Stages of Labor

00:01 Now as part of normal labor, let's just discuss the stages of labor.

00:06 Stage 1.

00:08 This is the onset of labor until 10 centimeters dilated.

00:12 During stage 1 contractions cause the cervix to change and it causes the fetus to descent into the pelvis.

00:19 Phase 1 can be divided into two phases, the latent phase which is the onset of contractions until 4 centimeters, and the active phase.

00:28 This is from 6 centimeters to 10 centimeters dilated.

00:32 Now when we speak of cervical change, we're talking about cervical dilation, effacement and station.

00:39 Dilation refers to how open the external os of the cervix is.

00:44 This is measured in centimeters and we do this with a digital exam.

00:48 And you can see here from the example, as we go from 1 centimeters to 2 centimeters to 3 centimeters, the external os is opening more.

00:55 When we talk about effacement we talk about how thick the cervix is.

01:01 So when a woman that's not pregnant her cervix feels kind like the tip of your nose.

01:06 It's pretty thick.

01:08 As labor progresses, the cervix starts to thin out and it starts to shorten.

01:13 Now in a primigravida woman, the cervix will thin out more than it dilates.

01:18 The multiparous is the opposite.

01:20 The cervix will usually open a little bit and then starts to thin out.

01:24 And then you see here at 10 centimeters the cervix is fully fully thinned out.

01:29 We call that a 100% effaced.

01:31 Now when we say station, that means we're referring to the presenting part and relationship to ischial spines of the mom.

01:42 You can see at the ischial spines we call that 0 station.

01:47 1 centimeter above is -1 station.

01:49 2 centimeters above is -2.

01:52 On the flip side, 1 centimeter down is +1 station.

01:56 2 centimeters down is +2 station.

01:58 Now we have some parameters that we consider to be normal for the first stage of labor.

02:05 For primiparous woman in latent labor, we expect that to last under 20 hours.

02:11 For a multiparous we expected it to last under 14 hours.

02:14 Now for that active phase of labor for the primiparous woman, we expect her cervix attain 1.2 centimeters per hour.

02:21 And then for the multiparous 1.5 centimeters per hour is the norm.

02:27 Now moving on to stage 2.

02:29 Stage 2 of labor is from 10 centimeters dilated until the delivery of the infant.

02:35 During stage 2, the fetus is entering the pelvis through the cardinal movements of labor which begin in Stage 1 and completed in Stage 2.

02:44 So let's go to cardinal movements of labor.

02:47 First we have engagement.

02:49 This is when the head is starting to come into the pelvis.

02:53 Then we have descent as the head goes down through the pelvis.

02:55 Then we have flexion.

02:58 And basically, that's when the chin is tucked into the chest.

03:01 Internal rotation as the head starts to turn.

03:04 Then we have extension as the head comes underneath the pubic symphysis.

03:09 External rotation, the head is going to return to the same plain that it was in prior to internal rotation.

03:15 And then we have expulsion which is delivery of the fetus.

03:18 Now if you are having a little trouble remembering these steps, I have a little-- let's say metaphor to help you remember.

03:24 We can think it like a wedding.

03:27 First you get engaged.

03:29 Then you descend down the aisle.

03:31 Then you flex your head to pray.

03:33 Then you internally rotate as you turn to your new spouse.

03:36 Then you extend as you lift your head up to further kiss.

03:39 Then you have external rotation as you turn back towards the congregation.

03:43 And then expulsion as you walk down the aisle.

03:46 I hope that little tip, it helps you remember these movements.

03:50 Now for Stage 2, let's consider our norm.

03:53 So for primiparous with an epidural 3 hours.

03:57 A multiparous with an epidural 2 hours.

04:00 Primiparous without an epidural 2 hours.

04:03 And a multiparous without an epidural 1 hour.

04:06 So these are our norms that we expect for how long it takes for mom pushing in Stage 2 of labor.

04:13 Now Stage 3 of labor.

04:15 This is from the delivery of the infant until delivery of the placenta.

04:18 To deliver the placenta, we have gentle downward tractional umbilical cord, while the other hand puts gentle traction on the uterus.

04:27 In the normal setting we expect the placenta to deliver within 30 minutes.