Note from the American College of Radiology (ACR) and the National Guideline Clearinghouse (NGC): ACR has added Relative Radiation Levels to their Appropriateness Criteria tables. See the original guideline document for details.
ACR Appropriateness Criteria®
Clinical Condition: First Trimester Bleeding
Variant 1: +B HCG 5 weeks gestational age by history. No sac seen in uterus.
Radiologic Exam Procedure |
Appropriateness Rating |
Comments |
US, pregnant, uterus, transvaginal (TV), first with or without transabdominal (TA) |
8 |
|
US, follow-up scan in 7-10 days |
8 |
|
B hCG-every 2 days |
8 |
|
US, follow-up scan in 2 or 3 days |
6 |
|
US, pregnant, uterus, adnexa, Doppler |
4 |
|
US, pregnant, uterus, endometrium, Doppler |
4 |
|
US, pregnant, uterus, transvaginal (TV) only |
4 |
|
B hCG-every 7 days |
4 |
|
US, pregnant, uterus, transabdominal (TA) only |
2 |
|
US, pregnant, uterus, transabdominal (TA) first with or without TV |
2 |
|
D & C |
2 |
|
Laparoscopy |
2 |
|
Appropriateness Criteria Scale
1 2 3 4 5 6 7 8 9
1 = Least appropriate 9 = Most appropriate
|
Note: Abbreviations used in the tables are listed at the end of the "Major Recommendations" field.
Variant 2: 5 weeks gestational age. Fetal Heart Rate = 85.
Radiologic Exam Procedure |
Appropriateness Rating |
Comments |
US, pregnant, uterus, transvaginal (TV), first with or without transabdominal (TA) |
8 |
|
US, measure MSD - CR length |
8 |
|
US, follow-up scan in 7-10 days |
8 |
|
US, pregnant, uterus, transvaginal (TV) only |
6 |
|
US, pregnant, uterus, uteroplacental circumference, Doppler |
4 |
|
US, follow-up scan in 2 or 3 days |
4 |
|
US, pregnant, uterus transabdominal (TA) only |
2 |
|
US, pregnant, uterus, transabdominal (TA) first with or without TV |
2 |
|
B hCG-every 2 days |
2 |
|
B hCG-every 7 days |
2 |
|
D & C |
2 |
|
Appropriateness Criteria Scale
1 2 3 4 5 6 7 8 9
1 = Least appropriate 9 = Most appropriate
|
Note: Abbreviations used in the tables are listed at the end of the "Major Recommendations" field.
Variant 3: 5 weeks gestational age. Fetal Heart Rate = 110.
Radiologic Exam Procedure |
Appropriateness Rating |
Comments |
US, pregnant, uterus, transvaginal (TV) only |
8 |
Either TV or TA can be used. |
US, pregnant, uterus, transvaginal (TV), first with or without transabdominal (TA) |
8 |
Either TV or TA can be used. |
US, measure MSD - CR length |
8 |
|
US, follow-up scan in 2nd trimester |
4 |
|
US, pregnant, uterus, transabdominal (TA) only |
2 |
|
US, pregnant, uterus, transabdominal (TA) first with or without transvaginal (TV) |
2 |
|
US, pregnant, uterus, uteroplacental circumference Doppler |
2 |
|
US, follow-up scan in 7 days |
2 |
|
US, follow-up scan in 3rd trimester |
2 |
|
Appropriateness Criteria Scale
1 2 3 4 5 6 7 8 9
1 = Least appropriate 9 = Most appropriate
|
Note: Abbreviations used in the tables are listed at the end of the "Major Recommendations" field.
Variant 4: 5 weeks gestational age. Fetal Heart Rate = 110. Moderate subchorionic hemorrhage.
Radiologic Exam Procedure |
Appropriateness Rating |
Comments |
US, pregnant, uterus, transvaginal (TV) only |
8 |
Either TV or TA can be used. |
US, pregnant, uterus, transvaginal (TV), first with or without transabdominal (TA) |
8 |
Either TV or TA can be used. |
US, measure MSD - CR length |
8 |
|
US, follow-up scan in 7 days |
6 |
|
US, follow-up scan in 2nd trimester |
4 |
|
US, follow-up scan in 3rd trimester |
4 |
|
US, pregnant, uterus, transabdominal (TA) first with or without transvaginal (TV) |
4 |
|
US, pregnant, uterus, transabdominal (TA) only |
2 |
|
US, pregnant, uterus, uteroplacental circumference, Doppler |
2 |
|
Appropriateness Criteria Scale
1 2 3 4 5 6 7 8 9
1 = Least appropriate 9 = Most appropriate
|
Note: Abbreviations used in the tables are listed at the end of the "Major Recommendations" field.
Variant 5: + B HCG 7 weeks gestational age by history. No sac seen in uterus.
