MATERNAL POSITION AND ULTRASONIC CERVICAL ASSESSMENT IN MULTIPLE PREGNANCY - PRELIMINARY-OBSERVATIONS

OBJECTIVE: To evaluate the influence of position on the functional ana tomy of the cervix. STUDY DESIGN: Cervical length and width of the int ernal of were measured by transvaginal ultrasound in the recumbent and standing position from 15 gestational weeks to term in 15 twin and 3 triplet pregnancies. Measurements on asymptomatic primigravidae with t wins who delivered vaginally after 36 weeks were made to calculate tre nds in normal twin pregnancies. These data were compared with that obt ained in patients who had threatened preterm labor. RESULTS: As the to tal observation period progressed, the mean cervical length decreased from 50 to 27 mm in the recumbent position and from 48 to 21 mm in the standing position (P < .001). The differences between the values obta ined in the recumbent and standing position increased from 5% to 31% a s pregnancy progressed (P < .001). Funnelling was observed from 20 wee ks onwards in the erect position but only after 35 weeks in the recumb ent position. CONCLUSION Our preliminary observations support a policy aimed at prevention of prematurity by reducing physical activity and standing work in patients who have multiple gestations. The full impac t of these observations on the early defection of special risk groups and the prescription of preventive interventions have yet to be evalua ted.