Although the Cesarean section is one of the most common obstetric operations around the world, the World Health Organization recognizes that where cesarean rates are higher than 10%, there is no increase in beneficial maternal and newborn outcomes. some researchers noted that in countries where cesarean rates are above 15%, populations experience higher maternal, infant, and neonatal mortality rates. infants born by cesarean delivery are more likely to require neonatal intensive care unit and have greater respiratory complications, and higher odds for childhood asthma, and obesity.

Preterm is defined as babies born alive before completing 37 weeks of pregnancy.

Preventing Preterm birth is a global priority due to increased risk for neonatal morbidity and mortality.

Inclusion Criteria:

1. singleton pregnant
2. gestational age at 18 weeks
3. previous vaginal or Cesarean section

Exclusion Criteria:

1. twins pregnancy in their second birth
2. previous preterm labor
3. diabetic during the second pregnancy
4. hypertensive during the second pregnancy
5. cigarette use during the second pregnancy
6. congenital anomalies