Table 1 PTB risk factors, prevention, and management. Evidence is summarized in reference [2]

The physiological mechanisms behind PTB remain largely unknown, although a number of risk factors have been described. Medical risk factors include infections, non-communicable diseases and their risk factors (diabetes, hypertension), and multiple pregnancies; social risk factors include low or high maternal age, poverty, and receiving antenatal care for the first time at a late stage in the pregnancy; and behavioral risk factors include tobacco, alcohol, substance use, and stress.

The Born Too Soon report summarized the key evidence-based interventions for preventing PTB and for reducing mortality among those born prematurely [2].

Prevention focuses on prenatal care (e.g., education, nutrition, treatment of sexually transmitted infections, family planning); antenatal care; obstetric care; and policies to tackle risk factors, such as smoking in pregnancy.

Reducing mortality focuses on newborn care (e.g., feeding, thermal care); kangaroo care; neonatal resuscitation if needed; management of complications; and neonatal intensive care, if needed.

Managing preterm labor can both prevent PTB and reduce mortality among premature babies. Such management includes antenatal corticosteroids; antibiotics for premature rupture of the membranes; and tocolytics to slow down preterm labor.

Broader social, financial, agricultural and other policies that are being investigated for their potential role in reducing the burden of PTB include measures to improve household food security; conditional cash transfers to increase patient uptake of services; and performance-based financing to improve quality of care.