Premature labour or preterm labour is when your labour starts more than three weeks before your due date i.e. before the 37th week of pregnancy. An estimated 15 million babies are born preterm every year and this number is rising according to the World Health Organisation (WHO). Babies born premature can have lifelong or life-threatening health problems later in life. Premature infants are also at risk of sudden infant death syndrome (SIDS). Preterm birth complications are also a common cause of death among children under 5 years of age . Doctors don't always know for sure what causes preterm labour