Radiologic Exam Procedure |
Appropriateness Rating |
Comments |
US, pregnant, uterus, transvaginal (TV), first with or without transabdominal (TA) |
8 |
|
US, follow-up scan in 2 days |
8 |
|
B hCG-every 2 days |
8 |
|
US, pregnant, uterus, adnexa, Doppler |
6 |
|
US, pregnant, uterus, transvaginal (TV) only |
4 |
|
US, pregnant, uterus, transabdominal (TA) first with or without transvaginal (TV) |
4 |
|
US, pregnant, uterus, endometrium, Doppler |
4 |
|
US, follow-up scan in 7 days |
4 |
|
B hCG-every 7 days |
4 |
|
Laparoscopy |
4 |
|
US, pregnant, uterus, transabdominal (TA) only |
2 |
|
D & C |
2 |
|
Appropriateness Criteria Scale
1 2 3 4 5 6 7 8 9
1 = Least appropriate 9 = Most appropriate
|
Note: Abbreviations used in the tables are listed at the end of the "Major Recommendations" field.
Variant 6: 7 weeks gestational age. CRL = 9 mm - FHM.
Radiologic Exam Procedure |
Appropriateness Rating |
Comments |
US, pregnant, uterus, transvaginal (TV) only |
8 |
Either TV or TA can be used. |
US, pregnant, uterus, transvaginal (TV), first with or without transabdominal (TA) |
8 |
Either TV or TA can be used. |
D & C |
8 |
|
US, pregnant, uterus, transabdominal (TA) only |
2 |
|
US, pregnant, uterus, transabdominal (TA) first with or without transvaginal (TV) |
2 |
|
US, measure MSD - CR length |
2 |
|
US, measure yolk sac diameter |
2 |
|
US, pregnant, uterus, uteroplacental circ. Doppler |
2 |
|
US, follow-up scan in 2 days |
2 |
|
US, follow-up scan in 7 days |
2 |
|
B hCG-every 2 days |
2 |
|
B hCG-every 7 days |
2 |
|
Appropriateness Criteria Scale
1 2 3 4 5 6 7 8 9
1 = Least appropriate 9 = Most appropriate
|
Note: Abbreviations used in the tables are listed at the end of the "Major Recommendations" field.
Variant 7: 7 weeks gestational age. Fetal heart rate = 90.
Radiologic Exam Procedure |
Appropriateness Rating |
Comments |
US, pregnant, uterus, transvaginal (TV) only |
8 |
Either TV or TA can be used. |
US, pregnant, uterus, transvaginal (TV), first with or without transabdominal (TA) |
8 |
Either TV or TA can be used. |
US, follow-up scan in 7-10 days |
8 |
|
US, measure MSD - CR length |
6 |
|
US, measure yolk sac diameter |
6 |
|
US, pregnant, uterus, uteroplacental circ. Doppler |
4 |
|
US, follow-up scan in 2 or 3 days |
4 |
|
B hCG-every 7 days |
4 |
|
US, pregnant, uterus, transabdominal (TA) first with or without transvaginal (TV) |
2 |
|
US, pregnant, uterus, transabdominal (TA) only |
2 |
|
B hCG-every 2 days |
2 |
|
D & C |
2 |
|
Appropriateness Criteria Scale
1 2 3 4 5 6 7 8 9
1 = Least appropriate 9 = Most appropriate
|
Note: Abbreviations used in the tables are listed at the end of the "Major Recommendations" field.
Variant 8: 7 weeks gestational age. Fetal heart rate = 130.
Radiologic Exam Procedure |
Appropriateness Rating |
Comments |
US, pregnant, uterus, Transvaginal (TV) only |
8 |
Either TV or TA can be used. |
US, pregnant, uterus, transabdominal (TA) first with or without transvaginal (TV) |
8 |
Either TV or TA can be used. |
US, pregnant, uterus, transvaginal (TV), first with or without transabdominal (TA) |
8 |
Either TV or TA can be used. |
US, measure MSD - CR length |
6 |
|
US, follow-up scan in 3rd trimester |
4 |
|
US, pregnant, uterus, transabdominal (TA) only |
2 |
|
US, pregnant, uterus, uteroplacental circ. Doppler |
2 |
|
US, follow-up scan in 7 days |
2 |
|
US, follow-up scan in 2nd trimester |
No Consensus |
|
Appropriateness Criteria Scale
1 2 3 4 5 6 7 8 9
1 = Least appropriate 9 = Most appropriate
|
Note: Abbreviations used in the tables are listed at the end of the "Major Recommendations" field.
Variant 9: +B HCG 9 weeks gestational age by history. No sac seen in uterus.
