Induction of Labor

Question 1

Methods of labor induction

Answer 1

oxytocin, membrane stripping, amniotomy, nipple stimulation, prostaglandin E analogues

Question 2

Cervical remodeling changes

Answer 2

collagen breakdown and rearrangement, changes in glycosaminoglycans, increased production of cytokines, and white blood cel infiltration

Question 3

Bishop scoring system

Answer 3

Refer to album

Question 4

Unfavorable cervix

Answer 4

Bishop score of 6 or less

Question 5

Methods of cervical ripening

Answer 5

Mechanical dilation:

• hygroscopic dilators
• osmotic dilators (Laminaria japonicum)
• Foley catheters (14-26 F) with 30-80 mL inflation volumes
• double balloon devices
• extra-amniotic saline infusions with rates of 30-40 mL/hr

Non-mechanical:

• synthetic prostaglandin E1 (PGE1)
• prostaglandin E2 (PGE2)

Question 6

Complication of using Laminaria japonicum

Answer 6

possible increased infection rate

Question 7

Benefits of mechanical dilation

Answer 7

decreased C-section rate with all except extra-amniotic saline infusions when compared to oxytocin alone

Question 8

Advantage of Foley catheter over prostaglandins

Answer 8

low cost, stability at room temperature, reduced rate of uterine tahcysystole with or without FHR changes

Question 9

Misoprostol

Answer 9

PGE1 analogue, used for cervical ripening and IOL

Route: vaginally, orally, sublingually

Dose: 25 mcg?

Question 10

Dinoprostone

Answer 10

PGE2 analogue, used for cervical ripening

Route: gel (0.5 mg) and vaginal insert (10 mg)

• Increase the likelihood of delivery within 24 hrs, don’t reduce the chance of C section, and increase the risk of tachysystole and FHR changes

Question 11

Oxytocin

Answer 11

used for IOL

• Stimulates uterine contraction within 3-5 mins of use, steady level achieved in 40 minutes
• gradual increase in response from 20 - 30 weeks
• Maximum amount of receptors present by 34 weeks

Question 12

Predictors of successful response to oxytocin induction

Answer 12

• Lower BMI, greater cervical dilation, parity or gestational age

Question 13

Membrane stripping

Answer 13

Causes an increase in phospholipase A2 and PGF2alpha2
- Increases the likelihood of spontaneous labor within 48 hours

Side effects: discomfort, vaginal bleeding, and irregular contractions over the next 24 hrs

Question 14

Membrane stripping in group B + patients

Answer 14

ify

Question 15

Amniotomy

Answer 15

Typically used if the cervix is favorable

• When used alone, it can result in long periods before contractions start
• Unknown when the best timing is in patients being treated for group B strep

Question 16

Nipple stimulation

Answer 16

• Used in patients with favorable cervixes
• No difference in rates of meconium stained amniotic fluid or C section rates
• Decreased rates of postpartum hemorrhage
• Not encouraged in unmonitored setting

Question 17

Bishop score 0

Answer 17

closed, posterior, 0-30% effaced, -3 station, firm cervix

Question 18

Bishop score 1

Answer 18

1-2 cm dilated, midposition, 40-50% effaced, -2 station, medium cervix

Question 19

Bishop score 2

Answer 19

3-4 cm dilated, anterior, 60-70% effaced, -1,0 station, soft cervix

Question 20

Bishop score 3

Answer 20

5-6 cm dilated, anterior, 80% effaced, 1+, 2+ station, soft

Question 21

Normal contraction frequency

Answer 21

5 contractions or less in 10 mins, averaged over 30 mins

Question 22

Tachysystole

Answer 22

more than 5 contraction in 10 mins, averaged over 30 mins

- Always specify presence or absence of FHR changes

Question 23

Indications for IOL

Answer 23

placental abruption, chorioamnionitis, fetal demise, gestational HTN, preeclampsia, eclampsia, PROM, post-term pregnancy, maternal health problems, severe IUGR, isoimmunization, oligohydramnios

