Medical Archive

Introduction

Labor induction

Indications

Ix: ROM + chorioamnionitis, Severe preeclampsia
CIx: Prior uterine incision, infection, CPD, previa

Techniques

Risks

• Chorioamnionitis, C/S ?, Uterine atony
  Uterine tachysystole
  • 10? ? >5?
  • Uterine contractions temporarily interrupt intervillous blood flow; excessively frequent contractions may cause fetal compromise as a result of decreased uteroplacental blood flow during contractions and inadequate recovery time.
• Uterine hypertonus
  • ? ? ?? ?2?
• Uterine hyperstiumulation
  • ??? 10?? 5? ?? ?? ? ?? ??? 2? ?? ??
  • ?? ????? ??, hyperstimulation? ???? ?? ?? IV hydration, O2 mak, Lt decubitus position? ?? fetal apsphyxia? ??.

Elective labor induction

Factors affecting induction success

Preinduction cervical ripening

Bishop score? ?? ??? (<4) ?? ?? ? cervical ripening ??

Score	Dilatation (cm)	Ewacement (%)	Station (–3 to +2)	Consistency	Position
0	Closed	0–30	–3	Firm	Posterior
1	1–2	40–50	–2	Medium	Midposition
2	3–4	60–70	–1	Sox	Anterior
3	?5	?80	+1, +2	—	—

Methods of induction and augmentation

PGE2 (Dinoprostone)	Bishop score ??, ?? ??? ?? ??
PGE1 (Misoprostone)	??? ?????? ?????. ??? ?? ?? ?? Not approved, but ACOG? ??
Oxytocin	????? ?? FHR, ?? ?? ??
Membrane stripping	????? ????? ?? ? PG ?? ??
Amniotomy	?? ?????. ??? ???? ?? ?? ???. ?? ??? ?? ?? ?? ??? ??? ????.

Prostaglandin E1

Oxytocin

IV oxytocin administration

Oxytocin dosage
Oxytocin regimen
Interval between incremental dosing
Maximal oxytocin dosage

Risks versus benefits

• Uterine tachysystole ? discontinuation until the excessive uterine activity and resulting fetal decelerations resolve.

Uterine contraction pressure

Active-phase arrest

Amniotomy for induction and augmentation

Amniotomy at approximately 5-cm dilation accelerated spontaneous labor by 1 to 1½ hours.