Page 68 - Ebook-Book JCMS 2025

Management of Threatened Preterm Labor Based on Cervical
Length: A Randomized Controlled Trial
Supakorn Chaiyakarn, Puntabut Warintaksa , Piya Chaemsaithong*
Department of Obstetrics and Gynaecology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University
*Corresponding Author E-mail: pchaemsa@hotmail.com
Background: Abstract
A large subset of women with threatened preterm labor is undelivered, therefore, tocolytic
agents and antenatal corticosteroids are given unnecessary. The objective of this study is
to determine whether the use of cervical length for the management of threatened preterm
labor can reduce the number of women who receive inappropriate treatment.
Methods: Results: A randomized control trial including women between 24 to 33+6 weeks of gestation
presenting with threatened preterm labor was conducted. Patients with transvaginal
cervical length between 15-30 mm were randomized into two groups: 1) the expectant
group; and 2) the treatment group. The expectant group was not received corticosteroids
and tocolytic agent while corticosteroids and tocolytic agent were administered in the
treatment group. Cervical length of patients in the expectant management group was
measured every 2-4 hours and the steroids as well as tocolytic agent were initiated only if
there was cervical shortening of >20% or cervical length <15 mm. The primary outcome
was inappropriate treatment defined as undelivered for more than a week after steroids
treatment.
Thirty-eight cases of threatened preterm labor were recruited (18 cases in expectant group
and 20 cases in the treatment group). The rate of inappropriate treatment was significantly
higher in the treatment group compared to the expectant group [90% (17/18) vs. 14%
(2/20); relative risk 0.12; 95% CI: 0.02-0.39)]. The expectant management group had a
significant reduction in the use of corticosteroids and tocolytic agents (30% vs. 100%;
10% vs. 83.3%, respectively). In addition, there were significantly fewer rates of maternal
complications such as maternal tachycardia and hypokalemia in the expectant group (p
<0.05 all). A shorter maternal hospital stays (days) was also significantly observed in the
expectant group [1 (1-14) vs. 3 (1-18); p< 0.01]. All patients remained undelivered within
seven days despite no corticosteroids and tocolytic agent.
Conclusion: Women with threatened preterm labor and cervical length within 15-30 mm without
further cervical shortening can receive expectant management without the administration of
tocolysis and steroids. Such management leads to a reduction in inappropriate treatment,
maternal side effects, and maternal hospital stays.
66 Joint Conference in Medical Sciences 2025