Normal First Trimester Ultrasound Report Template

Normal first trimester OB ultrasound report template: live intrauterine pregnancy, CRL with gestational age, cardiac activity, adnexa and free fluid.

EXAMINATION: First trimester obstetric ultrasound, transabdominal
and transvaginal.

CLINICAL HISTORY: [indication]. LMP: [date].

COMPARISON: None available.

TECHNIQUE: Real-time grayscale transabdominal and transvaginal imaging
of the pelvis. M-mode documentation of embryonic cardiac activity.

FINDINGS:
Uterus: Normal in size and contour. A single intrauterine gestational
sac is present, with a yolk sac.
Embryo: A single embryo is identified. Crown-rump length [x] cm,
corresponding to a gestational age of [x] weeks [x] days.
Cardiac activity: Present, at [x] beats per minute by M-mode.
Right ovary: Unremarkable. Corpus luteum [present/not identified].
Left ovary: Unremarkable.
Adnexa: No adnexal mass.
Free fluid: No significant free pelvic fluid.

IMPRESSION:
1. Single live intrauterine pregnancy.
2. Gestational age [x] weeks [x] days by crown-rump length; estimated
due date [date].

Dictation notes

• Document cardiac activity with M-mode, not spectral Doppler — pulsed Doppler on an embryo is an ALARA violation most departments prohibit in the first trimester.
• Absent cardiac activity is diagnostic of failed pregnancy only at CRL of 7 mm or more; below that, the SRU criteria demand follow-up, not a verdict.
• An IUP does not fully exclude ectopic in an IVF patient — heterotopic pregnancy wording belongs in that context.

Frequently asked questions

What does a normal first trimester ultrasound report include?

A normal first trimester report documents a single intrauterine gestational sac with a yolk sac, an embryo with crown-rump length and the corresponding gestational age, cardiac activity with a rate documented by M-mode, both ovaries including any corpus luteum, the adnexa, and pelvic free fluid. The impression states a single live intrauterine pregnancy with the gestational age and estimated due date by crown-rump length.

Why is M-mode used instead of Doppler for embryonic heart rate?

Embryonic cardiac activity should be documented with M-mode, not spectral or pulsed Doppler. Doppler delivers substantially higher acoustic energy to the embryo, which violates the ALARA (as-low-as-reasonably-achievable) principle during organogenesis, and most departments prohibit pulsed Doppler on a first trimester embryo for that reason. M-mode documents both the presence of cardiac activity and the rate at much lower exposure.

When is absent cardiac activity diagnostic of pregnancy failure?

By the Society of Radiologists in Ultrasound criteria, absent cardiac activity is diagnostic of failed pregnancy only when the crown-rump length is 7 mm or more. Below that threshold the finding demands follow-up imaging, not a verdict — a normal early embryo may simply be too young to show detectable cardiac activity. Separately, an intrauterine pregnancy does not fully exclude ectopic in an IVF patient, where heterotopic pregnancy remains possible.

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