The aim of the current study is to assess the accuracy of maternal serum amyloid A for prediction of preterm labor in women with threatened preterm labor.

Inclusion Criteria:

• Pregnant women, age 18 - 35.
• Gestational age: 28 - 36+6 weeks.
• Singleton pregnancy.
• No past history of any medical disorder and with no other medical complications during pregnancy
• Nonsmoker.
• Diagnosis of preterm labor is based on the American College of Obstetricians and Gynecologists Guidelines

Criteria of preterm delivery:

1. Gestational age: 28 - 36+6 weeks
2. Presence of uterine contractions (at least 4 in 20 minutes or 8 in 60 minutes)
3. cervical dilation ≥ 4 cm
4. Cervical effacement ≥ 80%.

Exclusion Criteria:

• Of any patient with the following risk factors for preterm labor:

  • Over distended uterus .
  • hemorrhage
  • Uterine anomalies

58 pregnant women will be recruited