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What role does diagnostic office hysteroscopy play in an infertility evaluation?
.1
More specifically, hysteroscopy is the gold standard for assessing the uterine cavity. The sensitivity, specificity, and positive predictive and negative predictive values of hysterosalpingography (HSG) in evaluating uterine cavity abnormalities were 44.83%; 86.67%; 56.52%; and 80.25%, respectively.2 Given the poor sensitivity of HSG, a diagnosis of endometrial polyps and/or chronic endometritis is more likely to be missed.
Our crossover trial comparing HSG to office hysteroscopy for tubal patency showed that women were 110 times more likely to have the maximum level of pain with HSG than diagnostic hysteroscopy when using a 2.8-mm flexible hysteroscope.3 Further, infection rates and vasovagal events were far lower with hysteroscopy.1
Finally, compared with HSG, we showed 98%-100% sensitivity and 84% specificity for tubal occlusion with hysteroscopy by air-infused saline. Conversely, HSG typically is associated with 76%-96% sensitivity and 67%-100% specificity.4 Additionally, we can often perform diagnostic hysteroscopies for approximately $35 per procedure for total fixed and disposable equipment costs.
How should physicians perform office hysteroscopy to minimize patient discomfort?
The classic paradigm has been to focus on paracervical blocks, anxiolytics, and a supportive environment (such as mood music). However, those are far more important when your hysteroscope is larger than the natural cervical lumen. If you can use small hysteroscopes (< 3 mm for the nulliparous cervix, < 4 mm for the parous cervix), most women will not require cervical dilation, which further enhances the patient experience.
Using a flexible hysteroscope for suspected pathology, making sure not to overdistend the uterus (particularly in high-risk patients such as those with tubal occlusion and cervical stenosis), and vaginoscopy can all minimize patient discomfort. We have published data showing that by using a 2.8-mm flexible diagnostic hysteroscope in a group of mostly nulliparous women, greater than 50% have no discomfort, and more than 90% will have mild to no discomfort.3
What operative hysteroscopy procedures can be performed safely in a physician’s office, and what equipment is required?
Though highly dependent on experience and resources, reproductive endocrinology and infertility specialists (REIs) arguably have the easiest transition to operative office hysteroscopy by utilizing the analgesia and procedure room that is standard for oocyte retrieval and simply adding hysteroscopic procedures. The accompanying table stratifies general hysteroscopic procedures by difficulty.
If one can use propofol or a similar level of sedation (which is routinely utilized for oocyte aspiration), there are few hysteroscopies that cannot be accomplished in the office. However, the less sedation and analgesia, the more judicious one must be in patient selection. Moreover, there are trade-offs between visualization, comfort, and instrumentation.
The greater the uterine distention and diameter of the hysteroscope, the more patients experience pain. One-third of patients (especially nulliparous) will discontinue a procedure with a 5-mm hysteroscope because of discomfort.5 However, as one drops to 4.5 mm and smaller operative hysteroscopes, instruments often occupy the inflow channel, limiting distention and visualization, which also can affect completion rates and safety.
When is operative hysteroscopy best suited for the OR?
In addition to physician experience and clinical resources, the critical factors guiding our choices for selecting the OR rather than the office, include:
- Loss of landmarks. Though Dr. Parry now does most severe intrauterine adhesion cases in the office with ultrasound guidance, when neither ostia can be visualized there is meaningful risk for perforation. Preoperative estrogen, development of planes with the diagnostic hysteroscope prior, and preparing the patient for a possible multistage procedure are all important.
- Use of energy. There are many excellent hysteroscopic surgeons who use the resectoscope well in the office. However, with possible patient movement and potential perforation with energy leading to a bowel injury, there can be greater risk when using energy relative to other methods (such as forceps, scissors, and mechanical morcellation).
- Deeper fibroids. Fibroids displace rather than invade the myometrium, and one can sonographically visualize the myometrium reapproximate over a fibroid as it herniates more into the uterine cavity. Nevertheless, the closer a fibroid comes to the serosa, the more mindful one should be of risks and balances for hysteroscopic removal.
In a patient with a severely stenotic cervix or tortuous endocervical canal, what preprocedure methods do you find helpful, and do you utilize abdominal ultrasound guidance?
If using a 2.8-mm flexible diagnostic hysteroscope, we find 99.8%-99.9% of cervices can be successfully cannulated in the office, with rare exception, that is, following cryotherapy or chlamydia cervicitis. This is the equivalent of your dilator having a camera on the tip and fully articulating to adjust to the cervical path.
