Gestational trophoblastic disease When US does not show an intrauterine gestational sac, but rather a hyperechoic area in the endometrium with multiple cystic spaces [51], one should consider a complete molar pregnancy, the most common form of GTD. In the earlier part of the first trimester, this classic appearance may be absent and the sonographic findings more variable [52,53]. Complete molar pregnancy can sometimes appear similar to RPOC. Partial molar pregnancy can First Trimester Vaginal Bleeding be more difficult to diagnose sonographically than complete molar pregnancy [54,55] but should be considered if an embryo is present with cystic change in the early placenta. The US findings of partial molar pregnancy overlap those of a nonviable IUP with hydropic degeneration of the early placenta. The hCG is often, but not always, inappropriately elevated with GTD. Definitive diagnosis is based on histopathological evaluation of uterine contents. US Transabdominal Most research studies have used transvaginal US, and there is little evidence in regards to diagnosis of nonviable IUP with transabdominal US alone. Transabdominal US may be adequate in some patients if the diagnosis is clear, such as when a viable IUP and normal adnexa are demonstrated in a patient with no risk factors for heterotopic pregnancy. Transabdominal US is more likely to be adequate later in the first trimester as opposed to the early first trimester. Ectopic pregnancy If an abnormal amount of free intraperitoneal fluid is identified in the pelvis, transabdominal US should be used to evaluate the flanks and dependent locations in the right upper (Morison pouch) and left upper quadrants. It is difficult to reliably predict tubal rupture by US [39]. Larger amounts of free intraperitoneal fluid correlate with ruptured ectopic pregnancy, but in about one-third of cases with a large amount of free intraperitoneal fluid, the fallopian tubes are intact [56].
First Trimester Vaginal Bleeding. Gestational trophoblastic disease When US does not show an intrauterine gestational sac, but rather a hyperechoic area in the endometrium with multiple cystic spaces [51], one should consider a complete molar pregnancy, the most common form of GTD. In the earlier part of the first trimester, this classic appearance may be absent and the sonographic findings more variable [52,53]. Complete molar pregnancy can sometimes appear similar to RPOC. Partial molar pregnancy can First Trimester Vaginal Bleeding be more difficult to diagnose sonographically than complete molar pregnancy [54,55] but should be considered if an embryo is present with cystic change in the early placenta. The US findings of partial molar pregnancy overlap those of a nonviable IUP with hydropic degeneration of the early placenta. The hCG is often, but not always, inappropriately elevated with GTD. Definitive diagnosis is based on histopathological evaluation of uterine contents. US Transabdominal Most research studies have used transvaginal US, and there is little evidence in regards to diagnosis of nonviable IUP with transabdominal US alone. Transabdominal US may be adequate in some patients if the diagnosis is clear, such as when a viable IUP and normal adnexa are demonstrated in a patient with no risk factors for heterotopic pregnancy. Transabdominal US is more likely to be adequate later in the first trimester as opposed to the early first trimester. Ectopic pregnancy If an abnormal amount of free intraperitoneal fluid is identified in the pelvis, transabdominal US should be used to evaluate the flanks and dependent locations in the right upper (Morison pouch) and left upper quadrants. It is difficult to reliably predict tubal rupture by US [39]. Larger amounts of free intraperitoneal fluid correlate with ruptured ectopic pregnancy, but in about one-third of cases with a large amount of free intraperitoneal fluid, the fallopian tubes are intact [56].