Preterm labor comprises 12.7% of all pregnancies. Although the overall rate of pregnancy is decreasing, the occurrence of premature birth due to preterm labor in South Korea has been increasing over the past 7 years. Not only is preterm birth accountable for about a half of all neonatal mortality cases, the neurological deficits in surviving premature infants often lead to problems later in life, such as developmental disorders and respiratory complications. Currently, preterm labor is detected only when expecting mothers experience abnormal symptoms, or when they undergo a routine test like abdominal ultrasound or a laboratory test for vaginal secretions. It is difficult to detect preterm labor early, and there are few treatment options available other than pharmaceutical agents such as anti-contraction medications, with which side effects are of concern.