Transvaginal sonography prior to hysteroscopy where one maps the cervical lumen helps anticipate problems (along with being familiar with the patient’s history). For the rare dilation under anesthesia, concurrent sonography with a 2.8-mm flexible hysteroscope and intermittent dilator use has been sufficient for our exceptions without the need for lacrimal dilators, vasopressin, misoprostol, and other adjuncts. Of note, we use a 1080p flexible endoscope, as lower resolution would make this more challenging.
In patients with recurrent implantation failure following IVF, is hysteroscopy superior to 3D saline infusion sonogram?
At an American Society of Reproductive Medicine 2021 session, Ilan Tur-Kaspa, MD, and Dr. Parry debated the topic of 2D ultrasound combined with hysteroscopy vs. 3D saline infusion sonography. Core areas of agreement were that expert hands for any approach are better than nonexpert, and high-resolution technology is better than lower resolution. There was also agreement that extrauterine and myometrial disease, such as intramural fibroids and adenomyosis, are contributory factors.
So, sonography will always have a role. However, existing and forthcoming data show hysteroscopy to improve live birth rates for patients with recurrent implantation failure after IVF. Dr. Parry finds diagnostic hysteroscopy easier for identifying endometritis, sessile and cornual polyps, retained products of conception (which are often isoechogenic with the endometrium) and lateral adhesions.
The reality is that there is variability among physicians and midlevel providers in both sonographic and diagnostic hysteroscopic skill. If one wants to verify findings with another team member, acknowledging that there can be nuances to identifying these pathologies by sonography, it is easier to share and discuss findings through hysteroscopic video than sonographic records.
When is endometrial biopsy indicated during office hysteroscopy?
The patients of an REI are very unlikely to have endometrial cancer (or even hyperplasia) outside of polyps (or arguably hypervascular areas of overgrowth), so the focus is on resecting visualized pathology relative to random biopsy.
However, the threshold for biopsy should be adjusted to the patient population, as well as to individual findings and risk. RVUs are greatly increased (11.1 > 41.57) with biopsy, helping sustainability. Additionally, if one places the hysteroscope on endometrium and applies suction through the inflow channel, one can obtain a sample with small-caliber diagnostic hysteroscopes and without having to use forceps.
What is your threshold for fluid deficit in hysteroscopy?
We follow AAGL guidelines, which for operative hysteroscopy are 2,500 mL of isotonic fluids or 1,000 mL of hypotonic fluids in low-risk patients. This should be further reduced to 500 mL of isotonic fluids in the elderly and even 300 mL in those with cardiovascular compromise.6
For patients who request sedation for office hysteroscopy, which option do you recommend – paracervical block alone, nitrous oxide, or the combination?
For diagnostic, greater than 95% of our patients do not require even over-the-counter analgesic medications. For operative, we consider all permissible resources that allow for a safe combination that is appropriate to the pathology and clinical setting, such as paracervical blocks, nitrous oxide, NSAIDs such as ketorolac, anxiolytics, and more.
The goal is to optimize the patient experience. However, the top three criteria that influence successful operative office hysteroscopy for a conscious patient are a parous cervix, judicious patient selection, and pre- and intraoperative verbal analgesia. Informed consent and engagement improve the experience of both the patient and physician.
Dr. Parry is the founder of Positive Steps Fertility in Madison, Miss. Dr. Trolice is director of The IVF Center in Winter Park, Fla., and professor of obstetrics and gynecology at the University of Central Florida, Orlando.
References
1. Parry JP et al. J Minim Invasive Gynecol. 2017 May-Jun. doi: 10.1016/j.jmig.2017.02.010.
2. Wadhwa L et al. 2017 Apr-Jun. doi: 10.4103/jhrs.JHRS_123_16.
3. Parry JP et al. Fertil Steril. 2017 Oct. doi: 10.1016/j.fertnstert.2017.07.1159.
4. Penzias A et al. Fertil Steril. 2021 Nov. doi: 10.1016/j.fertnstert.2021.08.038.
5. Campo R et al. Hum Reprod. 2005 Jan;20(1):258-63. doi: 10.1093/humrep/deh559.
6. AAGL AAGL practice report: Practice guidelines for the management of hysteroscopic distending media. J Minim Invasive Gynecol. 2013 Mar-Apr. doi: 10.1016/j.jmig.2012.12.002.
