This information is critical for the detection and staging of TTTS and for the evaluation of fetuses diagnosed with sFGR [9,42]. US Pregnant Uterus Biophysical Profile BPP can be performed in the third trimester to assess fetal well-being. Frequency of BPP can be determined based on the presence of risk factors and impending complications [53,64]. To date, there are insufficient data in the literature to suggest that antenatal surveillance of twins with BPP is beneficial in the setting of reactive nonstress test or in the absence of associated risk factors [62,63]. US Pregnant Uterus Transabdominal Transabdominal US of the pregnant uterus continues to be the mainstay for the evaluation and surveillance of MC twins. For MC twins, sonographic surveillance usually begins at 16 weeks and is done every 2 weeks thereafter [9,12]. Due to variability and SDs in measurements, growth and biometry is usually performed no more frequently than every 2 weeks. The discordance in estimated fetal weights should be calculated and documented at each scan. If prior history of cesarean delivery or uterine instrumentation is present, assessment for placenta accreta spectrum can be performed. US Pregnant Uterus Transvaginal Transvaginal examination of the pregnant uterus and cervix can be performed as an adjunct for limited transabdominal fetal evaluation. Additional indications include assessment of the cervix and placenta and detection of vasa previa. Typically, transvaginal imaging is performed only if transabdominal evaluation is considered suboptimal or incomplete. If prior history of cesarean delivery or uterine instrumentation is present, assessment for placenta accreta spectrum can be performed. Variant 7: Multiple gestations. Dichorionic or multichorionic higher order multiples or monochorionic gestations. Known abnormality or discordance between fetuses (fluid, size, weight). Growth and antepartum surveillance.
Multiple Gestations. This information is critical for the detection and staging of TTTS and for the evaluation of fetuses diagnosed with sFGR [9,42]. US Pregnant Uterus Biophysical Profile BPP can be performed in the third trimester to assess fetal well-being. Frequency of BPP can be determined based on the presence of risk factors and impending complications [53,64]. To date, there are insufficient data in the literature to suggest that antenatal surveillance of twins with BPP is beneficial in the setting of reactive nonstress test or in the absence of associated risk factors [62,63]. US Pregnant Uterus Transabdominal Transabdominal US of the pregnant uterus continues to be the mainstay for the evaluation and surveillance of MC twins. For MC twins, sonographic surveillance usually begins at 16 weeks and is done every 2 weeks thereafter [9,12]. Due to variability and SDs in measurements, growth and biometry is usually performed no more frequently than every 2 weeks. The discordance in estimated fetal weights should be calculated and documented at each scan. If prior history of cesarean delivery or uterine instrumentation is present, assessment for placenta accreta spectrum can be performed. US Pregnant Uterus Transvaginal Transvaginal examination of the pregnant uterus and cervix can be performed as an adjunct for limited transabdominal fetal evaluation. Additional indications include assessment of the cervix and placenta and detection of vasa previa. Typically, transvaginal imaging is performed only if transabdominal evaluation is considered suboptimal or incomplete. If prior history of cesarean delivery or uterine instrumentation is present, assessment for placenta accreta spectrum can be performed. Variant 7: Multiple gestations. Dichorionic or multichorionic higher order multiples or monochorionic gestations. Known abnormality or discordance between fetuses (fluid, size, weight). Growth and antepartum surveillance.