Introduction
Special investigations complement the clinical examination: they image the pelvis, sample tissue and look directly into the cavities.
Imaging
- Transvaginal ultrasound: first-line for the uterus and ovaries; endometrial thickness (postmenopausal > 4 mm needs sampling), fibroids, cysts (simple versus complex, IOTA rules), ectopic pregnancy, follicle tracking. Transabdominal for large masses or girls.
- Saline infusion sonography: polyps and submucous fibroids.
- Hysterosalpingography (HSG): contrast through the cervix under X-ray; shows the cavity and tubal patency (spill into the peritoneum). Done in the follicular phase (after menses, before ovulation); risk of infection (antibiotic cover). HyCoSy is the ultrasound alternative.
- MRI (fibroids, adenomyosis, cancer staging), CT (cancer staging), PET.
Cytology and tissue sampling
- Cervical cytology (Pap smear or liquid-based) and HPV testing: screening for cervical precancer.
- Colposcopy: magnified view of the cervix after acetic acid (abnormal epithelium turns white) and Lugol's iodine (normal glycogen-rich epithelium stains brown, abnormal stays pale, Schiller test); directed biopsy of the transformation zone.
- Endometrial biopsy (Pipelle) in outpatients.
- Dilatation and curettage (D&C), or fractional (separate) curettage: endocervical canal and uterine cavity sampled separately, for abnormal bleeding and to localise endometrial cancer. Now largely replaced by hysteroscopy with biopsy.
- Probe of the uterine cavity (uterine sound): length and direction of the cavity.
- Culdocentesis (puncture of the pouch of Douglas through the posterior fornix): blood in ectopic pregnancy, pus in abscess; now replaced by ultrasound.
- Tumour markers: CA-125 (ovarian epithelial), hCG, AFP, LDH (germ cell), inhibin (granulosa cell), CEA.