What role does diagnostic office hysteroscopy play in an infertility evaluation?
.1
More specifically, hysteroscopy is the gold standard for assessing the uterine cavity. The sensitivity, specificity, and positive predictive and negative predictive values of hysterosalpingography (HSG) in evaluating uterine cavity abnormalities were 44.83%; 86.67%; 56.52%; and 80.25%, respectively.2 Given the poor sensitivity of HSG, a diagnosis of endometrial polyps and/or chronic endometritis is more likely to be missed.
Our crossover trial comparing HSG to office hysteroscopy for tubal patency showed that women were 110 times more likely to have the maximum level of pain with HSG than diagnostic hysteroscopy when using a 2.8-mm flexible hysteroscope.3 Further, infection rates and vasovagal events were far lower with hysteroscopy.1
Finally, compared with HSG, we showed 98%-100% sensitivity and 84% specificity for tubal occlusion with hysteroscopy by air-infused saline. Conversely, HSG typically is associated with 76%-96% sensitivity and 67%-100% specificity.4 Additionally, we can often perform diagnostic hysteroscopies for approximately $35 per procedure for total fixed and disposable equipment costs.
How should physicians perform office hysteroscopy to minimize patient discomfort?
The classic paradigm has been to focus on paracervical blocks, anxiolytics, and a supportive environment (such as mood music). However, those are far more important when your hysteroscope is larger than the natural cervical lumen. If you can use small hysteroscopes (< 3 mm for the nulliparous cervix, < 4 mm for the parous cervix), most women will not require cervical dilation, which further enhances the patient experience.
Using a flexible hysteroscope for suspected pathology, making sure not to overdistend the uterus (particularly in high-risk patients such as those with tubal occlusion and cervical stenosis), and vaginoscopy can all minimize patient discomfort. We have published data showing that by using a 2.8-mm flexible diagnostic hysteroscope in a group of mostly nulliparous women, greater than 50% have no discomfort, and more than 90% will have mild to no discomfort.3
What operative hysteroscopy procedures can be performed safely in a physician’s office, and what equipment is required?
Though highly dependent on experience and resources, reproductive endocrinology and infertility specialists (REIs) arguably have the easiest transition to operative office hysteroscopy by utilizing the analgesia and procedure room that is standard for oocyte retrieval and simply adding hysteroscopic procedures. The accompanying table stratifies general hysteroscopic procedures by difficulty.
If one can use propofol or a similar level of sedation (which is routinely utilized for oocyte aspiration), there are few hysteroscopies that cannot be accomplished in the office. However, the less sedation and analgesia, the more judicious one must be in patient selection. Moreover, there are trade-offs between visualization, comfort, and instrumentation.
The greater the uterine distention and diameter of the hysteroscope, the more patients experience pain. One-third of patients (especially nulliparous) will discontinue a procedure with a 5-mm hysteroscope because of discomfort.5 However, as one drops to 4.5 mm and smaller operative hysteroscopes, instruments often occupy the inflow channel, limiting distention and visualization, which also can affect completion rates and safety.
When is operative hysteroscopy best suited for the OR?
In addition to physician experience and clinical resources, the critical factors guiding our choices for selecting the OR rather than the office, include:
- Loss of landmarks. Though Dr. Parry now does most severe intrauterine adhesion cases in the office with ultrasound guidance, when neither ostia can be visualized there is meaningful risk for perforation. Preoperative estrogen, development of planes with the diagnostic hysteroscope prior, and preparing the patient for a possible multistage procedure are all important.
- Use of energy. There are many excellent hysteroscopic surgeons who use the resectoscope well in the office. However, with possible patient movement and potential perforation with energy leading to a bowel injury, there can be greater risk when using energy relative to other methods (such as forceps, scissors, and mechanical morcellation).
- Deeper fibroids. Fibroids displace rather than invade the myometrium, and one can sonographically visualize the myometrium reapproximate over a fibroid as it herniates more into the uterine cavity. Nevertheless, the closer a fibroid comes to the serosa, the more mindful one should be of risks and balances for hysteroscopic removal.
In a patient with a severely stenotic cervix or tortuous endocervical canal, what preprocedure methods do you find helpful, and do you utilize abdominal ultrasound guidance?
If using a 2.8-mm flexible diagnostic hysteroscope, we find 99.8%-99.9% of cervices can be successfully cannulated in the office, with rare exception, that is, following cryotherapy or chlamydia cervicitis. This is the equivalent of your dilator having a camera on the tip and fully articulating to adjust to the cervical path.
