uworld vs MTB on Arrest of labor

[cyanide12345678]

So Question 551152 on uworld talks about arrest of active stage of stage 1 of labor. There has been no cervical dilation for 3 hours. Apparently uworld says that you don't do a C-section until 4 hours have elapsed. That sounded like a lot for arrest of labor. Infact, they are defining as the latent stage of first stage of labor until 6 cm cervical dilation. Did everything recently change in OBGYN??? Because those were definitely not the guidelines when I was rotating in OBgyn in December.

I looked up MTB (latest version just released). It says 2 hrs is when you call it Arrest of labor (and likely go ahead with a c-section after that). Which is right? Sorry I don't have access to uptodate right now and online websites have different numbers everywhere -_-

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[Phloston]

So Question 551152 on uworld talks about arrest of active stage of stage 1 of labor. There has been no cervical dilation for 3 hours. Apparently uworld says that you don't do a C-section until 4 hours have elapsed. That sounded like a lot for arrest of labor. Infact, they are defining as the latent stage of first stage of labor until 6 cm cervical dilation. Did everything recently change in OBGYN??? Because those were definitely not the guidelines when I was rotating in OBgyn in December.

I looked up MTB (latest version just released). It says 2 hrs is when you call it Arrest of labor (and likely go ahead with a c-section after that). Which is right? Sorry I don't have access to uptodate right now and online websites have different numbers everywhere -_-

From UpToDate:

"
SUMMARY AND RECOMMENDATIONS

●The Friedman curve (figure 1) and the norms established from Friedman’s data had historically been widely accepted as the standard for assessment of normal labor progression. Multiple studies have established that contemporary norms are different from those cited by Friedman. (See 'Friedman (historic) data' above.)

●Contemporary studies do not show an abrupt change in the rate of cervical dilation indicating a clear transition from latent to active labor; many women do not dilate at a rate of >1 cm/hour until 6 cm dilation. (See 'First stage' above.)

●The following table (table 1) is a reasonable guide for determining when the progress of labor is protracted and can be used with a partogram (figure 5). These data show that labor may take more than six hours to progress from 4 to 5 cm and more than three hours to progress from 5 to 6 cm, regardless of parity. (See 'First stage' above.

●Arrest of labor in the first stage is diagnosed at cervical dilation ≥6 cm dilation in a patient with ruptured membranes and no cervical change for ≥4 hours despite adequate contractions or no cervical change for ≥6 hours with inadequate contractions. (See 'Arrest' above.)

●For women with poor labor progression after reaching 6 cm dilation, we recommend administering oxytocin (Grade 1B) and monitoring another four hours with adequate uterine contractions (>200 Montevideo units), or six hours if unable to achieve this contraction pattern, before resorting to operative delivery. (See 'Oxytocin augmentation' above.)

●Arrest of the second stage of labor is defined as no progress (descent, rotation) after ≥4 hours for nulliparous women with epidural anesthesia (≥3 hours without epidural anesthesia) and after ≥3 hours for multiparous women with epidural anesthesia (≥2 hours without epidural anesthesia). Intervention is not indicated as long as labor appears to be progressing and the fetal heart rate pattern is reassuring. (See 'Second stage' above and 'Second stage' above.)"

 

[cyanide12345678]

From UpToDate:

"
SUMMARY AND RECOMMENDATIONS

●The Friedman curve (figure 1) and the norms established from Friedman’s data had historically been widely accepted as the standard for assessment of normal labor progression. Multiple studies have established that contemporary norms are different from those cited by Friedman. (See 'Friedman (historic) data' above.)

●Contemporary studies do not show an abrupt change in the rate of cervical dilation indicating a clear transition from latent to active labor; many women do not dilate at a rate of >1 cm/hour until 6 cm dilation. (See 'First stage' above.)

●The following table (table 1) is a reasonable guide for determining when the progress of labor is protracted and can be used with a partogram (figure 5). These data show that labor may take more than six hours to progress from 4 to 5 cm and more than three hours to progress from 5 to 6 cm, regardless of parity. (See 'First stage' above.

●Arrest of labor in the first stage is diagnosed at cervical dilation ≥6 cm dilation in a patient with ruptured membranes and no cervical change for ≥4 hours despite adequate contractions or no cervical change for ≥6 hours with inadequate contractions. (See 'Arrest' above.)

●For women with poor labor progression after reaching 6 cm dilation, we recommend administering oxytocin (Grade 1B) and monitoring another four hours with adequate uterine contractions (>200 Montevideo units), or six hours if unable to achieve this contraction pattern, before resorting to operative delivery. (See 'Oxytocin augmentation' above.)

