Induction of Labor

Induction of Labor

Click Here to Listen to the Podcast on Soundcloud
Click Here to Download the Podcast's Audio File
Click Here to Download the Outline File 

IOL Criteria:

-Indications:

*Pregnancy: Placental abruption, Chorio, PreE, PROM, Postterm *Maternal: gHTN/cHTN, gDM, pulm/cardiac disease, APAS

*Fetal compromise: IUFD, IUGR, isoimmunization, oligo

            -Contraindications:

                        *Pregnancy: Placenta previa, vasa previa, cord prolapse

*Maternal: Previous classical c-section, HSV lesions, h/o myomectomy entering endometrial cavity

                        *Fetal: Transverse lie

“Two-Stage Induction”: A slang phrase heard on L&D which refers to a patient whose labor induction requires two phases – a cervical ripening and a cervical dilatory phase.

Cervical Ripening:

            -Facilitate cervical softening, thinning, and dilating (makes it ‘favorable’)

            -Reduced failed induction rate, reduced induction to delivery time

            -Methods:

*Prostaglandins (Misoprostol tab 25mcg intravaginally or sublingual)

-Dinoprostone insert or gel – the gel releases prostaglandin more rapidly

-Sublingual is less effective, but has less complications

-Higher doses may be a/w fever, N/V/D

*Mechanical (Foley Balloon)

            -Risks VB, displacement of presenting part

            -Inadequate data to support outpatient use

*Osmotic (Laminaria japonicum)

-Risks of increased peripartum infections

Labor Induction:

            -Begin uterine contraction, cause fetus to descend

            -Methods:

*Oxytocin/Pitocin

                                    -Uterine response is related to GA

-Success associated with : decreased BMI, favorable cervix, increasing GA, greater parity

                                    -Hyponatremia

                        *Amniotomy (AROM)

                                    -If used alone, may result in delay onset of ctx’s

                                    -Unclear data on timing if GBS+

-Risk of cord prolapse/compression, chorio, rupture of vasa previa

-Contraindicated in HIV+, as time of ROM is an independent RF for vertical transmission

Outpatient Labor Initiation:

                        *Membrane Stripping

                                    -Increases likelihood of labor in next 48hrs

                                    -Risk of PROM, VB, pain; unclear data if GBS+

                        *Nipple Stimulation

                                    -Helpful if woman already has favorable cervix over 72hrs

                                    -A/w decreased risk of PPH

-In a systematic review, a/w increased trend in perinatal death; not recommended in unmonitored setting

                        *Walking

                                    -Not helpful

Def’ns:

Tachysystole: >5ctx/10min, avg over 30min

            -Always described with presence or absence of FHR decels

*Management of decels – maternal repositioning, oxygen, reducing dosing of induction agents (decreased pitocin rate, remove vaginal PG tab). Terbutaline or other tocolytics may be administered

-Can result in placental abruption, uterine rupture and fetal strip complications/hypoxia

Active Labor: >6cm dilation with contractions that are changing the cervix

Prolonged Latent Phase: 20hrs nullip, 14hrs multip

-Failed Induction of Labor – an Induction of Labor that was unable to get to the second stage (pushing)

Labor Arrest

            -First Stage (Cervical Dilation): 

-No cx change >4h w/ adequate ctx; >6h w/out adequate ctx

            -Adequate Ctx defined as Montevideo Units (MVU) >200

                        -Measured using IUPC, measuring 10min of ctx

-Calculate by subtracting baseline uterine tone from peak of ctx

            -Second Stage (Pushing):

                        -Prolonged

                                    -Nulliparous:  >3h w/ epidural, >2h w/out

                                    -Multiparous: >2h w/ epidural, >1h w/out

                        -Arrest

                                    -Nulliparous:  >4h w/ epidural, >3h w/out

                                    -Multiparous: >3h w/ epidural, >2h w/out

PROM patients:

-IOL decreases time to delivery as well as rate of chorio, PP fevers, neonatal abx use; without an increase in c-section rate

IUFD:

            -Timing of delivery is not urgent

-Coagulopathies a/w prolonged fetal retention uncommon

            -2^nd Trimester: D&E

                        -Limits ability to perform macroscopic autopsy

            -Later GA: May require IOL

                        - Miso 400mcg q6h intravaginal, Pitocin, Foley catheter

                        -C-section only for unusual circumstances











Cervical Dilation and Effacement. Image from Anniebyrd.blogspot.com