Transvaginal oocyte retrieval

Transvaginal oocyte retrieval (TVOR), also referred to as oocyte retrieval (OCR), is a technique used in in vitro fertilization (IVF) in order to remove oocytes from an ovary, enabling fertilization outside the body.^[1] Transvaginal oocyte retrieval is more properly referred to as transvaginal ovum retrieval when the oocytes have matured into ova, as is normally the case in IVF. It can be also performed for egg donation, oocyte cryopreservation and other assisted reproduction technology such as ICSI.

Procedure

Under

Initially performed using transabdominal ultrasonography, TVOR is currently performed with a transvaginal ultrasound transducer with an attached needle.^[2] TVOR is performed in an operating room or a physician's office, with the (female) subject in the lithotomy position. TVOR is usually performed under procedural sedation,^[3] general anesthesia,^[4] paracervical block,^[5] or sometimes spinal anesthesia.^[6] Local anesthesia is not typically used because local anesthetic agents interfere with follicular cleavage and the technique requires multiple needle punctures.^[7]

This technique must be done very delicately, without stimulating the uterus, so that contractions do not occur. Minimizing patient anxiety is desirable to favor efficacy.

Adjunctive procedures

Follicular flushing has not been found to increase pregnancy rates, nor result in an increase in oocyte yield. On the other hand, it requires a significantly longer operative time and more analgesia.^[8]

Injection of hCG as a trigger for ovulation confers a risk of ovarian hyperstimulation syndrome, especially in patients with polycystic ovary syndrome who have been hyperstimulated during previous assisted reproduction cycles.^[12]

Complications of TVOR include injury to pelvic organs, hemorrhage, and infection. Occurring more often in lean patients with polycystic ovary syndrome, ovarian hemorrhage after TVOR is a potentially catastrophic and not so rare complication.^[13] Additional complications may result from the administration of intravenous sedation or general anesthesia. These include asphyxia caused by airway obstruction, apnea, hypotension, and pulmonary aspiration of stomach contents.

Endometriosis seems to cause a challenge for TVOR that may have reflection on individual surgeon's performance rates for the procedure, independently from the diameter of a pre-existing ovarian endometrioma (OMA) or ovarian adhesions. Obesity is another factor that may present a challenge for the procedure.[17]

History

This technique was first developed by Pierre Dellenbach and colleagues in Strasbourg, France, and reported in 1984.^[18] Steptoe and Edwards used laparoscopy to recover oocytes when IVF was introduced, and laparoscopy was the major method of oocyte recovery until TVOR was introduced.

References