Your Water Breaks First - A Date to PROM (Premature Rupture of Membranes) - Secondary Analysis of the Trial Data

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While the original report from the TERM PROM study showed no differences in neonatal infection rates over all, secondary analysis makes it clear that length of time between rupture and delivery matter, and that there are modifiable factors, meaning that the risk is less when a woman and her baby receive optimal care.

Secondary analysis of the data showed that the over all rate of chorioamnionitis (6.7%), while high,  was confounded by the fact that few women in the study had antibiotics for GBS, which is a known risk factor.

The Centers for Disease Control (2010) guidelines for management of GBS+ women say nothing about inducing woman with ruptured membranes at term, which suggests that awaiting spontaneous labor is acceptable provided that antibiotic therapy is initiated.

It seems common sense would dictate that women wait for the first round of antibiotics to be fully administered before making any decisions and even those who prefer not to wait for labor to begin on its own should delay induction until they have the initial round of antibiotics on board.

In any case, regardless of GBS status or decisions around whether or when to induce, to minimize the risk of infection, women should avoid digital exams until labor is well established and their use should be kept at the very minimum during labor.

It is very important to remember that most of the studies as of the 2017 Cochrane review did not take into account the number of digital vaginal exams, nor did they follow current GBS infection protocols.

The number of digital vaginal exams after rupture is probably the most important predictor of whether a woman with term PROM will be clinically diagnosed with chorioamnionitis during these studies. For example 56% of the women in the waiting groups had four or more exams versus 49% of the women in the immediate induction groups who had four or more exams.

Secondary analysis of the term PROM study clearly showed that a person’s risk of being diagnosed with chorioamnionitis increased as the number of vaginal exams they received increased. For example, a study done in 2004 (Ezra et. al.) found that seven or more vaginal exams were an important risk factor for infection. This number of exams increases a woman’s odds of being diagnosed with chorioamnionitis five fold.

The reason vaginal exams can lead to infection is the fact that even with the use of sterile gloves the care provider is potentially introducing bacteria from outside of the vagina and/or preexisting vaginal flora up to the cervix as they conduct the exam.  As previously noted this is termed as an ascending infection and is a primary cause of intrapartum infections.

You want to reduce your risk of acquiring an infection after your water breaks, stay out the hospital, and failing that politely but firmly say NO to digital vaginal exams and other invasive procedures.

The study data also suggests that intravenous oxytocin (Pitocin) is the induction agent of choice. It appears to reduce maternal chorioamnionitis rates compared to other methods of induction (4% intravenous oxytocin versus 6.2% prostaglandin gel).

The studies further showed that while there was no significant difference between immediate induction with prostaglandin gel or the expectant management group who waited up to four days before being induced via prostaglandin gel there was a significant difference in the oxytocin groups. (4% immediate/oxytocin versus 8.6% waiting/oxytocin) in regards to the rate of chorioamnionitis.

The secondary analysis of this data shows that there exist other factors than immediate induction that could provide reasons for this lower number.

Women in the immediate induction with intravenous oxytocin group

  • had fewer vaginal exams overall
  • had shorter labors
  • spent less time in the hospital compared to women who waited.

In other words, it is not necessarily immediate induction that decreases the risk of chorioamnionitis it is the fact that during the course of “waiting it out” women were subjected to many more digital vaginal exams and due to location more exposure to potential infection.

Furthermore, given the intensity of contractions during a Pitocin induction, of course labor and hospital stays were both of shorter duration.

Induction with prostaglandin gel is a common risk factor for intrapartum fever and furthermore is implanted up into the vagina via an invasive procedure, so it makes sense that it would show higher chorioamnionitis rates overall.  Especially considering the studies allowed that the existence of a maternal fever alone was enough to justify a clinical diagnosis of chorioamnionitis. 

Mayri S. Leslie posted an article to Science & Sensibility in 2009 in an effort to bring these issues into perspective, encouraging us to think about what we now know and how judicious care providers work with women today if their waters break before labor at term.

  1. Unless a woman declines, she is screened for GBS before term, so if her water breaks we can factor in whether she is positive or negative into our recommendation of whether she may be at less risk opting for induction or waiting.
  2. As indicated by the guidelines from the Center for Disease Control (CDC 2010) we treat women who are GBS+ with antibiotics prophylactically to reduce the risk of infection for her and her baby.
  3. For women who decline screening or whose GBS status is unknown we follow guidelines from the CDC which suggest we treat according to other risk factors such as length of time the membranes are ruptured, signs of infection in the mother and baby etc.
  4. In either case, we know NOT to do any vaginal exams until we know mom is in active labor and even then to minimize and avoid them until absolutely necessary because vaginal exams themselves are one of the highest risk factors for increasing infections once the water bag is ruptured.

“While inductions, like all medical interventions have their place and time when indicated—they cannot be justified as a standard procedure for a normal physiological occurrence in a healthy full term pregnancy.” Mayri S. Leslie

Personally—as always— I will continue to promote normal healthy physiological birth and a woman’s right to make her own decisions during her pregnancy.

Women who experience PROM should be properly counseled by their doctor/midwife about the potential benefits and harms of both induction and waiting for labor to begin, so that they can base their decisions on what is best for their unique situation, taking into account personal values, preferences, and GBS status.