US Cervix Transperineal Transperineal US is an alternate approach to transvaginal evaluation of the gravid cervix and may be a complementary method to transabdominal US in certain clinical situations, such as large body habitus or when incomplete distention of the bladder limits transabdominal cervical assessment. The transperineal approach is superior to transabdominal US, although inadequate visualization of the cervix has been reported in up to 22% of patients [26]. An inability to adequately assess the cervix via the transperineal approach may result from shadowing from the symphysis pubis and rectal gas and stool. Adequate assessment by transperineal US is also dependent on sonographer experience. Transperineal assessment of the gravid cervix has been shown to be comparable to TVUS by several studies. Good correlation between CL measurements obtained transperineally and transvaginally have been reported in normal gravid cervix patients at each trimester, and the accuracy improves as the pregnancy progresses [27]. In a study by Hertzberg et al [28], similar levels of diagnostic confidence were achieved via the transperineal and transvaginal approaches, although there was a clear preference expressed by the interpreting physician for the latter. CLs were found to be comparable after 20 weeks gestational age, and CL measured between 14 and 20 weeks gestational age were statistically shorter via the transperineal approach. In a study of women between 22 and 24 weeks gestational age, Cicero et al [26] reported transperineal CL comparable to those obtained transvaginally. Standard second and third trimester transabdominal US evaluation may inadequately visualize the cervix or demonstrate findings suspicious for shortening. In such cases, transvaginal or transperineal US have been recommended for further evaluation [23].
Assessment of Gravid Cervix. US Cervix Transperineal Transperineal US is an alternate approach to transvaginal evaluation of the gravid cervix and may be a complementary method to transabdominal US in certain clinical situations, such as large body habitus or when incomplete distention of the bladder limits transabdominal cervical assessment. The transperineal approach is superior to transabdominal US, although inadequate visualization of the cervix has been reported in up to 22% of patients [26]. An inability to adequately assess the cervix via the transperineal approach may result from shadowing from the symphysis pubis and rectal gas and stool. Adequate assessment by transperineal US is also dependent on sonographer experience. Transperineal assessment of the gravid cervix has been shown to be comparable to TVUS by several studies. Good correlation between CL measurements obtained transperineally and transvaginally have been reported in normal gravid cervix patients at each trimester, and the accuracy improves as the pregnancy progresses [27]. In a study by Hertzberg et al [28], similar levels of diagnostic confidence were achieved via the transperineal and transvaginal approaches, although there was a clear preference expressed by the interpreting physician for the latter. CLs were found to be comparable after 20 weeks gestational age, and CL measured between 14 and 20 weeks gestational age were statistically shorter via the transperineal approach. In a study of women between 22 and 24 weeks gestational age, Cicero et al [26] reported transperineal CL comparable to those obtained transvaginally. Standard second and third trimester transabdominal US evaluation may inadequately visualize the cervix or demonstrate findings suspicious for shortening. In such cases, transvaginal or transperineal US have been recommended for further evaluation [23].