Transvaginal sonography prior to hysteroscopy where one maps the cervical lumen helps anticipate problems (along with being familiar with the patient’s history). For the rare dilation under anesthesia, concurrent sonography with a 2.8-mm flexible hysteroscope and intermittent dilator use has been sufficient for our exceptions without the need for lacrimal dilators, vasopressin, misoprostol, and other adjuncts. Of note, we use a 1080p flexible endoscope, as lower resolution would make this more challenging.
In patients with recurrent implantation failure following IVF, is hysteroscopy superior to 3D saline infusion sonogram?
At an American Society of Reproductive Medicine 2021 session, Ilan Tur-Kaspa, MD, and Dr. Parry debated the topic of 2D ultrasound combined with hysteroscopy vs. 3D saline infusion sonography. Core areas of agreement were that expert hands for any approach are better than nonexpert, and high-resolution technology is better than lower resolution. There was also agreement that extrauterine and myometrial disease, such as intramural fibroids and adenomyosis, are contributory factors.
So, sonography will always have a role. However, existing and forthcoming data show hysteroscopy to improve live birth rates for patients with recurrent implantation failure after IVF. Dr. Parry finds diagnostic hysteroscopy easier for identifying endometritis, sessile and cornual polyps, retained products of conception (which are often isoechogenic with the endometrium) and lateral adhesions.
The reality is that there is variability among physicians and midlevel providers in both sonographic and diagnostic hysteroscopic skill. If one wants to verify findings with another team member, acknowledging that there can be nuances to identifying these pathologies by sonography, it is easier to share and discuss findings through hysteroscopic video than sonographic records.
When is endometrial biopsy indicated during office hysteroscopy?
The patients of an REI are very unlikely to have endometrial cancer (or even hyperplasia) outside of polyps (or arguably hypervascular areas of overgrowth), so the focus is on resecting visualized pathology relative to random biopsy.
However, the threshold for biopsy should be adjusted to the patient population, as well as to individual findings and risk. RVUs are greatly increased (11.1 > 41.57) with biopsy, helping sustainability. Additionally, if one places the hysteroscope on endometrium and applies suction through the inflow channel, one can obtain a sample with small-caliber diagnostic hysteroscopes and without having to use forceps.
What is your threshold for fluid deficit in hysteroscopy?
We follow AAGL guidelines, which for operative hysteroscopy are 2,500 mL of isotonic fluids or 1,000 mL of hypotonic fluids in low-risk patients. This should be further reduced to 500 mL of isotonic fluids in the elderly and even 300 mL in those with cardiovascular compromise.6
For patients who request sedation for office hysteroscopy, which option do you recommend – paracervical block alone, nitrous oxide, or the combination?
For diagnostic, greater than 95% of our patients do not require even over-the-counter analgesic medications. For operative, we consider all permissible resources that allow for a safe combination that is appropriate to the pathology and clinical setting, such as paracervical blocks, nitrous oxide, NSAIDs such as ketorolac, anxiolytics, and more.
The goal is to optimize the patient experience. However, the top three criteria that influence successful operative office hysteroscopy for a conscious patient are a parous cervix, judicious patient selection, and pre- and intraoperative verbal analgesia. Informed consent and engagement improve the experience of both the patient and physician.
Dr. Parry is the founder of Positive Steps Fertility in Madison, Miss. Dr. Trolice is director of The IVF Center in Winter Park, Fla., and professor of obstetrics and gynecology at the University of Central Florida, Orlando.
References
1. Parry JP et al. J Minim Invasive Gynecol. 2017 May-Jun. doi: 10.1016/j.jmig.2017.02.010.
2. Wadhwa L et al. 2017 Apr-Jun. doi: 10.4103/jhrs.JHRS_123_16.
3. Parry JP et al. Fertil Steril. 2017 Oct. doi: 10.1016/j.fertnstert.2017.07.1159.
4. Penzias A et al. Fertil Steril. 2021 Nov. doi: 10.1016/j.fertnstert.2021.08.038.
5. Campo R et al. Hum Reprod. 2005 Jan;20(1):258-63. doi: 10.1093/humrep/deh559.
6. AAGL AAGL practice report: Practice guidelines for the management of hysteroscopic distending media. J Minim Invasive Gynecol. 2013 Mar-Apr. doi: 10.1016/j.jmig.2012.12.002.
