From the Guidelines
Ultrasound is the primary imaging modality for evaluating vaginal bleeding in pregnancy, particularly in the second and third trimesters, as it is safe and effective in diagnosing potential causes of bleeding, such as placenta previa, vasa previa, and placental abruption 1.
Importance of Ultrasound in Pregnancy
Ultrasound examinations are crucial throughout pregnancy to monitor fetal development and maternal health. The standard schedule includes a first-trimester ultrasound to confirm pregnancy viability, establish gestational age, and check for multiple pregnancies.
Ultrasound Techniques
Transabdominal ultrasound is the mainstay of obstetrical imaging, but transvaginal ultrasound is particularly helpful in evaluating cervical-related causes of vaginal bleeding, as it provides more accurate and detailed images of the cervix and placenta 1.
Safety and Effectiveness
Ultrasound imaging uses sound waves rather than radiation, making it safe for both mother and baby. The technology works by sending high-frequency sound waves through the abdomen that bounce off the fetus, creating images of the developing baby.
Recommendations
- Transvaginal ultrasound is recommended for evaluating vaginal bleeding in the second and third trimesters, especially when cervical-related causes are suspected 1.
- Patients should arrive with a moderately full bladder for first-trimester abdominal ultrasounds to improve image quality, though this isn't necessary for later scans or transvaginal ultrasounds.
- Additional ultrasounds may be performed in the third trimester to monitor growth, placental position, and amniotic fluid levels, particularly in high-risk pregnancies 1.
From the Research
Ultrasound Pregnancy
- Ultrasound can provide important and potentially life-saving information for the emergency physician evaluating a patient with an obstetric emergency 2
- There are two possible approaches to ultrasound in pregnancy: transabdominal and transvaginal 2
- Understanding developmental anatomy, which changes during pregnancy, is important for ultrasound in pregnant patients 2
- Two basic yet important uses of ultrasound in pregnant patients are to determine gestational age and fetal heart rate 2
- Ultrasound plays a major role in diagnosing and managing suspected ectopic pregnancy 2
Imaging Findings in Pregnancy
- Placental abruption is a significant cause of feto-maternal hemorrhage, and imaging studies like ultrasound and MRI can help evaluate abdominal pain in pregnancy 3
- Concealed intra-amniotic hemorrhage may present with markedly echogenic amniotic fluid on ultrasound and varying signal intensity on MRI depending on the duration of bleeding 3
Non-Relevant Studies
- There are studies unrelated to ultrasound pregnancy, such as the effect of temperature on goldfish optic nerve regeneration 4, which do not provide relevant information on this topic.