Preterm Labour: What It Is, Why It Happens, and How It Is Managed
A woman visiting a doctor for contractions before pregnancy.
Preterm birth — birth before 37 completed weeks of pregnancy — is responsible for the largest proportion of neonatal deaths and long-term disability in infants worldwide. In India, the preterm birth rate is approximately 13 to 14% — one of the highest in the world. Understanding the warning signs, who is at risk, and what treatment can do is important for every pregnant woman.
Dr. Shachi Singh, consultant obstetrician at Prakash Hospital, Sector 33, Noida, explains.
The Distinction: True Preterm Labour vs Braxton Hicks
Not all contractions before 37 weeks are preterm labour. Braxton Hicks contractions — practice contractions — are extremely common from the second trimester. The distinction matters because true preterm labour requires assessment and possibly treatment, while Braxton Hicks is normal.
Braxton Hicks contractions:
- Irregular — varying frequency and duration
- Usually painless or mildly uncomfortable
- Do not increase in intensity over time
- Typically ease with rest, position change, or hydration
- No cervical change
True preterm labour:
- Regular contractions — increasing in frequency (4 to 6 per hour), duration (lasting more than 30 seconds), and intensity
- Often painful
- Do not ease with rest or hydration
- Associated with cervical changes (effacement and dilation) — confirmed on examination
- May be accompanied by a show (pink or bloody mucus), rupture of membranes, or pelvic pressure
When to go in: Regular painful contractions before 37 weeks — do not wait. Get assessed.
Causes and Risk Factors
Preterm labour is not one condition — it has multiple causes:
Infection and inflammation: The most common identifiable cause. Ascending infection from the vagina/cervix (bacterial vaginosis, group B streptococcus, chlamydia, untreated UTI) triggers an inflammatory cascade that initiates contractions. Systemic infections — malaria, typhoid, severe UTI — cause preterm labour through systemic inflammatory mechanisms.
Uterine overdistension: Multiple pregnancy (twins, triplets), polyhydramnios (excess amniotic fluid) — the uterus reaches the "stretch threshold" for labour initiation earlier.
Cervical incompetence / short cervix: As discussed in the cervical cerclage blog — painless cervical opening in the mid-trimester. Cervical length below 25 mm between 16 and 24 weeks is a strong risk factor.
Placental problems: Placenta praevia, placental abruption.
Previous preterm birth: The strongest risk factor — a woman who has delivered preterm before has a 15 to 30% risk of preterm delivery in the next pregnancy.
Uterine anomalies: Septate uterus, bicornuate uterus.
Social and lifestyle factors: Smoking, substance use, very low socioeconomic status, poor nutrition.
Idiopathic: No identifiable cause — approximately 50% of preterm births.
Assessment When Preterm Labour Is Suspected
At Prakash Hospital, assessment includes:
Speculum examination: Looking for ruptured membranes (pooling of amniotic fluid), signs of infection, cervical dilation and effacement.
Transvaginal cervical length: A cervical length below 15 to 25 mm confirms a very high risk of delivery within 7 days.
Fetal fibronectin (fFN) test: A swab from the cervix detects fibronectin — a protein released when membranes begin to separate from the uterine wall. A negative fFN result very reliably predicts that delivery will not occur within 7 days — allowing treatment and transfer to be avoided if the result is negative.
CTG: Fetal wellbeing assessment.
Swabs: High vaginal swab, urine culture — to identify and treat any infection driving the contractions.
Treatment
Tocolysis (Stopping Contractions)
Tocolytic medications slow or stop contractions — buying time (48 to 72 hours) to administer corticosteroids and arrange transfer to a centre with neonatal intensive care capability if needed.
Nifedipine (calcium channel blocker): The most widely used first-line tocolytic in India. Oral tablet — easy to administer, generally well tolerated. Reduces contraction frequency.
Atosiban: An oxytocin receptor antagonist — the most specific tocolytic with the fewest side effects. Intravenous infusion.
Betamimetics (ritodrine, salbutamol): Older class — still used but more side effects.
Tocolysis is appropriate from 24 to 34 weeks (where time gained for steroids and transfer has the most benefit) and is not used after 34 weeks (the risk of prematurity is lower and the benefit of tocolysis minimal).
Corticosteroids (Lung Maturation)
Two injections of betamethasone or dexamethasone given 24 hours apart — one of the most powerful life-saving interventions in obstetric medicine. Corticosteroids accelerate fetal lung maturation and reduce respiratory distress syndrome, intraventricular haemorrhage, and necrotising enterocolitis in preterm babies.
Given to all women between 24 and 34 weeks in threatened preterm labour. The benefit is most marked between 24 and 34 weeks.
Magnesium Sulphate for Neuroprotection
Before 32 weeks (in some protocols up to 34 weeks), magnesium sulphate infusion is given to protect the fetal brain from damage — reducing the risk of cerebral palsy in very preterm babies.
Antibiotics
If membranes have ruptured (PPROM — preterm premature rupture of membranes), prophylactic antibiotics (erythromycin-based protocol) reduce the risk of infection and prolong the time from membrane rupture to delivery. If GBS colonisation is identified, antibiotics are given in labour to prevent neonatal GBS infection.
If Preterm Birth Happens
A baby born at 32 to 36 weeks (late preterm) typically requires NICU support (temperature, feeding, respiratory) but has very good outcomes with appropriate care. Babies below 28 weeks (extremely preterm) require intensive NICU care and have higher rates of long-term complications — but survival rates at specialised centres have improved dramatically.
Obstetric Care in Noida and Greater Noida
Dr. Shachi Singh at Prakash Hospital, Sector 33, Noida, assesses and manages threatened preterm labour for women across Noida and Greater Noida.
If you have regular contractions before 37 weeks, call immediately: +91 97023 46853
Clinic Hours: Monday to Saturday, 9 AM – 6 PM | Sunday, 10 AM – 2 PM
Address: D-12A, 12B, Sector-33, G.B. Nagar, Noida, UP 201301
This blog is for educational purposes only.
