, this can be difficult to interpret. Major thing to look for with amnio is infection, and again, if this is the case, labor and IV broad spectrum antibiotics are indicated.
Are tocolytics a sure thing for preterm ROM?
Use of tocolytics for antibiotics and steroid times of action has not been studied all that well, so it's difficult to say with confidence that tocolytics are important, but hey why not.