Radiologic Exam Procedure |
Appropriateness Rating |
Comments |
US, pregnant, uterus, transvaginal (TV), first with or without transabdominal (TA) |
8 |
|
US, pregnant, uterus, transvaginal (TV) only |
8 |
|
US, follow-up scan in 7-10 days |
8 |
|
B hCG-every 2 days |
8 |
|
US, pregnant, uterus, adnexa, Doppler |
6 |
|
US, pregnant, uterus, transabdominal (TA) first with or without transvaginal (TV) |
4 |
|
US, pregnant, uterus, endometrium Doppler |
4 |
|
US, follow-up scan in 2-3 days |
4 |
|
B hCG-every 7 days |
4 |
|
D & C |
4 |
|
Laparoscopy |
4 |
|
US, pregnant, uterus, transabdominal (TA) only |
2 |
|
Appropriateness Criteria Scale
1 2 3 4 5 6 7 8 9
1 = Least appropriate 9 = Most appropriate
|
Note: Abbreviations used in the tables are listed at the end of the "Major Recommendations" field.
Variant 10: 9 weeks gestational age. CRL = 23 mm -- FHM.
Radiologic Exam Procedure |
Appropriateness Rating |
Comments |
US, pregnant, uterus, transvaginal (TV) only |
8 |
Either TV or TA can be used. |
US, pregnant, uterus, transvaginal (TV), first with
or without transabdominal (TA) |
8 |
Either TV or TA can be used. |
D & C |
8 |
|
US, pregnant, uterus, transabdominal (TA) only |
2 |
|
US, pregnant, uterus, transabdominal (TA) first with or without transvaginal (TV) |
2 |
|
US, measure MSD - CR length |
2 |
|
US, measure yolk sac diameter |
2 |
|
US, pregnant, uterus, uteroplacental circ. Doppler |
2 |
|
US, follow-up scan in 2 days |
2 |
|
US, follow-up scan in 7 days |
2 |
|
B hCG-every 2 days |
2 |
|
B hCG-every 7 days |
2 |
|
Appropriateness Criteria Scale
1 2 3 4 5 6 7 8 9
1 = Least appropriate 9 = Most appropriate
|
Note: Abbreviations used in the tables are listed at the end of the "Major Recommendations" field.
Variant 11: 9 weeks gestational. Fetal heart rate = 90.
Radiologic Exam Procedure |
Appropriateness Rating |
Comments |
US, pregnant, uterus, transvaginal (TV) only |
8 |
Either TV or TA can be used. |
US, pregnant, uterus, transvaginal (TV), first with or without transabdominal (TA) |
8 |
Either TV or TA can be used. |
US, pregnant, uterus, transabdominal (TA) first with or without transvaginal (TV) |
8 |
Either TV or TA can be used. |
US, measure MSD - CR length |
8 |
|
US, measure yolk sac diameter |
8 |
|
US, follow-up scan in 7-10 days |
8 |
|
US, follow-up scan in 2 or 3 days |
6 |
|
US, pregnant, uterus, uteroplacental circ. Doppler |
4 |
|
US, pregnant, uterus, transabdominal (TA) only |
2 |
|
B hCG-every 2 days |
2 |
|
B hCG-every 7 days |
2 |
|
D & C |
2 |
|
Appropriateness Criteria Scale
1 2 3 4 5 6 7 8 9
1 = Least appropriate 9 = Most appropriate
|
Note: Abbreviations used in the tables are listed at the end of the "Major Recommendations" field.
Variant 12: 9 weeks gestational. Fetal heart rate = 130.
Radiologic Exam Procedure |
Appropriateness Rating |
Comments |
US, pregnant, uterus, transvaginal (TV) only |
8 |
Either TV or TA can be used. |
US, pregnant, uterus, transabdominal (TA) first with or without transvaginal (TV) |
8 |
Either TV or TA can be used. |
US, pregnant, uterus, transabdominal (TA) only |
6 |
|
US, follow-up scan in 2nd trimester |
5 |
|
US, pregnant, uterus, transvaginal (TV), first with or without transabdominal (TA) |
4 |
|
US, follow-up scan in 3rd trimester |
4 |
|
US, measure MSD - CR length |
2 |
|
US, pregnant, uterus, uteroplacental circ. Doppler |
2 |
|
US, follow-up scan in 7 days |
2 |
|
Appropriateness Criteria Scale
1 2 3 4 5 6 7 8 9
1 = Least appropriate 9 = Most appropriate
|
Note: Abbreviations used in the tables are listed at the end of the "Major Recommendations" field.
First trimester vaginal bleeding is very common, occurring in approximately 25% of patients who are known to be pregnant. In many patients the bleeding is self-limited and is probably due to implantation of the conceptus into the decidualized endometrium.
If the bleeding is not self-limited and is accompanied by severe pain, uterine contractions, and a dilated cervix, the clinical changes are irreversible and the pregnancy is doomed to failure. Because these clinical changes are irreversible, ultrasound has little to offer.
