MRI Fetal Without IV Contrast Fetal MRI without IV contrast is not useful as a next imaging study for the evaluation of known or suspected multiple gestations. There is no relevant literature regarding the use of fetal MRI without IV contrast for the evaluation of patients with multiple gestations in the first trimester. US Cervix Transvaginal US cervix transvaginal can be performed as the next imaging study to assess the cervix. In studies specifically evaluating low-risk twin pregnancies, routine TVUS assessment of cervical length in the first trimester (as a component of standard management) has not been shown to predict preterm labor or to be associated with improved outcomes [25,26]. US Duplex Doppler Fetal Middle Cerebral Artery US Doppler of the fetal MCA is not useful as the next imaging study for the evaluation of known or suspected multiple gestations. Early in pregnancy, a discrete fetal MCA is not identifiable, and fetal MCA Doppler cannot be performed. Hence, this examination is not useful in the first trimester [9]. US Duplex Doppler Fetal Umbilical Artery US Doppler of the fetal UA is not routinely used as the next imaging study for the evaluation of known or suspected multiple gestations. An identifiable UA is present in the late first trimester [9]. There is no established role for UA assessment at this gestational age, and hence this examination is not indicated in the first trimester. Multiple Gestations US Echocardiography Fetal US echocardiography can be performed in the first trimester between 12 weeks 0 days and 13 weeks 6 days. Indications for detailed first trimester obstetric US and fetal echocardiography were summarized by AIUM and endorsed by other key societies and include both maternal and fetal indications.
Multiple Gestations. MRI Fetal Without IV Contrast Fetal MRI without IV contrast is not useful as a next imaging study for the evaluation of known or suspected multiple gestations. There is no relevant literature regarding the use of fetal MRI without IV contrast for the evaluation of patients with multiple gestations in the first trimester. US Cervix Transvaginal US cervix transvaginal can be performed as the next imaging study to assess the cervix. In studies specifically evaluating low-risk twin pregnancies, routine TVUS assessment of cervical length in the first trimester (as a component of standard management) has not been shown to predict preterm labor or to be associated with improved outcomes [25,26]. US Duplex Doppler Fetal Middle Cerebral Artery US Doppler of the fetal MCA is not useful as the next imaging study for the evaluation of known or suspected multiple gestations. Early in pregnancy, a discrete fetal MCA is not identifiable, and fetal MCA Doppler cannot be performed. Hence, this examination is not useful in the first trimester [9]. US Duplex Doppler Fetal Umbilical Artery US Doppler of the fetal UA is not routinely used as the next imaging study for the evaluation of known or suspected multiple gestations. An identifiable UA is present in the late first trimester [9]. There is no established role for UA assessment at this gestational age, and hence this examination is not indicated in the first trimester. Multiple Gestations US Echocardiography Fetal US echocardiography can be performed in the first trimester between 12 weeks 0 days and 13 weeks 6 days. Indications for detailed first trimester obstetric US and fetal echocardiography were summarized by AIUM and endorsed by other key societies and include both maternal and fetal indications.