Anesthesia Considerations for IVF 

In-vitro fertilization is an exciting technology that has allowed many couples struggling with infertility to conceive children³. These procedures consist of ovarian stimulation and monitoring, ultrasound-guided oocyte retrieval, and transfer of fertilized embryos back into the uterus³. Oocyte retrieval in particular is a significantly painful procedure that necessitates anesthesia. However, general anesthesia is suboptimal due to worse IVF outcomes from the stress of GA on the body³. Making sure the patient’s pain is well controlled is crucial to the success of the procedure ³.  

Oocyte-retrieval is a short, 20-30 minute procedure, usually conducted with an ultrasound-guided transvaginal probe in an outpatient setting, and thus requires a short-acting anesthetic with minimal postoperative sedation and other side-effects³. However, sometimes general anesthesia is the only clinically feasible option, and has been shown to relax the uterus enough for a more effective retrieval procedure. According to a review article in the Journal of Obstetric Anesthesia and Critical Care, the difficulty with many general anesthetic agents is that they have been found in follicular fluid, and thus they may have an adverse effect on fertilization and embryonic development³. If GA is being used, there needs to be an effort to use the lowest possible dose for the shortest possible duration³. In terms of safe pharmacological options, nitrous oxide has been shown to be safe when used with an isoflurane-based GA regimen, and short-acting opioids such as fentanyl and remifentanil also do not decrease the likelihood of IVF success³.  

Local anesthesia as a whole is preferable to general anesthesia, but there are many variables to consider, including choice and dosage of agent, method of administration, effects of combination with other drugs and length of exposure³. The most common form of anesthesia for oocyte retrieval procedures in the UK is monitored anesthesia under conscious sedation, which is used in 46% of IVF procedures. MAC is well-tolerated in ambulatory surgeries, technically simpler to administer, and has no reported adverse effects on oocytes³. According to a Cochrane Review, patients responded best to the combined use of a sedative and analgesic agent than either modality used alone, and choice of pharmacological agent is typically made through shared decision-making with the patient². Other options are regional, which can be done with a paracervical block, spinal, epidural, total intravenous and patient-controlled anesthesia³. These techniques were all shown by various studies to provide adequate pain control while also being associated with good reproductive outcomes³. One study did show that IV anesthesia was associated with longer recovery times and more episodes of post-operative emesis than spinal anesthesia, but it is still a viable alternative to GA³. The discussion of individual anesthetic agents is too complex for inclusion in this article, however, like type of anesthesia, it is a decision that involves shared decision-making between patient and clinician.  

Despite the significant pain involved in these procedures, there is a subset of patients who choose to undergo oocyte retrieval without any sedation or pain-control¹. One paper in the Society for Reproduction and Fertility discusses the reasons for this choice, and they include fear of anesthesia as well as higher anxiety scores than their peers¹. And while patients who choose no anesthesia experience more pain, almost all of them report that they would do it again, which is ultimately an acceptable choice that does not increase risk of morbidity or IVF failure¹. T 

References 

1. Bilbao S, Kimiagarov P, Noni A, Doran R, Seidman DS. Why do women choose to undergo oocyte aspiration without sedation or analgesia? Reproduction and Fertility, 2021; 2(2): 89-94. DOI: 10.1530/RAF-20-0063. 

2. Kwan I, Wang R, Pearce E, Bhattacharya S. Pain relief for women undergoing oocyte retrieval for assisted reproduction. Cochran Database of Systematic Reviews, 2018; 5. DOI: 10.1002/14651858 

3. Sharma A, Borle A, Trikha A. Anesthesia for in vitro fertilization-Review Article. Journal of Obstetric Anaesthesia and Critical Care, 2015; 5(2): 62-72. DOI: 10.4103/2249-4472.165132