Cervical length evaluation by transvaginal sonography in nongravid women with a history of preterm delivery

Objective: To evaluate cervical length in the nongravid period in women with a past history of preterm delivery.

Methods: The study population comprised 54 women who had delivered spontaneously before 34 weeks of gestation. Etiology of preterm delivery was suspected to be related to cervical incompetence, defined as a painless and progressive dilatation of the cervix in the absence of other causes. Patients with pre-eclampsia, intrauterine growth restriction, uterine anomalies, fetal anomalies, multiple gestation and similar complications were excluded. Shortening of the cervix was recorded during pregnancy in all study patients. One hundred and four women matched for age, parity and body mass index who had given birth at term served as the control group. Cervical length was evaluated in all women at least 12 weeks after delivery by transvaginal sonography in the mid-sagittal plane.

Results: The mean gestational age at delivery was 30.8 +/- 1.2 weeks in the study group and 38.8 +/- 2.1 weeks in the control group (P = 0.03). The mean cervical length in the two groups was 36 +/- 6 and 38 +/- 4 mm, respectively. This difference was not statistically significant (P = 0.9).

Conclusions: In nongravid women with unexplained preterm delivery there is no difference in cervical length compared to patients who deliver at term. Shortening of the cervix is most probably a reversible phenomenon that occurs during pregnancy and represents a failure of the competence mechanism to adapt to pregnancy.