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.
Under ultrasound guidance, the operator inserts a 16.5 gauge × 11.8″ (1.6 mm × 300 mm outer diameter) needle through the vaginal wall and into an ovarian follicle, taking care not to injure nearby organs and blood vessels. The other end of the needle is attached to a suction device. Once the follicle is entered, suction is carefully applied to aspirate follicular fluid containing cellular material, including the oocyte. The suction device must maintain a pressure of -140 mmHg (necessary to aspirate rapidly, but not enough to damage the follicles) and a temperature of approximately 37 °C. The follicular fluid is delivered to a technician in the IVF laboratory to identify and quantify the ova. Once the ovarian follicles have been aspirated on one ovary, the needle is withdrawn and the procedure is repeated on the other ovary. It is not unusual to remove 20 oocytes as patients are generally hyperstimulated in advance of this procedure. After completion, the needle is withdrawn, and hemostasis is achieved. The procedure usually lasts 10–20 minutes. Once the extraction is done, the sample is analyzed in the microscope to select and carry out the oocyte decumulation, a process where the granulosa cells surrounding the oocyte are removed.
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.
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]
Seminal fluid contains several proteins that interact with epithelial cells of the cervix and uterus, inducing active gestational immune tolerance. There are significantly improved outcomes when patients are exposed to seminal plasma around the time of oocyte retrieval, with statistical significance for clinical pregnancy, but not for ongoing pregnancy or live birth rates with the limited data available. [9]
TVOR is typically performed after ovarian hyperstimulation, where oocytes are pharmacologically stimulated to mature. When the ovarian follicles have reached a certain degree of development, induction of final oocyte maturation is performed, generally by an intramuscular or subcutaneous injection of human chorionic gonadotropin (hCG). [10] TVOR is typically performed 34–36 hours after hCG injection, when the eggs are fully mature but just prior to rupture of the follicles. [10] [11]
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.
Propofol-based anesthetic techniques result in significant concentrations of propofol in follicular fluid. As propofol has been shown to have deleterious effects on oocyte fertilization (in a mouse model), some authors have suggested that the dose of propofol administered during anesthesia should be limited, and also that the retrieved oocytes should be washed free of propofol. [14] Anecdotal evidence suggests that certain airborne chemical contaminants and particles, especially volatile organic compounds (VOC), may be toxic to and impair the growth and development of embryos if present in sufficient concentrations in the ambient atmosphere of an IVF incubator. [15] [16]
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]
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.
In vitro fertilisation (IVF) is a process of fertilisation where an egg is combined with sperm in vitro. The process involves monitoring and stimulating a woman's ovulatory process, removing an ovum or ova from their ovaries and letting a man's sperm fertilise them in a culture medium in a laboratory. After the fertilised egg (zygote) undergoes embryo culture for 2–6 days, it is transferred by catheter into the uterus, with the intention of establishing a successful pregnancy.
Ovulation is the release of eggs from the ovaries. In women, this event occurs when the ovarian follicles rupture and release the secondary oocyte ovarian cells. After ovulation, during the luteal phase, the egg will be available to be fertilized by sperm. In addition, the uterine lining (endometrium) is thickened to be able to receive a fertilized egg. If no conception occurs, the uterine lining as well as the egg will be shed during menstruation.
Oogenesis, ovogenesis, or oögenesis is the differentiation of the ovum into a cell competent to further develop when fertilized. It is developed from the primary oocyte by maturation. Oogenesis is initiated in the embryonic stage.
Ovarian hyperstimulation syndrome (OHSS) is a medical condition that can occur in some women who take fertility medication to stimulate egg growth, and in other women in very rare cases. Most cases are mild, but rarely the condition is severe and can lead to serious illness or death.
Anti-Müllerian hormone (AMH), also known as Müllerian-inhibiting hormone (MIH), is a glycoprotein hormone structurally related to inhibin and activin from the transforming growth factor beta superfamily, whose key roles are in growth differentiation and folliculogenesis. In humans, it is encoded by the AMH gene, on chromosome 19p13.3, while its receptor is encoded by the AMHR2 gene on chromosome 12.
Ovarian reserve is a term that is used to determine the capacity of the ovary to provide egg cells that are capable of fertilization resulting in a healthy and successful pregnancy. With advanced maternal age the number of egg cell that can be successfully recruited for a possible pregnancy declines, constituting a major factor in the inverse correlation between age and female fertility.
Ovulation induction is the stimulation of ovulation by medication. It is usually used in the sense of stimulation of the development of ovarian follicles to reverse anovulation or oligoovulation.
