Composite morphometric/morphographic ultrasound parameters of the second trimester cervix for the prediction of spontaneous preterm labor

RESUMO

There is need for simple, cheap and highly predctive test for spontaneous preterm labor (SPL). The "zone of endocervical crypts (ZEC)" is a well-defined sonographic landmark corresponding to enfolding of the endocervical mucosa. Early loss of ZEC might be considered as indicative of "premature effacement". We tested the efficacy of a "composite" parameter of cervical length plus ZEC loss for the prediction SPL.MATERIAL/METHODS The study included singleton pregnant women attending Asyout Clinic for Gynecology andObstetrics between 20 and <24 weeks' gestation. Transvaginal ultrasonography was used fora) measuring the cervical length, and, b) detecting the existence/non-existance of ZEC.* Cervical lengthwas measured as the distance between the internal os of the cervix and theexternal os.* The Zone of Endocervical Crypts (ZEC) was defined as the heteroechoic area around thecervical canal (CC). Monoechoic appearance of the cervix was described as loss of the ZEC.The sensitivity, specificity, positive and negative predictive values (PPV,NPV) were calculated. RESULTS: Two thousand and one pregnancies were evaluated for the incidence and sonographic prediction of SPL (24 - <32 weeks, and 32-36 weeks).The overall SPL rate was 9%.Loss of ZEC, and, the combined ZEC loss with shortened cervix were found to have better specificity and better PPV than the cervical shortening alone. ZEC loss had better PPV for early rather than late PL."Funneling" had poor PPV, but, is still a good "negative". CONCLUSION: The composite parameter of the "lost ZEC" and short cervix is superior to the cervical length alone for the early prediction of SPL. Wider scale study is now being run for a) ensuring the reproducibility of the parameter testing values, and b) to find any correlation between the ZEC loss and other clinical criteria