●Arrest of the second stage of labor is defined as no progress (descent, rotation) after ≥4 hours for nulliparous women with epidural anesthesia (≥3 hours without epidural anesthesia) and after ≥3 hours for multiparous women with epidural anesthesia (≥2 hours without epidural anesthesia). Intervention is not indicated as long as labor appears to be progressing and the fetal heart rate pattern is reassuring. (See 'Second stage' above and 'Second stage' above.)"

The great Phloston replied to a post of mine 😛 Dude your posts on book reviews were extremely helpful before I started step studying. And some of your review slides were absolutely incredible. I just want to thank you for all the time you've put into helping others on this forum.

 

[Keto]

Hi

You're talking about stage 1 labor here, which is subdivided in two phases:

1. stage 1 latent phase
2. stage 1 active phase

• Stage 1 latent phase ("Effacement") starts with the onset of regular uterine contractions and ends with acceleration of cervical dilation. In this stage, the effacement of the cervix occurs.
  (<20h in primipara and <14h in multipara) {medscape}
• Stage 1 active phase ("Dilation") starts with acceleration of cervical dilation and ends with complete dilation.
  (>= 1.2 cm/h primipara, >= 1.5 cm/h multipara) {medscape}

There were some changes in the last 5-10 years on the definition, where the latent phase transits to the active phase. This medscape article highlights this well.

You see, how the classic (blue, Friedman) curve becomes steep after 4 cm of cervical dilation. This was the rationale, why the historic cut off for the latent phase transition was at 4cm. Recent studies (green, Vahratian) show a more gradual curve, that's why the "new" latent phase transition is now set around 6 cm (as mentioned by UpToDate and Phloston).

In order to answer your question, where to go to c-section, they need to know some numbers.

Some examples:

• 3 cm dilation, 3 hrs no change → give her time, she's probably at still at the latent phase.
• 7 cm dilation, 3 hrs no change → Assess uterine contraction quality (if good contractions = baby cannot pass → c-section)
• 7 cm dilation, 3 hrs no change → Assess uterine contraction quality (if not good contractions = give IV oxytocin, perform artificial rupture of the membranes → re-evaluate)

Have a great day!

BTW I cannot look at the UW question - the QId is usually 5 digits long.

 

[cyanide12345678]

Hi

You're talking about stage 1 labor here, which is subdivided in two phases:

1. stage 1 latent phase
2. stage 1 active phase

• Stage 1 latent phase ("Effacement") starts with the onset of regular uterine contractions and ends with acceleration of cervical dilation. In this stage, the effacement of the cervix occurs.
  (<20h in primipara and <14h in multipara) {medscape}
• Stage 1 active phase ("Dilation") starts with acceleration of cervical dilation and ends with complete dilation.
  (>= 1.2 cm/h primipara, >= 1.5 cm/h multipara) {medscape}

There were some changes in the last 5-10 years on the definition, where the latent phase transits to the active phase. This medscape article highlights this well.

You see, how the classic (blue, Friedman) curve becomes steep after 4 cm of cervical dilation. This was the rationale, why the historic cut off for the latent phase transition was at 4cm. Recent studies (green, Vahratian) show a more gradual curve, that's why the "new" latent phase transition is now set around 6 cm (as mentioned by UpToDate and Phloston).

In order to answer your question, where to go to c-section, they need to know some numbers.

Some examples:

• 3 cm dilation, 3 hrs no change → give her time, she's probably at still at the latent phase.
• 7 cm dilation, 3 hrs no change → Assess uterine contraction quality (if good contractions = baby cannot pass → c-section)
• 7 cm dilation, 3 hrs no change → Assess uterine contraction quality (if not good contractions = give IV oxytocin, perform artificial rupture of the membranes → re-evaluate)

Have a great day!

BTW I cannot look at the UW question - the QId is usually 5 digits long.

I love the explanation you've given. Thank you for taking the time out for that. Though try Qid 3116 (I just checked, this is the ID number for sure. If not, search for "protracted labor" and you'll get the question). The question has a lady at 8 cm dilation and no change for 3 hrs with good contractions, uworld says wait another hour. They are not calling it "arrest" of labor until 4 hours.

 

[Keto]

Oh wow, thanks cyanide! I checked it, and did not know that!

 

[VitaminD_1]

32 yo primigravida at term has a cervix 5 cm dilated x 4 hours despite oxytocin. contractions every 3 minutes and are 55 to 64 mm hg. exam shows molded vertex and caput succedaneum. diagnosis?
a. arrest of active phase
b. hypotonic contractions
c. protracted latent phase
d. normal active phase
e.normal second stage

i chose C as she is less than 6 cm dilated and thus in latent phase but my answer came back wrong... any ideas?