If bleeding and cramping are relatively mild and the cervix is long and closed, the diagnosis is threatened abortion. Analysis of this group reveals that 50% have an abnormal outcome, with the differential diagnosis encompassing a broad spectrum of conditions including a normal intrauterine pregnancy (IUP) (50% of patients), an abnormal living intrauterine pregnancy, a missed abortion, a blighted ovum, retained products of conception, ectopic pregnancy, and gestational trophoblastic disease. Ultrasound examination is especially important in these patients, because the findings may be pivotal not only for determining the precise cause of the bleeding but also for suggesting appropriate therapy.
In comparison to abdominal imaging, the literature emphasizes that in patients with threatened abortion, vaginal sonography is more effective not only for making the specific diagnosis of ectopic pregnancy but also for clarifying indeterminate findings noted on transabdominal scans. In general, if the gestational age is less than 8 or 9 weeks, the sonographic examination should begin using a vaginal approach. If the study is incomplete or inconclusive, an abdominal approach may offer complementary information. A transabdominal approach is often satisfactory in the late first trimester of 9 weeks or more. Nonetheless, in difficult, abnormal, or inconclusive cases, a vaginal examination should also be done in an effort to clarify the findings.
When evaluating a patient with threatened abortion, it is most important to determine if an intrauterine gestational sac is visible and whether or not it has a normal appearance. Using transabdominal ultrasound, an intrauterine sac should normally be visible when the beta hCG is >1800 mIU/mL (2nd International Standard [IS]) or >3240 mIU/mL (International Reference Preparation [IRP]), and a yolk sac and embryo should be detected when MSDs are 20 and 25 mm, respectively. Using a vaginal transducer, the discriminatory beta hCG level for sac detection is 1000 mIU/mL (2nd IS) or 1800 mIU/mL (IRP); and a yolk sac and embryo should be detected when their MSDs are 8 and 16 mm, respectively. In questionably abnormal cases, a follow-up ultrasound should be considered. Knowing that the MSD normally increases by 1 mm/day allows the sonologist to recommend an appropriate time interval between the initial and follow-up examination(s). Although not universally accepted, many sonologists also recommend a second trimester sonographic examination to screen for abnormalities that were unsuspected during the first trimester.
Once an embryo is detected, cardiac activity is normally visible by transabdominal imaging when the CRL is 9 mm; the corresponding CRL on a vaginal scan is 4-5 mm. Despite cardiac activity, sonography may reveal findings that suggest a poor outcome; these include bradycardia (abnormal at <6.2 weeks is <100 beats per minute (BPM); abnormal between 6.3-7 weeks is <120 BPM, an oligohydramniotic sac (abnormal = MSD - CRL <5 mm), or an abnormal appearing yolk sac (diameter >5 mm), and/or amnion (abnormally large amniotic cavity, or an "empty" amniotic cavity). Whether or not a subchorionic hemorrhage is associated with an abnormal outcome (either at the time of initial bleeding), or perinatally, is unclear. However, one study showed a correlation of size of subchorionic hemorrhage, age of patient, and time of bleeding with the likelihood of spontaneous abortion. Women who were over 35 years of age and had large bleeds before 8 weeks were most likely to spontaneously abort.
Ectopic pregnancy must be considered if a gestational sac is absent when the beta hCG level exceeds the discriminatory level for detecting a sac (especially if significant vaginal bleeding has not occurred), or historically, by 4 to 5 weeks gestational age. At least one investigator concludes that in patients with suspected ectopic pregnancy, vaginal sonography can and should be used alone for these examinations.
The role of Doppler ultrasound for evaluating patients with first trimester bleeding remains unclear. In the experience of some investigators, measuring the Resistive Index (RI) to evaluate uteroplacental blood flow has proven effective for differentiating normal from abnormal intrauterine pregnancies; the findings of other investigators, however, have not been similar. Color and pulsed Doppler have also been advocated by some investigators to improve the sensitivity for diagnosing ectopic pregnancy; this too, is not universally accepted. Some clinical and sonographic predictors of ectopic pregnancy outcome include longer times from last menstrual period (LMP), lower beta hCG, absence of gestational sac, and higher resistive indexes. In women with possible gestational trophoblastic disease, Doppler of trophoblastic tissue reveals a low impedance, high-flow state that differs from the lower-flow, higher impedance pattern seen in women with nonviable gestations or degenerating fibroids. Doppler may prove to be especially useful to evaluate myometrial invasion and during follow-up examinations for women receiving chemotherapy.
Abbreviations
- BhCG, beta human chorionic gonadotropin
- CR, crown-rump
- CRL, crown-rump length
- D & C, dilation and curettage
- FHM, fetal heart movement
- MSD, mean sac diameters
- TA, transabdominal
- TV, transvaginal
- US, ultrasound