Preterm Labor

Excerpt

Preterm labor (PTL) is defined as cervical change that develops in response to regular uterine contractions occurring between 20 0/7 and 36 6/7 weeks of estimated gestational age (EGA). The American College of Obstetricians and Gynecologists (ACOG) also states that PTL can be diagnosed in patients with regular contractions and cervical dilation of at least 2 cm before 37 weeks EGA, while the international guidelines from the World Association of Perinatal Medicine and the Perinatal Medicine Foundation (WAPM-PMF) recommend using a cutoff of at least 3 cm to diagnose spontaneous preterm labor (sPTL).

Spontaneous PTL is unlikely to resolve once the cervix reaches at least 3 cm. However, treatment also benefits patients who are at high risk of preterm delivery, even if they have not yet reached 3 cm dilation. Most patients presenting with symptoms of sPTL will usually deliver at term. Therefore, when patients present with symptoms of sPTL, the evaluation should focus on attempting to identify patients whose labor will progress and result in preterm birth (PTB). PTL can be classified as extremely preterm. Spontaneous PTL with intact membranes is responsible for 40% to 45% of all PTBs, which, in turn, are associated with substantially higher rates of neonatal morbidity and mortality compared to neonates born after 37 weeks EGA. For this reason, accurate diagnosis and management of sPTL is imperative for improving neonatal outcomes.