Prostaglandins, Leukotrienes and Platelet Activating Factor

Prostaglandins (PGs) are local hormones (autacoids) synthesized from

arachidonic acid

Prostaglandins highly effective in obstetrics

PGE₂ (Dinoprostone), PGE₁ (Misoprostol), and 15-methyl PGF₂α (Carboprost)

PGE2

Dinoprostone

PGE1

Misoprostol

15-methyl PGF₂α

Carboprost

Prostaglandins (PGs) are local hormones (autacoids) synthesized from arachidonic acid. PGE₂ (Dinoprostone), PGE₁ (Misoprostol), and 15-methyl PGF₂α (Carboprost) are highly effective in obstetrics because they

cause structural ripening of the cervix and direct myometrial contraction at any stage of pregnancy

Therapeutic Uses in Pregnancy & Labor

Cervical Ripening & Induction of Labor (IOL)

Postpartum Hemorrhage (PPH) Management

Medical Termination of Pregnancy (MTP)

Cervical Ripening & Induction of Labor (IOL)

• Dinoprostone (PGE₂): Administered as a 0.5 mg endocervical gel or 10mg vaginal insert. It breaks down collagen networks to soften and dilate an unfavorable cervix while inducing coordinated contractions.

• Misoprostol (PGE₁): Administered as a 25mcg vaginal or oral tablet every 4–6 hours. Cheap, stable at room temperature, and highly effective.

Postpartum Hemorrhage (PPH) Management

• Carboprost (15-methyl PGF₂α): Administered as 250micro gram IM. It is the drug of choice for refractory PPH caused by uterine atony when Oxytocin and Ergometrine fail.

• Misoprostol (PGE₁): Administered as 600-800mcg rectally, sublingually, or orally. Highly useful in low-resource settings to prevent or treat atonic PPH.

Medical Termination of Pregnancy (MTP)

• First Trimester (< 7 weeks): Mifepristone (200mg oral) followed 48 hours later by Misoprostol (400mcg oral/vaginal).

• Mid-Trimester Abortion & IUFD: Repeated higher doses of Misoprostol to empty the uterus.

Adverse Effects

• Uterine Tachysystole: Hyperstimulation can lead to fetal distress.

• Systemic Effects: Diarrhea, vomiting, nausea (due to smooth muscle stimulation).

• Pyrexia: Transient shivering and fever (classic side effect of high-dose Misoprostol).

• Bronchospasm: Carboprost stimulates bronchial smooth muscle.

Contraindications

• Previous Cesarean Scar / Myomectomy: Absolute Contraindication due to high risk of scar dehiscence and uterine rupture.

• Asthma: Contraindicated for Carboprost (PGF₂α).

• Cephalopelvic Disproportion (CPD) & Malpresentations.

Prostaglandins four therapeutic uses

1. Cervical Ripening and Induction of Labor

2. Treatment of Refractory Postpartum Hemorrhage (PPH)

3. Medical Termination of Pregnancy (MTP) – First Trimester

4. Mid-Trimester Abortion & Management of Intrauterine Fetal Death (IUFD)