Oocyte cryopreservation is a procedure to preserve a woman's eggs (oocytes). This technique has been used to postpone pregnancy. When pregnancy is desired, the eggs can be thawed, fertilized, and transferred to the uterus as embryos. Several studies have shown that most infertility problems are due to germ cell deterioration related to aging. The procedure's success rate varies depending on the age of the woman, with the odds being higher in younger, adult women.
An antral or secondary follicle, also known as Graafian follicle and tertiary follicle, is an ovarian follicle during a certain latter stage of folliculogenesis.
Controlled ovarian hyperstimulation is a technique used in assisted reproduction involving the use of fertility medications to induce ovulation by multiple ovarian follicles. These multiple follicles can be taken out by oocyte retrieval for use in in vitro fertilisation (IVF), or be given time to ovulate, resulting in superovulation which is the ovulation of a larger-than-normal number of eggs, generally in the sense of at least two. When ovulated follicles are fertilised in vivo, whether by natural or artificial insemination, there is a very high risk of a multiple pregnancy.
In vitro maturation (IVM) is the technique of letting the contents of ovarian follicles and the oocytes inside mature in vitro. It can be offered to women with infertility problems, combined with In Vitro Fertilization (IVF), offering women pregnancy without ovarian stimulation.
Poor ovarian reserve is a condition of low fertility characterized by 1): low numbers of remaining oocytes in the ovaries or 2) possibly impaired preantral oocyte development or recruitment. Recent research suggests that premature ovarian aging and premature ovarian failure may represent a continuum of premature ovarian senescence. It is usually accompanied by high FSH levels.
Fertility preservation is the effort to help cancer patients retain their fertility, or ability to procreate. Research into how cancer, ageing and other health conditions effect reproductive health and preservation options are growing. Specifically sparked in part by the increase in the survival rate of cancer patients.
The Genetics & IVF Institute (GIVF) is an international provider of infertility and genetics services and products, and also engages in biomedical research in these fields. The Institute was founded in 1984 by Dr. Joseph D. Schulman and associates. GIVF headquarters are in Fairfax, VA, US, and its facilities include locations in Pennsylvania, Minnesota, California, and Texas in the United States, as well as in China, Mexico, and several other countries.
Ovarian drilling, also known as multiperforation or laparoscopic ovarian diathermy, is a surgical technique of puncturing the membranes surrounding the ovary with a laser beam or a surgical needle using minimally invasive laparoscopic procedures. It differs from ovarian wedge resection, which involves the cutting of tissue. Minimally invasive ovarian drilling procedures have replaced wedge resections. Ovarian drilling is preferred to wedge resection because cutting into the ovary can cause adhesions which may complicate postoperative outcomes. Ovarian drilling and ovarian wedge resection are treatment options to reduce the amount of androgen producing tissue in women with polycystic ovarian syndrome (PCOS). PCOS is the primary cause of anovulation, which results in female infertility. The induction of mono-ovulatory cycles can restore fertility.
Fertility testing is the process by which fertility is assessed, both generally and also to find the "fertile window" in the menstrual cycle. General health affects fertility, and STI testing is an important related field.
Induction of final maturation of oocytes is a procedure that is usually performed as part of controlled ovarian hyperstimulation to render the oocytes fully developed and thereby resulting in optimal pregnancy chances. It is basically a replacement for the luteinizing hormone (LH) surge whose effects include final maturation in natural menstrual cycles.
Gonadotropin surge-attenuating factor (GnSAF) is a nonsteroidal ovarian hormone produced by the granulosa cells of small antral ovarian follicles in females. GnSAF is involved in regulating the secretion of luteinizing hormone (LH) from the anterior pituitary and the ovarian cycle. During the early to mid-follicular phase of the ovarian cycle, GnSAF acts on the anterior pituitary to attenuate LH release, limiting the secretion of LH to only basal levels. At the transition between follicular and luteal phase, GnSAF bioactivity declines sufficiently to permit LH secretion above basal levels, resulting in the mid-cycle LH surge that initiates ovulation. In normally ovulating women, the LH surge only occurs when the oocyte is mature and ready for extrusion. GnSAF bioactivity is responsible for the synchronised, biphasic nature of LH secretion.
Ovarian follicle dominance is the process where one or more follicles are selected per cycle to ovulate.
Ovarian culture is an in-vitro process that allows for the investigation of the development, toxicology and pathology of the ovary. This technique can also be used to study possible applications of fertility treatments e.g. isolating oocytes from primordial ovarian follicles that could be used for fertilisation.