Abstract
The role of nurses conducting ultrasound in assisted conception cycle monitoring is to evaluate the endometrial thickness and document the size of each ovarian follicle present. Women should have undergone a formal diagnostic ultrasound prior to commencing a stimulation cycle; therefore any pathology present should have already been formally documented. However, if any pathology is identified on an assisted fertility cycle monitoring scan, it should be noted and brought to the attention of the treating doctor.
The role of nurses conducting ultrasound in assisted conception cycle monitoring is to evaluate the endometrial thickness and document the size of each ovarian follicle present. Women should have undergone a formal diagnostic ultrasound prior to commencing a stimulation cycle; therefore any pathology present should have already been formally documented. However, if any pathology is identified on an assisted fertility cycle monitoring scan, it should be noted and brought to the attention of the treating doctor.
The following images demonstrate the most common anomalies seen in a gynaecology study.
Leiomyomas or Uterine Fibroid
Fibroids are benign tumours arising from the myometrium. Fibroids are extremely common, with one study of American women estimating a cumulative incidence of fibroids of 70–80% in women by the age of 50 years, with racial variation in frequency (Baird et al., 2003). Uterine sarcoma is a rare malignant tumour with an ultrasound appearance similar to that of fibroids. A meta-analysis of epidemiological studies estimated an overall incidence uterine sarcoma of 2.94 per 1,000 women undergoing surgery for a mass that preoperatively had been presumed to a benign fibroid. When stratified by age, the authors estimated a sarcoma incidence of less than 1 case per 500 women aged less than 30 years at the time of their surgery, compared to 10.1 cases per 1,000 women aged 75–79 years undergoing surgery (Brohl et al., 2015).
Fibroids may be submucosal (>50% of the fibroid is within the endometrial cavity), intramural (the majority of the fibroid is contained within the myometrium) or subserosal (>50% of the fibroid is located outside of the uterine myometrium). FIGO (International Federation of Gynaecology and Obstetrics) has provided a more detailed classification of fibroids, categorising from 0 to 8 depending of their location: 0, pedunculated within the cavity; 1, submucosal with <50% intramural; 2, submucosal with ≥50% of the fibroid intramural; 3, intramural with contact with the endometrium; 4, fibroid is completely intramural; 5, subserosal with ≥50% intramural; 6, subserosal with <50% intramural; 7, pedunculated subserosal; 8, other, for example, cervical (Munro et al., 2011).
Symptoms caused by fibroids are largely dependent on the location of the fibroid(s). Subserosal or cavity-distorting intramural fibroids may cause a number of problems including heavy menses and reduced fertility. A randomised controlled study reported that the removal of subserosal or submucosal-intramural fibroids resulted in an increased pregnancy rate (Casini et al., 2006). Guidelines produced on behalf of the American Society for Reproductive Medicine (Practice Committee of the American Society for Reproductive Medicine, 2017) state that there is insufficient evidence that any particular fibroid size, number or location (excluding submucosal and cavity distorting intramural fibroids) result in a reduced likelihood of pregnancy or an increased risk of miscarriage. Subserosal and non-cavity-distorting intramural fibroids are less likely to be symptomatic unless they grow to a large size and cause pressure related symptoms such as urinary frequency and abdominal enlargement or discomfort.
Fibroids may appear homogeneous or heterogeneous on ultrasound. Transabdominal sonography may be required to assess very large fibroids. The kidneys are checked for evidence of obstruction.
Figure 4.1 Fibroid in postero-fundal location of uterus. Note the change in the uterine outline.
Figure 4.2 Subserous fibroid bulging outward causing the change in the uterine outline.
Figure 4.3 Sagittal view of the uterus with a subserous fibroid at the fundus. Note the distortion of the uterine outline.
Figure 4.4 Submucous fibroid causing distortion of the endometrium.
Figure 4.5 Submucous fibroid distorting the anterior endometrium.
Figure 4.6 Submucous fibroid distorting the posterior endometrium.
Figure 4.7 Small hypoechoic fibroid distorting the posterior endometrium. Free fluid noted in the pouch of Douglas.
Figure 4.8 Transverse view, showing two small fibroids impacting on the posterior endometrium.
Figure 4.9 Dense fibrous tissue in the fibroid causes acoustic shadowing.
Figure 4.10 Multiple fibroids distorting the outline of the uterus and altering the texture of the myometrium.
Figure 4.11 The dark (hypoechoic) area within the myometrium of the uterus indicates the pathology, a uterine fibroid.
Endometrial Polyp
Endometrial polys are localised overgrowths of endometrial glands and stroma, with a central vascular core, that project out from the lining of the endometrium. They are a relatively common incidental finding, with one study of 686 randomly selected Danish women aged 20–74 years reporting diagnosis of a polyp in 5.8% of premenopausal and 11.8% of postmenopausal women (Dreisler et al., 2009). The majority of polyps are benign, with one meta-analysis reporting 1.7% of polyps in premenopausal women were either hyperplastic or had focal malignant changes, with this proportion rising to 5.42% in postmenopausal women (Lee et al., 2010).
There is evidence that polyps may reduce pregnancy rates. Endometrial polyps may decrease fertility by physical mechanisms such as interference with implantation or sperm transport, or alterations in the immunological or cytokine microenvironment of the uterine cavity. A randomised controlled study of 215 infertile women with an endometrial polyp reported a statistically higher cumulative pregnancy rate of 51.4% after four intrauterine insemination cycles in women who underwent hysteroscopic polypectomy prior to fertility treatment compared to 25.4% in women who did not undergo polypectomy prior to their treatment (p < 0.01) (Perez-Medina et al., 2005).
The appearance of an endometrial polyp on ultrasound is an echogenic or isoechoic mass in the cavity of the uterus. Ultrasound diagnosis of endometrial polyps can be difficult, as the endometrial polyps can merge with the background echogenicity of the endometrium. Polyps should be imaged in both long and transverse planes to confirm.
