induction of labour and augmentation

Question 1

What is induction of labor and when is it indicated?

Answer 1

Induction of labor involves interventions to ripen the cervix and initiate labor. It is indicated for conditions such as post-term pregnancy, eclampsia, severe preeclampsia, PROM > 24 hours at term, PPROM > 34 weeks, and intrauterine fetal demise (IUFD).

Question 2

What are the contraindications for induction of labor?

Answer 2

Poor maternal condition requiring immediate delivery.
Abnormal lie and presentation (e.g., transverse lie).
Umbilical cord prolapse.
Obstructed labor.
Non-reassuring fetal status.
Placenta praevia.
Previous uterine surgery such as a transfundal cesarean.
Active genital herpes infection

Question 3

What methods are used to ripen the cervix before induction of labor if the Bishop score is < 6?

Answer 3

Misoprostol: 25 mcg PV every 4 hours, up to a maximum of 6 doses.
Foley catheter: Inflated with 40-60 ml of water.
Note: Misoprostol should not be used if the gestational age is ≥ 28 weeks in women with a previous cesarean delivery.

Question 4

What methods are used to induce labor when the cervix is favorable (Bishop score ≥ 6)?

Answer 4

Amniotomy (artificial rupture of membranes).
Oxytocin infusion: Starting at 7.5 dpm, titrated up to achieve 3 strong contractions every 10 minutes, with a maximum dose of 60 dpm.

Question 5

What are the considerations for inducing labor in women with a previous cesarean delivery?

Answer 5

Induction should only be started with the approval of a consultant.
Misoprostol should not be used if the gestational age is ≥ 28 weeks.
Consider amniotomy and Foley catheter induction with or without oxytocin.

Question 6

How is uterine tachysystole managed during labor induction?

Answer 6

Uterine tachysystole is defined as > 5 contractions in a 10-minute period.
Perform a non-stress test (NST) to assess fetal wellbeing.
Stop oxytocin if applicable.
Consider using a tocolytic, such as nifedipine, to reduce contractions.
Provide supportive care, such as positioning the mother in the left lateral position and administering IV fluids if needed.

Question 7

What is the Bishop score, and why is it used?

Answer 7

The Bishop score is a system used to assess the readiness of the cervix for labor. It helps predict the likelihood of a successful induction of labor by evaluating cervical dilation, effacement, consistency, position, and the station of the fetal head.

Question 8

What are the five components of the Bishop score?

Answer 8

Cervical dilation.
Cervical effacement.
Cervical consistency.
Cervical position.
Fetal station.

Question 9

What does a Bishop score indicate regarding the likelihood of a successful induction?

Answer 9

A score of 0-4: Low likelihood of successful induction; consider cervical ripening.
A score of 5-6: Moderate likelihood of successful induction.
A score of ≥ 7: High likelihood of successful induction.

Question 10

What are the mechanical methods of inducing labour?

Answer 10

balloon catheter
hygroscopic dilators
amniotomy
membrane sweep
and the MOA is release of prostaglandins from decidua & cervix & adjacent membrane

Question 11

What is the MOA of Misoprostol ?

Answer 11

it is a synthetic prostaglandin E1 analog
has uterotonic effects
binds to smooth muscles in the uterine lining

Question 12

What is augmentation of labor, and when is it indicated?

Answer 12

Augmentation of labor involves interventions to stimulate contractions and accelerate labor. It is indicated in cases of prolonged labor or arrest disorders, where labor progress is slower than expected.

Question 13

What are the contraindications for augmentation of labor?

Answer 13

Abnormal lie or presentation (e.g., transverse lie).
Obstructed labor.
Features suggestive of fetal compromise (e.g., fetal distress, IUGR).
Previous cesarean section or uterine surgery.
Any other contraindications to vaginal delivery (e.g., placenta praevia)

Question 14

What are the initial steps in managing a patient requiring augmentation of labor?

Answer 14

Confirm and document fetal wellbeing, presentation, uterine activity, and estimated fetal weight (EFW).
Perform a cervical exam to assess dilation, effacement, and station.

Question 15

What methods are used for the augmentation of labor in women with no previous uterine surgery?

Answer 15

Amniotomy: Artificial rupture of membranes.
Oxytocin infusion: Start with 2.5 IU in 1 L of normal saline or Ringer’s lactate. Begin at 7.5 dpm and increase by 15 dpm every 30 minutes until there are 3 strong contractions every 10 minutes. Maximum dose is 60 dpm.

Question 16

How is augmentation of labor managed in grandmultiparous women (P5 and above)?

Answer 16

Amniotomy is the preferred initial method.
Oxytocin should be used with caution and only with consultant approval due to the increased risk of uterine rupture

Question 17

hat considerations should be taken into account when augmenting labor in HIV-infected patients?

Answer 17

The management of augmentation does not differ significantly from non-HIV-infected patients.
Delay amniotomy to reduce the risk of vertical transmission

Question 18

What should be done if labor does not progress satisfactorily after 4 hours of strong contractions following augmentation?

Answer 18

Reassess cervical dilation.
If no progress, consider performing a cesarean delivery.
If the patient is awaiting cesarean delivery and there are no signs of fetal distress, oxytocin infusion may be continued while preparing for surgery

Question 19

What is the half-life of oxytocin, and why is this important for its administration during labor?

Answer 19

Oxytocin has a short half-life of approximately 3-5 minutes, which allows for precise control of uterine contractions during labor when administered intravenously.

Question 20

How does the mechanism of action of oxytocin ensure a coordinated contraction of the uterus?

Answer 20

The increase in intracellular calcium in response to oxytocin binding causes synchronized contractions of the myometrial cells, ensuring that the contractions are strong and effective, which is necessary for progressing labor.

Question 21

What are the effects of oxytocin on the cervix during labor?

Answer 21

Oxytocin indirectly contributes to cervical ripening by enhancing the release of prostaglandins, which soften and thin the cervix, facilitating its dilation during labor.

Question 22

How does oxytocin contribute to the process of labor beyond stimulating contractions?

Answer 22

Besides stimulating uterine contractions, oxytocin also promotes the release of prostaglandins from the uterine lining, which further enhance uterine contractions and help in the ripening of the cervix.

Question 23

What is the role of calcium in the action of oxytocin on uterine contractions?

Answer 23

The binding of oxytocin to its receptor increases the influx of calcium ions into the myometrial cells, and the release of calcium from the sarcoplasmic reticulum. The increased calcium levels activate the contractile proteins, leading to uterine contractions.

Question 24

How does oxytocin stimulate uterine contractions?

Answer 24

Oxytocin binds to oxytocin receptors on the myometrial cells of the uterus, triggering a cascade of intracellular events that increase intracellular calcium levels, leading to muscle contraction

Question 25

What is oxytocin, and what role does it play in labor?

Answer 25

Oxytocin is a peptide hormone produced by the hypothalamus and released by the posterior pituitary gland. It plays a critical role in labor by stimulating uterine contractions necessary for childbirth.