ABSTRACT
KEY POINTS • See Chapter 17 for primary and secondary prevention of
preterm birth (PTB) in asymptomatic women, and for risk factors and complications.
• The diagnosis of preterm labor (PTL) is based on the clinical criteria of regular uterine contractions (≥4/20 minutes or ≥8/hour) at 20-36 6/7 weeks with either: • Manually detected cervical dilatation of ≥3 cm, or • Transvaginal ultrasound (TVU) cervical length (CL)
<20 mm, or • TVU CL 20-29 mm and positive fetal bronectin (FFN)
• Threatened PTL (regular uterine contractions (≥4/20 minutes or ≥8/hour) at 20-36 6/7 weeks) should be assessed and managed with knowledge of TVU CL, and FFN results (Figure 18.1).