What role does diagnostic office hysteroscopy play in an infertility evaluation?
.1
More specifically, hysteroscopy is the gold standard for assessing the uterine cavity. The sensitivity, specificity, and positive predictive and negative predictive values of hysterosalpingography (HSG) in evaluating uterine cavity abnormalities were 44.83%; 86.67%; 56.52%; and 80.25%, respectively.2 Given the poor sensitivity of HSG, a diagnosis of endometrial polyps and/or chronic endometritis is more likely to be missed.
Our crossover trial comparing HSG to office hysteroscopy for tubal patency showed that women were 110 times more likely to have the maximum level of pain with HSG than diagnostic hysteroscopy when using a 2.8-mm flexible hysteroscope.3 Further, infection rates and vasovagal events were far lower with hysteroscopy.1
Finally, compared with HSG, we showed 98%-100% sensitivity and 84% specificity for tubal occlusion with hysteroscopy by air-infused saline. Conversely, HSG typically is associated with 76%-96% sensitivity and 67%-100% specificity.4 Additionally, we can often perform diagnostic hysteroscopies for approximately $35 per procedure for total fixed and disposable equipment costs.
How should physicians perform office hysteroscopy to minimize patient discomfort?
The classic paradigm has been to focus on paracervical blocks, anxiolytics, and a supportive environment (such as mood music). However, those are far more important when your hysteroscope is larger than the natural cervical lumen. If you can use small hysteroscopes (< 3 mm for the nulliparous cervix, < 4 mm for the parous cervix), most women will not require cervical dilation, which further enhances the patient experience.
Using a flexible hysteroscope for suspected pathology, making sure not to overdistend the uterus (particularly in high-risk patients such as those with tubal occlusion and cervical stenosis), and vaginoscopy can all minimize patient discomfort. We have published data showing that by using a 2.8-mm flexible diagnostic hysteroscope in a group of mostly nulliparous women, greater than 50% have no discomfort, and more than 90% will have mild to no discomfort.3
What operative hysteroscopy procedures can be performed safely in a physician’s office, and what equipment is required?
Though highly dependent on experience and resources, reproductive endocrinology and infertility specialists (REIs) arguably have the easiest transition to operative office hysteroscopy by utilizing the analgesia and procedure room that is standard for oocyte retrieval and simply adding hysteroscopic procedures. The accompanying table stratifies general hysteroscopic procedures by difficulty.
If one can use propofol or a similar level of sedation (which is routinely utilized for oocyte aspiration), there are few hysteroscopies that cannot be accomplished in the office. However, the less sedation and analgesia, the more judicious one must be in patient selection. Moreover, there are trade-offs between visualization, comfort, and instrumentation.
The greater the uterine distention and diameter of the hysteroscope, the more patients experience pain. One-third of patients (especially nulliparous) will discontinue a procedure with a 5-mm hysteroscope because of discomfort.5 However, as one drops to 4.5 mm and smaller operative hysteroscopes, instruments often occupy the inflow channel, limiting distention and visualization, which also can affect completion rates and safety.
When is operative hysteroscopy best suited for the OR?
In addition to physician experience and clinical resources, the critical factors guiding our choices for selecting the OR rather than the office, include:
- Loss of landmarks. Though Dr. Parry now does most severe intrauterine adhesion cases in the office with ultrasound guidance, when neither ostia can be visualized there is meaningful risk for perforation. Preoperative estrogen, development of planes with the diagnostic hysteroscope prior, and preparing the patient for a possible multistage procedure are all important.
- Use of energy. There are many excellent hysteroscopic surgeons who use the resectoscope well in the office. However, with possible patient movement and potential perforation with energy leading to a bowel injury, there can be greater risk when using energy relative to other methods (such as forceps, scissors, and mechanical morcellation).
- Deeper fibroids. Fibroids displace rather than invade the myometrium, and one can sonographically visualize the myometrium reapproximate over a fibroid as it herniates more into the uterine cavity. Nevertheless, the closer a fibroid comes to the serosa, the more mindful one should be of risks and balances for hysteroscopic removal.
In a patient with a severely stenotic cervix or tortuous endocervical canal, what preprocedure methods do you find helpful, and do you utilize abdominal ultrasound guidance?
If using a 2.8-mm flexible diagnostic hysteroscope, we find 99.8%-99.9% of cervices can be successfully cannulated in the office, with rare exception, that is, following cryotherapy or chlamydia cervicitis. This is the equivalent of your dilator having a camera on the tip and fully articulating to adjust to the cervical path.
