Material and Method: One hundred eighty eight pregnant women with threatened preterm labor between 26 and 35 weeks were enrolled in the present study. Cervical measurement was performed in all patients and divided in two groups. The first group, 60 cases, was patients with cervical length less than 30 mm. The second group, 128 cases, was patients with cervical length 30 mm or greater. All women in each group were randomly inhibited uterine contraction with nifedipine and were bed rest.

Results: If the cervical length was 30 mm or greater, nifedipine and bed rest succeeded to inhibit uterine contraction without statistical significance. Nifedipine was appropriate for contraction inhibition when the cervical length was less than 30 mm with statistical significance.

Conclusion: Nifedipine and bed rest can be used successfully to inhibit contractions in threatened preterm labor. However, nifedipine should be used if the cervical length is less than 30 mm. If cervical length is 30 mm or greater, bed rest should be advised to avoid unnecessary medical intervention.

Keywords: Cervical length, Nifedipine, Bed rest, Threatened preterm labor