Question 24

Contraindications for IOL

Answer 24

vasa previa, active genital herpes, transvere lie, classical C section, umbilical prolapse, prior myomectomy into the endometrial cavity

Question 25

Confirmation of term gestation

Answer 25

- Ultrasound at 20 wks or less supports gestational age of 39 wks or greater - FH tones have been documented for at least 30 weeks by Doppler - 36 wks since a positive beta HCG

Question 26

IOL risk in nulliparous pts with unfavorable cervix

Answer 26

twofold increased risk of C section

Question 27

Failed induction time period

Answer 27

- Allow for at least 12-18 hours of latent labor before diagnosing failure

Question 28

What is the relative effectiveness of available methods for cervical ripening in reducing the duration of labor?

Answer 28

both Foley catheter placement and prostaglandin administration reduced length of labor and C section rates, but prostaglandins have an increased risk of tachnysystole

Question 29

Which is more effective misoprostol or dinoprostone

Answer 29

misoprostol

Question 30

Vaginal misoprostol

Answer 30

less use of epidural or analgesia, more vaginal deliveries within 24 hrs, and increased rates of tachysytole

Question 31

How should prostaglandins be administered?

Answer 31

Misoprostol: 25 mcg tablet, every 3-6 hrs with oxytocin administered not less than 4 hrs after, sometimes 50 mcg is acceptable Dinoprostone: 1.5 mg in the cervix, 2.5 mg in the vagina - repeat dose can be given 6-12 hrs later - oxytocin can be given 6-12 hrs later - No more than three doeses or 7.5 mg of the gel

Question 32

Highest risk of tachysystole

Answer 32

vaginal misoprostol

Question 33

Risks of vaginal misoprostol

Answer 33

tachysystole, category III FHR tracing, and uterine rupture in women with C sections

Question 34

How to correct uterine tachysytole

Answer 34

removal of medication, terbutaline

Question 35

Maternal side effects from PGE2

Answer 35

very rare diarrhea, fever, vomiting - Caution should be taken in women with glaucoma, severe renal or hepatic disease, and asthma (bronchodilator though so low risk)

Question 36

What are the recommended guidelines for fetal surveillance after prostaglandin use?

Answer 36

Patient should be recumbent for the first 30 mins - FHR and uterine activity should be monitored for the first 30 mins to 2 hrs after admin. - Peak contractions in the first 4 hrs

Question 37

Are cervical ripening methods appropriate in an outpatient setting?

Answer 37

yes, in selected patients (dioprostone and mechanical dilation)

Question 38

Complications of oxytocin

Answer 38

tachysystole, water intoxication | concentrated solutions can cause low BP

Question 39

Complications of amniotomy

Answer 39

fetal cord compression, and umbilical cord prolapse, chorioamnionitis - Get FHR before and after amniotomy

Question 40

Membrane stripping

Answer 40

vaginal bleeding from undiagnosed placenta previa, accidental amniotomy

Question 41

Oxytocin regimen - high dose versus low dose

Answer 41

trade off between shorter labor times, c section for dystocia, and chorio and tachysystole

Question 42

Low-dose oxytocin dosing

Answer 42

0.5-2 initial dose, 1-2 mU/min, dose interval 15-40 mins

Question 43

High-dose oxytocin dosing

Answer 43

6 initial dose, 3-6 mU/min, dose interval 15-40 mins

Question 44

Are there special considerations that apply for induction in a woman with ruptured membranes?

Answer 44

IOL should be started at presentation to decrease risk of chorio; vaginal misoprostol ok

Question 45

What methods can be used for IOL with IUFD in the late second, third trimester?

Answer 45

D&E in late second trimester, oxytocin, vaginal misoprostol (200-400 mcg every 4-12 hrs ) (most useful before 28 wks)