Clotted blood in the pelvis can sometimes be mistaken for mesentery or blend in with adjacent organs such as the uterus and be difficult to recognize. US Duplex Doppler When a normal or potentially normal IUP is present, pulsed Doppler US (whether spectral, color, or power Doppler) of the pregnancy should generally be avoided in the first trimester due to concerns about potential bioeffects in the developing embryo [57-59]. Documentation of embryonic cardiac activity is best done with M- mode US as the heart rate can be measured. Video clips can also be used to document embryonic cardiac activity. Once a normal IUP has been excluded, Doppler US may be useful when other diagnoses such as RPOC are suspected. Doppler US is not generally needed to make a diagnosis of GTD, but may be helpful as an ancillary tool in the management of some patients with GTD [60,61]. Doppler US is rarely useful for diagnosing tubal pregnancies as both the corpus luteum and a tubal pregnancy often have flow detected peripherally. Although Doppler US could conceivably be useful in some nontubal ectopic pregnancies such as cervical, interstitial, or Cesarean section scar pregnancies, its diagnostic utility for these diagnoses has not been well established in the literature. MRI While an early pregnancy may be recognized on MRI, it generally is due to unintentional imaging of the pregnancy [67]. MRI is rarely needed for evaluating an IUP or tubal pregnancy. However, one may occasionally recognize tubal pregnancies on MRI [68], and MRI may be helpful as a problem-solving tool for nontubal ectopic pregnancies or GTD [69-71]. MRI may also help in cases of unusual implantation sites or in women with uterine anomalies. In pregnancy, gadolinium should be used with caution and only when critical and the potential benefits are felt to be justified [72]. Gadolinium is not generally recommended in a normal first-trimester pregnancy. MRI without gadolinium is thought to be safe in the first trimester of pregnancy [73].
First Trimester Vaginal Bleeding. Clotted blood in the pelvis can sometimes be mistaken for mesentery or blend in with adjacent organs such as the uterus and be difficult to recognize. US Duplex Doppler When a normal or potentially normal IUP is present, pulsed Doppler US (whether spectral, color, or power Doppler) of the pregnancy should generally be avoided in the first trimester due to concerns about potential bioeffects in the developing embryo [57-59]. Documentation of embryonic cardiac activity is best done with M- mode US as the heart rate can be measured. Video clips can also be used to document embryonic cardiac activity. Once a normal IUP has been excluded, Doppler US may be useful when other diagnoses such as RPOC are suspected. Doppler US is not generally needed to make a diagnosis of GTD, but may be helpful as an ancillary tool in the management of some patients with GTD [60,61]. Doppler US is rarely useful for diagnosing tubal pregnancies as both the corpus luteum and a tubal pregnancy often have flow detected peripherally. Although Doppler US could conceivably be useful in some nontubal ectopic pregnancies such as cervical, interstitial, or Cesarean section scar pregnancies, its diagnostic utility for these diagnoses has not been well established in the literature. MRI While an early pregnancy may be recognized on MRI, it generally is due to unintentional imaging of the pregnancy [67]. MRI is rarely needed for evaluating an IUP or tubal pregnancy. However, one may occasionally recognize tubal pregnancies on MRI [68], and MRI may be helpful as a problem-solving tool for nontubal ectopic pregnancies or GTD [69-71]. MRI may also help in cases of unusual implantation sites or in women with uterine anomalies. In pregnancy, gadolinium should be used with caution and only when critical and the potential benefits are felt to be justified [72]. Gadolinium is not generally recommended in a normal first-trimester pregnancy. MRI without gadolinium is thought to be safe in the first trimester of pregnancy [73].