is open before obtaining a transvaginal ultrasound Obstetrical evaluation is frequently necessary for any adolescent with bleeding during pregnancy Bleeding During Early Pregnancy Among adults in the first trimester of pregnancy presenting to an ED with abdominal pain or vaginal bleeding, approximately 60% have normal pregnancies, 30% have nonviable intrauterine pregnancies, and 10% have ectopic pregnancies In a pregnant patient with abdominal pain or vaginal bleeding in the first trimester, symptoms that favor an intrauterine pregnancy (rather than ectopic) include mild pain, pain located in the midline, and uterine size greater than weeks On examination, the diagnosis of incomplete spontaneous abortion is straightforward if the internal cervical os is open or tissue fragments are visible A normal intrauterine pregnancy should be visible on transabdominal ultrasound when the β-hCG level reaches about 6,000 mIU per mL at the sixth or seventh gestational week (4 to weeks after conception) and should be visible on transvaginal ultrasound when the level reaches between 1,000 and 2,000 mIU per mL at approximately the fifth week of gestation (3 weeks after conception) Visibility on the ultrasound is also operator dependent It should be remembered that β-hCG levels for any given gestational age are higher in twin pregnancies Failure to visualize a gestational sac on transvaginal ultrasound in a patient whose β-hCG level exceeds 3,000 mIU per mL strongly suggests a nonviable pregnancy Among patients with vaginal bleeding, no intrauterine gestational sac on transvaginal sonography, and a β-hCG level of 2,000 mIU per mL or higher, about 40% will miscarry, about 55% will have ectopic pregnancies, and roughly 5% will have normal intrauterine pregnancies The likelihood of ectopic pregnancy is increased in symptomatic patients whose β-hCG levels are less than 1,500 mIU per mL Spontaneous abortion includes threatened, incomplete, complete, septic, and missed abortions During a threatened abortion, the patient has experienced vaginal bleeding but the cervical os remains closed In the case of a threatened abortion, the pregnancy may still be viable and requires close follow-up by an obstetrician Incomplete, complete, and missed abortions occur when a spontaneous miscarriage is occurring or has already occurred The obstetrician or emergency physician may need to complete the evacuation of the products of conception in the case of an incomplete abortion During management for spontaneous abortion, the patient will need close follow-up with an obstetrician and may require admission to the hospital In a normal pregnancy, between days and 42 after conception and above an initial level of 100 mIU per mL, the β-hCG level doubles approximately every days A decline in β-hCG