Effect of intra-amniotic fluid pressure from polyhydramnios on cervical length in patients with twin-twin transfusion syndrome undergoing fetoscopic laser surgery.

OBJECTIVES: To determine the relationship between intra-amniotic pressure and cervical length (CL) in patients with twin-twin transfusion syndrome (TTTS) undergoing fetoscopic laser photocoagulation (FLP), and to identify pre- or intraoperative factors associated with increased intra-amniotic pressure in this population. METHODS: This was a prospective cohort study of patients undergoing FLP for TTTS. Exclusion criteria were triplet or higher-order gestation and prior cervical cerclage, amnioreduction or FLP procedure. CL was assessed using preprocedure transvaginal ultrasound. Intra-amniotic pressure measurements were obtained on initial placement of the trocar into the amniotic cavity, using a direct hydrostatic pressure gauge. The relationship between intra-amniotic pressure and CL was assessed using multivariate linear regression analysis, including relevant preoperative and intraoperative variables. RESULTS: In total, 283 pregnancies met the inclusion criteria. Quintero stage of TTTS was I in 33 pregnancies, II in 88, III in 150 and IV in 12. Mean gestational age (GA) at FLP was 20.7 ± 3 weeks. Mean intra-amniotic pressure was 23.1 ± 9 mmHg. On unadjusted linear regression analysis, there was no significant association between intra-amniotic pressure and preoperative CL (P = 0.24) or GA at delivery (P = 0.22). On multivariate analysis, the factors associated significantly with intra-amniotic pressure were: number of prior term deliveries (P = 0.03), recipient maximum vertical pocket (P < 0.0001), Quintero stage IV (P = 0.01) and type of anesthesia (sedation vs general anesthesia; P = 0.01). CONCLUSION: In pregnancies with TTTS, intra-amniotic pressure is not associated with CL or GA at delivery. This novel finding suggests that cervical shortening in this population is not mechanically driven. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Avaliação do comprimento do colo uterino em gestantes normais entre 20 e 34 semanas de gestação por meio da ultrassonografia endovaginal / Endovaginal sonographic assessment of cervical length in healthy pregnant women between 20 and 34 gestational weeks

OBJETIVO: Avaliar o comprimento do colo uterino pela ultrassonografia transvaginal em uma população de gestantes normais e construir uma curva de normalidade no período de 20 a 34 semanas de gestação. MATERIAIS E MÉTODOS: Estudo de corte transversal, incluindo 145 gestantes normais, com feto único, vivo, sem enfermidades, entre 20 e 34 semanas de gravidez, examinadas nos serviços de ultrassonografia do Hospital Universitário Júlio Müller e de uma clínica privada. As gestantes foram submetidas a ultrassonografia endovaginal, com registro do comprimento cervical. Critérios de exclusão foram: parto prematuro, rotura prematura pré-termo das membranas, placenta prévia, uso de fármacos tocolíticos e/ou progesterona, cerclagem ou qualquer intervenção cirúrgica prévia no colo. A associação entre o comprimento do colo uterino e a idade gestacional foi examinada por regressão linear. RESULTADOS: O comprimento cervical diminuiu progressivamente em 0,8 mm a cada semana, à medida que a idade gestacional progrediu (r = -0,351; p < 0,001). As mulheres que tiveram afunilamento cervical apresentaram colo mais curto que as demais (p = 0,001). A interpolação dos percentis 5, 50 e 95 provê gráfico passível de ser utilizado como referência. CONCLUSÃO: O comprimento médio cervical em gestantes normais diminui 0,8 mm por semana, entre a 20ª e a 34ª semanas de gestação.

OBJECTIVE: To evaluate the cervical length by means of transvaginal ultrasonography in a population of healthy pregnant women, developing a normality curve in the period between the 20th and 34th gestational weeks. MATERIALS AND METHODS: Cross sectional study involving 145 healthy singleton pregnancies with healthy fetuses between 20 and 34 weeks of gestation, evaluated at the units of ultrasonography of Hospital Universitário Júlio Müller and of a private center. Each pregnant woman underwent a single transvaginal ultrasonography study, with measurement and recording of the cervical length. Exclusion criteria were: preterm labor, preterm premature rupture of membranes, placenta previa, use of tocolytics and/or progesterone, cerclage or any surgical intervention prior to pregnancy. The association between cervical length and gestational age was evaluated by linear regression analysis. RESULTS: The cervical length presented a progressive decrease (0.8 mm/week) as the gestational age progressed (r = -0.351; p < 0.001). The women with cervical funneling presented shorter cervix (p = 0.001). Interpolation of the 5th, 50th and 95th percentiles provides a graph to be used as a reference. CONCLUSION: The mean cervical length decreases about 0.8 mm per week in the period between the 20th and 34th gestational weeks.