What is a preterm labour? Preterm labour is the onset of labour before 37   weeks of gestation.   The easy medical mnemonic for medical students for different causes of pre term labour is " Infected Weak MUM Has Pre-Term labour"   @ Infected & Weak MUM H as Pre-term labour   Infections   Weak Cervix   M ultiple Pregnancy & Uterine distension   U terine Anomalies   M aternal or Fetal Stress   H emorrhage   Infections: Chorionamnionitis is the infection of fetal membranes and is a major cause of Pre-term birth particularly in < 32 weeks.   Weak Cervix: Cervical weakness causes PAINLESS dilation of cervix and there is history of PAINLESS 2nd trimester pregnancy loss. Past history of cervical surgery is a major risk factor.   Multiple Pregnancy & Uterine distension : Uterine distension by multiple pregnancy or less commonly by polyhydra...