Most pregnant women have at least two or three pregnancy ultrasounds.
They are basic but more can be included to closely monitor embryonic development.
First trimester ultrasound:
A standard first trimester ultrasound is performed before 14 weeks and 0 days of gestation. It can be performed transabdominally, transvaginally, or transperineally. Includes an assessment of the presence, size, location, and number of gestational sac(s); and an evaluation of the gestational sacs.
Indications for a first trimester ultrasound include the following:
- To confirm an intrauterine pregnancy.
- To evaluate a suspected ectopic pregnancy.
- To assess vaginal bleeding.
- To assess pelvic pain.
- To estimate gestational age.
- To diagnose and evaluate multiple gestations.
- To confirm cardiac activity.
- Complement in chorionic villus sampling.
- Complement in embryo transfer.
- Complement in the location and/or extraction of an intrauterine device.
- To evaluate certain fetal abnormalities, such as anencephaly, in high-risk patients.
- To evaluate pelvic masses, maternal adnexal masses or anomalies.
- To detect fetal aneuploidy (nuchal translucency) when part of aneuploidy screening.
- To evaluate suspected hydatidiform mole.
Ultrasound of the second or third trimester:
A standard ultrasound in the second or third trimester involves an evaluation of the fetus, presentation and number, amniotic fluid volume, cardiac activity, position of the placenta, fetal biometry, and anatomic study.
Indications for a standard second or third trimester ultrasound include the following:
- Detection of fetal anomalies.
- Evaluation of the fetal anatomy.
- Gestational age estimation.
- Evaluation of fetal growth.
- Evaluation of vaginal bleeding
- Evaluation of cervical insufficiency.
- Assessment of abdominal and pelvic pain.
- Determination of fetal presentation.
- Evaluation of suspected multiple gestation.
- Adjunct to amniocentesis or other procedure.
- Evaluation of the discrepancy between uterine size and clinical dates.
- Evaluation of the pelvic mass.
- Exam for suspected hydatidiform mole.
- Adjunct to the placement of cervical cerclage.
- Evaluation of suspected ectopic pregnancy.
- Evaluation of suspected fetal death.
- Evaluation of suspected uterine abnormality.
- Evaluation of fetal well-being.
- Evaluation of suspected abnormalities in the amniotic fluid.
- Evaluation of suspected placental abruption.
- Attached to the external cephalic version.
- Evaluation of abnormal biochemical markers.
- Follow-up evaluation of a fetal anomaly.
- Follow-up evaluation of placental location for suspected placenta previa.
- Evaluation with a history of previous congenital anomaly.
- Assessment of fetal condition in late enrollees for antenatal care.
- Evaluation of findings that may increase the risk of aneuploidy.
El Dr. Daniel García, gynecologist and obstetrician at Ginefem, explains when it is recommended to do a prenatal ultrasound.