Transvaginal Ultrasound: Uses in Reproductive Health and Why It Doesn’t Confirm Pregnancy

Transvaginal ultrasound (TVUS) uses a high-frequency (5–9 MHz) probe inserted into the vagina to obtain high-resolution images of the uterus, ovaries, adnexa, and cul-de-sac.

Clinical Indications

• Early pregnancy assessment (viability, location, dating) – after positive hCG.
• Infertility workup (follicular monitoring, endometrial thickness).
• Gynecologic pathology: fibroids, adenomyosis, ovarian cysts, endometriomas, polyps.
• IUD localization.
• Postmenopausal bleeding evaluation.

Pregnancy Diagnosis

• TVUS visualizes intrauterine gestational sac (~5–6 weeks), yolk sac, fetal pole, cardiac activity.
• It does not “confirm pregnancy” by itself. Definitive diagnosis requires positive hCG (urine or serum) correlated with imaging findings.
• Pseudogestational sac, decidual cyst, or early failed pregnancy can mimic true sac.

Clinical pathway: hCG → TVUS for viability/location → serial hCG/TVUS if indeterminate.