Transvaginal ultrasound (TVS) can be used for early first trimester obstetric ultrasounds, evaluating complications in later pregnancy like placenta previa, assessing the fetal spine position, and evaluating the nuchal region before 14 weeks. It is also used to evaluate suspected ectopic pregnancies, monitor follicle development during fertility treatments, and monitor ovarian response during assisted reproductive technology cycles. The procedure involves first performing a transabdominal ultrasound with a full bladder, then emptying the bladder and inserting the transvaginal probe to obtain images of the cervix, uterus, ovaries, and surrounding structures in both the sagittal and coronal planes. Key anatomical structures like the uterus and ovaries are described in

1. Transvaginal US

2. TVS
Gynaecologic US
Earlt first trimester obstetric US
Obstetric complications later in pregnancy
E.g. Placenta previa
Fetal spine in breech
Evaluation of fetal intra..... in cephalic fetuses
Evaluation of nuchal region before 14w

3. TVS
Suspected ectopic pregnancy
Follicle monitoring
Monitoring of assisted reproductive technology
(ART)

4. Generally :
TAS with full bladder
then empty the bladder
Followed by TVS
Not to be done in virginal pt, no consent to
vaginal examination

6. Orientation of TV probe (manoeuvres)
Rotation 0 to 90 degrees about its longitudinal
axis from capital to coronal
Angled or pointed in any direction for plane of
section
Advance or withdraw

7. As a marker note the position of the urinary
bladder- angle of the bladder is consistent .... the
variable positions of the uterus and ovaries

10. 1st
manouvre
Sagittal
plane
Sweep
Then rotation in coronal plane from cervix to uterine
fundus

11. Sagittal plane:
Cervix, endocervical canal
Post cul de sac
Uterus and endometrium
Right ovary and adnexa
Left ovary and adnexa

12. Coronal plane:
Vagina
Cervix and post cul de sac
Uterine corpus and endometrium
Uterine fundus and endometrium
R ovary and L ovary and adnexa

13. Applying pressure on ant abd
wall for high ovary

14. The Uterus
Before menarche- ratio of uterus to cervix is half
Nulliparous women- corpus and cervix equal length
Multip- corpus is double the size
Size of uterus is variable in adults:
6-8.5cm in length in multips
Width - 3 -5 cm in nulliparous, 4-6cm in multips
AP diameter- 2-4cm in nulliparous, 3-6cm in multips

15. After menopause- atrophy
>5 years menopause:
3.5-7cm length
2-4 cm width
1.7- 3.3cm AP
Prepubertal uterus 2-4.4cm
Position is highly variable and changes with
varying degree of bladder and rectal distension

16. Muscular layers- 3 distinct layers
The endometrium: thickness
4-8mm proliferative phase
6-10mm periovulatory
7-14mm secretory phase
Post menopausal < 8mm
If the endometrium > 5mm in PMB--> investigate

19. The Ovaries
Ellipsoid
Location is variable

20. Recruitment of follicles:
TVS can pick up when follicle is 2mm
Day 5-7
Day 8-12 one or more dominant follicles are
seen

21. Rate of growth of dominant follicles:
2-3mm per day
To reach max mean diameter of approx.
20mm (range 16-28mm)
24 hrs before ovulation:
The granulosa layer separates from the theca
layer resulting in a hypoechoic ring