Clinically significant changes in anal sphincter hiatal area in patients with gestational diabetes mellitus and pelvic organ prolapse.

Background: The prevalence of pelvic organ prolapse (POP) increases with age and parity. Specifically, the prevalence of POP among women aged 20 to 39 is 9.7%, while it rises to 49% among women over 80 years old. Additionally, as the number of deliveries increases, the prevalence of POP also rises accordingly, with a rate of 12.8% for women with one delivery history, 18.7% for those with two deliveries, and 24.6% for women with three or more deliveries. It causes immense suffering for pregnant women.

Aim: To evaluate the relationship between the levator ani muscle's hiatus (LH) area and POP in patients with gestational diabetes mellitus (GDM) using perineal ultra-sound.

Methods: The study cohort comprised 104 patients aged 29.8 ± 3.7 years who sought medical care at our institution between January 2021 and June 2023. All were singleton pregnancies consisting of 75 primiparas and 29 multiparas, with an average parity of 1.7 ± 0.5. According to the POP diagnostic criteria, the 104 subjects were divided into two groups with 52 members each: POP group (patients with GDM combined with POP) and non-POP group (patients with GDM without POP). Perineal ultrasound was used to measure differences in the anteroposterior diameter, transverse diameter, and LH area. Receiver operating characteristic curves were drawn to determine the optimal cutoff values for the LH anteroposterior diameter, transverse diameter, and area for diagnosing POP.

Results: Statistically significant increase in the LH area, anteroposterior diameter, and lateral diameter were observed in the POP group compared with the non-POP group (P < 0.05). Both groups exhibited markedly elevated incidence rates of macrosomia and stress urinary incontinence. For the POP group, the area under the curve (AUC) for the LH area was 0.906 with a 95% confidence interval (CI): 0.824-0.988. The optimal cutoff was 13.54cm², demonstrating a sensitivity of 83.2% and a specificity of 64.4%. The AUC for the anteroposterior diameter reached 0.836 with a 95%CI: 0.729-0.943. The optimal cutoff was 5.53 cm with a sensitivity of 64.2% and a specificity of 73.4%. For the lateral diameter, its AUC was 0.568 with a 95%CI: 0.407-0.729. The optimal cutoff was 4.67 cm, displaying a sensitivity of 65.9% and a specificity of 69.3%. Logistic regression analysis unveiled that age, body weight, number of childbirths, total number of pregnancies, and gestational weight gain constituted the independent risk factors for the cooccurrence of GDM and POP.

Conclusion: Three-dimensional perineal ultrasonography of LH size and shape changes can effectively diagnose POP. Age, weight, number of births, number of pregnancies, and weight gain during pregnancy are independent risk factors affecting the cooccurrence of GDM and POP. GDM can increase the LH area in patients, and an enlarged LH leads to an increased incidence of POP.