Transvaginal Ultrasound (TVS)

Transvaginal ultrasound (TVS) is the gold standard imaging for all fertility-specific assessments. Key uses: antral follicle count (ovarian reserve); baseline scan before IVF/IUI cycle start; follicle monitoring during stimulation; endometrial thickness and trilaminar pattern assessment; early pregnancy detection and viability (fetal heartbeat from 6 weeks); ectopic pregnancy assessment; detecting polyps, fibroids, and cysts that affect implantation.

Yes — completely safe. TVS uses diagnostic ultrasound (sound waves), not X-rays or radiation. No evidence of harm to eggs, embryos, or early pregnancy. The probe is covered with a sterile disposable sheath. It is performed routinely throughout IVF cycles — including in early pregnancy from 5–6 weeks. It causes no interference with the fertility treatment cycle and can be repeated daily if clinically required.

TVS (transvaginal sonography) = probe inserted into vagina (5–9 MHz, high resolution, empty bladder). Regular/transabdominal USS = probe on abdomen (3–5 MHz, lower resolution, full bladder needed). TVS provides 2–3x higher resolution at close range — essential for counting small follicles (2mm+), measuring endometrial pattern, and detecting small polyps. TVS is always preferred for fertility monitoring; transabdominal is used for larger structures (big fibroids, ovarian cysts >5cm, late-pregnancy scans).

Typically 4–6 transvaginal scans per IVF cycle: (1) Baseline scan Day 2–4 (AFC + no cysts check); (2) First stimulation check Day 5–6; (3) Second stimulation check Day 7–8; (4) Pre-trigger decision Day 9–11 (follicle sizes + E2); (5) Optional scan Day 2–3 post-trigger (corpus luteum confirmation); (6) Early pregnancy scan at 6–7 weeks post-transfer. Total: 5–6 scans across 4 weeks. Frequency increases if response is slow or if OHSS risk is present.

Yes — TVS can detect a gestational sac from approximately 4.5–5 weeks of pregnancy (2–3 weeks post-embryo transfer). Fetal cardiac activity is visible from 5 weeks 5 days to 6 weeks on TVS — approximately 1–2 weeks earlier than transabdominal ultrasound. In IVF patients, a TVS early pregnancy scan is routinely performed at 6–7 weeks gestation to confirm intrauterine location (exclude ectopic pregnancy), viability (heartbeat), and number of sacs (singleton vs twins).