Transvaginal sonography prior to hysteroscopy where one maps the cervical lumen helps anticipate problems (along with being familiar with the patient’s history). For the rare dilation under anesthesia, concurrent sonography with a 2.8-mm flexible hysteroscope and intermittent dilator use has been sufficient for our exceptions without the need for lacrimal dilators, vasopressin, misoprostol, and other adjuncts. Of note, we use a 1080p flexible endoscope, as lower resolution would make this more challenging.
In patients with recurrent implantation failure following IVF, is hysteroscopy superior to 3D saline infusion sonogram?
At an American Society of Reproductive Medicine 2021 session, Ilan Tur-Kaspa, MD, and Dr. Parry debated the topic of 2D ultrasound combined with hysteroscopy vs. 3D saline infusion sonography. Core areas of agreement were that expert hands for any approach are better than nonexpert, and high-resolution technology is better than lower resolution. There was also agreement that extrauterine and myometrial disease, such as intramural fibroids and adenomyosis, are contributory factors.
So, sonography will always have a role. However, existing and forthcoming data show hysteroscopy to improve live birth rates for patients with recurrent implantation failure after IVF. Dr. Parry finds diagnostic hysteroscopy easier for identifying endometritis, sessile and cornual polyps, retained products of conception (which are often isoechogenic with the endometrium) and lateral adhesions.
The reality is that there is variability among physicians and midlevel providers in both sonographic and diagnostic hysteroscopic skill. If one wants to verify findings with another team member, acknowledging that there can be nuances to identifying these pathologies by sonography, it is easier to share and discuss findings through hysteroscopic video than sonographic records.
When is endometrial biopsy indicated during office hysteroscopy?
The patients of an REI are very unlikely to have endometrial cancer (or even hyperplasia) outside of polyps (or arguably hypervascular areas of overgrowth), so the focus is on resecting visualized pathology relative to random biopsy.
However, the threshold for biopsy should be adjusted to the patient population, as well as to individual findings and risk. RVUs are greatly increased (11.1 > 41.57) with biopsy, helping sustainability. Additionally, if one places the hysteroscope on endometrium and applies suction through the inflow channel, one can obtain a sample with small-caliber diagnostic hysteroscopes and without having to use forceps.
What is your threshold for fluid deficit in hysteroscopy?
We follow AAGL guidelines, which for operative hysteroscopy are 2,500 mL of isotonic fluids or 1,000 mL of hypotonic fluids in low-risk patients. This should be further reduced to 500 mL of isotonic fluids in the elderly and even 300 mL in those with cardiovascular compromise.6
For patients who request sedation for office hysteroscopy, which option do you recommend – paracervical block alone, nitrous oxide, or the combination?
For diagnostic, greater than 95% of our patients do not require even over-the-counter analgesic medications. For operative, we consider all permissible resources that allow for a safe combination that is appropriate to the pathology and clinical setting, such as paracervical blocks, nitrous oxide, NSAIDs such as ketorolac, anxiolytics, and more.
The goal is to optimize the patient experience. However, the top three criteria that influence successful operative office hysteroscopy for a conscious patient are a parous cervix, judicious patient selection, and pre- and intraoperative verbal analgesia. Informed consent and engagement improve the experience of both the patient and physician.
Dr. Parry is the founder of Positive Steps Fertility in Madison, Miss. Dr. Trolice is director of The IVF Center in Winter Park, Fla., and professor of obstetrics and gynecology at the University of Central Florida, Orlando.
References
1. Parry JP et al. J Minim Invasive Gynecol. 2017 May-Jun. doi: 10.1016/j.jmig.2017.02.010.
2. Wadhwa L et al. 2017 Apr-Jun. doi: 10.4103/jhrs.JHRS_123_16.
3. Parry JP et al. Fertil Steril. 2017 Oct. doi: 10.1016/j.fertnstert.2017.07.1159.
4. Penzias A et al. Fertil Steril. 2021 Nov. doi: 10.1016/j.fertnstert.2021.08.038.
5. Campo R et al. Hum Reprod. 2005 Jan;20(1):258-63. doi: 10.1093/humrep/deh559.
6. AAGL AAGL practice report: Practice guidelines for the management of hysteroscopic distending media. J Minim Invasive Gynecol. 2013 Mar-Apr. doi: 10.1016/j.jmig.2012.12.002.