Preterm Labor: Causes, Diagnosis, Prevention and Management
Below is a **single-place, SEO-optimized, exam-ready and clinically complete reference** on **Preterm Labor**, written with clear **H1–H4 structure**, high-value keywords, and authoritative medical depth.
---
# **Preterm Labor: Causes, Diagnosis, Prevention and Management**
## **Definition of Preterm Labor**
Preterm labor is defined as **regular uterine contractions associated with cervical changes occurring between 20 weeks and before 37 completed weeks of gestation**, leading to preterm birth if not arrested.
---
## **Epidemiology and Importance**
* Accounts for **10–12% of all pregnancies globally**
* Major cause of **neonatal morbidity and mortality**
* Responsible for complications such as **respiratory distress syndrome, intraventricular hemorrhage, necrotizing enterocolitis, sepsis, and long-term neurodevelopmental disability**
---
## **Pathophysiology of Preterm Labor**
Preterm labor results from **premature activation of the normal labor pathway**, involving:
### **1. Uterine Activation**
* Increased **oxytocin receptors**
* Enhanced **prostaglandin synthesis**
### **2. Cervical Ripening**
* Collagen degradation
* Increased inflammatory mediators
### **3. Decidual and Membrane Activation**
* Infection or inflammation leads to cytokine release
* Prostaglandins stimulate uterine contractions
---
## **Etiology and Risk Factors**
### **Maternal Factors**
* Previous preterm birth
* Short interpregnancy interval
* Extremes of maternal age
* Smoking, substance abuse
* Poor antenatal care
* Low socioeconomic status
### **Obstetric Factors**
* Multiple pregnancy
* Polyhydramnios
* Placental abruption
* Placenta previa
* Uterine anomalies
### **Infective Causes**
* Urinary tract infection
* Bacterial vaginosis
* Chorioamnionitis
### **Fetal Factors**
* Congenital anomalies
* Fetal distress
---
## **Clinical Features of Preterm Labor**
### **Symptoms**
* Regular uterine contractions (≥4 in 20 minutes or ≥8 in 60 minutes)
* Lower abdominal or back pain
* Pelvic pressure
* Increased vaginal discharge
* Vaginal spotting or bleeding
### **Signs**
* Cervical dilation ≥1 cm
* Cervical effacement ≥80%
* Shortened cervical length on ultrasound
---
## **Diagnosis of Preterm Labor**
### **Clinical Assessment**
* History of contractions and risk factors
* Sterile speculum examination
### **Investigations**
#### **1. Transvaginal Ultrasound**
* Cervical length <25 mm before 24 weeks suggests high risk
#### **2. Fetal Fibronectin Test**
* Positive test indicates increased risk of preterm birth within 7–14 days
#### **3. Laboratory Tests**
* Urine analysis and culture
* High vaginal swab if infection suspected
* Complete blood count and CRP when indicated
---
## **Differential Diagnosis**
* Braxton Hicks contractions
* Urinary tract infection
* Abruptio placentae
* Placenta previa
* Gastrointestinal causes
---
## **Management of Preterm Labor**
### **General Principles**
* Confirm diagnosis
* Exclude contraindications to tocolysis
* Assess gestational age and fetal wellbeing
---
### **Tocolytic Therapy**
Used to **delay delivery for 48 hours** to allow steroid administration.
#### **1. Nifedipine (First Line)**
* **Indication:** Suppression of uterine contractions
* **Mechanism:** Calcium channel blockade
* **Dose:** 20–30 mg orally loading, then 10–20 mg every 6–8 hours
* **Adverse Effects:** Hypotension, headache, flushing
* **Contraindications:** Hypotension, cardiac disease
* **Monitoring:** Blood pressure, pulse
* **Counselling:** Avoid sudden posture changes
#### **2. Atosiban**
* Oxytocin receptor antagonist
* Preferred in cardiac disease
#### **3. Indomethacin**
* Used before 32 weeks
* Risk of premature ductus arteriosus closure
---
### **Antenatal Corticosteroids**
Enhance fetal lung maturity.
#### **Betamethasone**
* **Dose:** 12 mg IM, two doses 24 hours apart
* **Benefits:** Reduces RDS, IVH, NEC, neonatal mortality
* **Monitoring:** Blood glucose in diabetics
---
### **Magnesium Sulfate for Neuroprotection**
* **Indication:** <32 weeks gestation
* **Benefit:** Reduces cerebral palsy risk
* **Adverse Effects:** Flushing, respiratory depression
* **Monitoring:** Reflexes, urine output, respiratory rate
---
### **Antibiotics**
* Not routinely indicated
* Used when infection is confirmed or suspected
---
## **Contraindications to Tocolysis**
* Intrauterine fetal demise
* Lethal fetal anomalies
* Severe preeclampsia or eclampsia
* Chorioamnionitis
* Significant vaginal bleeding
---
## **Prevention of Preterm Labor**
### **Primary Prevention**
* Smoking cessation
* Treatment of genital and urinary infections
* Adequate antenatal care
### **Secondary Prevention**
#### **Progesterone Therapy**
* **Indication:** Previous preterm birth or short cervix
* **Dose:** Vaginal progesterone 200 mg daily
* **Mechanism:** Maintains uterine quiescence
#### **Cervical Cerclage**
* Indicated in cervical insufficiency
* Performed between 12–14 weeks in selected cases
---
## **Complications**
### **Maternal**
* Operative delivery
* Infection
* Postpartum hemorrhage
### **Neonatal**
* Respiratory distress syndrome
* Sepsis
* Long-term neurodevelopmental impairment
---
## **Prognosis**
* Depends on **gestational age at delivery**
* Survival improves significantly after **32–34 weeks**
* Early recognition and management improve outcomes
---
## **Key Clinical Pearls**
* Cervical length is the **best predictor** of preterm birth
* Tocolytics delay labor but **do not prevent preterm birth**
* Corticosteroids are the **most effective intervention** for neonatal outcomes
* Magnesium sulfate provides **neuroprotection**, not tocolysis
---
## **SEO Keywords (Comma Separated)**
preterm labor, premature labor, causes of preterm labor, diagnosis of preterm labor, management of preterm labor, tocolytic therapy, antenatal corticosteroids, magnesium sulfate neuroprotection, cervical length ultrasound, fetal fibronectin test, prevention of preterm birth, progesterone therapy pregnancy
---
If you want, I can **next provide**:
* **25 hard case-based MCQs using HTML CSS JS (single file)**
* **FAQs for SEO rich results**
* **Schema-ready medical content**
* **Exam-oriented summary tables**
Just tell me 👍
