According to translational research, the pelvic floor (PFM) and rectus abdominis muscles (RAM) showed a myopathic process1 presence of hyperglycemia in pregnant rats and GDM women. These investigations, however, did not look at changes in the contractility and distensibility of the levator hiatus. Our hypothesis was that GDM women will exhibit PFM dynamic abnormalities indicating of lower strength compared to pregnant women without GDM using 3D-TPUS. 2 Our major aim was to investigate and compare the dynamic morphometry of PFM using 3D-TPUS, as well as the development at two third-trimester time periods in women with and without GDM.

This was prospective cohort study approved by the Institutional Ethical Committee (Protocol Number CAAE 82225617.0.0000.5 411). The main inclusion criteria were: pregnant women between 24-30 weeks of gestation in the first assessment; singleton pregnancy; 18–40 years of age; primigravida or primiparous with previous c-section. The participants were allocated in GDM group if they presented fasting glycemic levels ≥92 mg/dL or 1 hour ≥180 mg/dL or 2 hours ≥153 mg/dL. In addition, participants who had lower levels composed the Non-GDM group. Participants were evaluated at two time points: 24–30 weeks of gestation (T1), at 36–38 weeks of gestation (T2). The same procedures were followed at each time point. During first step of the investigation the participants answered a questionnaire, followed by instructions about pelvic floor contraction. After the confirmation that they were prepared to perform the main acquisition, the 3DUS data collection were performed. After confirming that the participants understood and performed all functions correctly, an experienced 3D-TPUS investigator obtained the PFM images. The participants had two predetermined times to perform the previously instructed pattern. The AGE Voluson I system was employed, along with a RAB 2-6RS (2-6 MHz) curved array 3D transducer (GE Healthcare, Zipf, Austria). The condom-covered probe was positioned on the perineum in the sagittal plane. The sagittal plane's field of view angle was set to 70°, while the coronal plane's field of view angle was set to 85°.3 In terms of the 3D-TPUS protocol acquisition, three separate images were gathered in the following order and colors: 1) One gray picture was collected at rest with no pelvic floor movement to be utilized as a reference basal measurement to determine the index from rest to functional activity; 2) One sepia image at maximum voluntary PFM contraction; 3) and one blue image at maximum distension obtained during the Valsalva maneuver.

PDRC recruited and tracked a total of 110 pregnant women over the study period. The study's eligibility criteria were met by 104 people (94%). In the end, 83 participants (80%) were included in the study, 38 in the GDM group and 45 in the non-GDM group. Table 1 shows the sociodemographic and clinical characteristics of the individuals. As expected, the non-GDM and GDM groups revealed significant differences on the OGTT-75g, fasting (p<.001), after 1 hour (p<.001) and after 2 hours (p<.001). Furthermore, there were still variations in glycemic levels between the groups at 38-40 weeks of gestation (p=.002) (Table 1). Table 2 summarizes the results of static (at rest) and dynamic (PFM contraction and distension) morphometry. Comparisons of PFM contraction, distension, and mobility dimensions between GDM and non-GDM groups at 24-30 weeks of gestation revealed no significant changes in the LH dimensions.The LHarea (P<.000) showed reduced constriction in the GDM group compared to the non-GDM group at 38-40 weeks of gestation. In the GDM group, 
LHap (P<.001), LHrl (P=.001), and LHarea (P<.001) had less distension. In terms of mobility, LHap (P<.001), LHrl (P=.001), and LHarea (P<.001) dimensions were less mobile in the GDM group.Table 3 shows the comparison of PFM at the two gestational stages in all LH dimensions in each group.  The GDM group experienced a significant decrease (P=.000) in LHarea contraction, distension, and mobility during pregnancy. The non-GDM group, on the other hand, showed higher distension in transverse diameter (LHrl) (P =.046) and LHarea (P=.000), as well as more mobility in LHap (P=.032), LHrl (P=.048), and LHarea (P=.000). from 24 to 28 weeks through 36 to 40 weeks of gestation.

The maternal PFM dynamic 3D-TPUS evaluation in GDM women at two time periods during the third trimester of pregnancy was compared between women with and without GDM in this hypothesis-generating analysis; Thus, GDM women had lower PFM contractility, distensibility, and mobility at 38-40 weeks of gestation compared to non-GDM women. Our findings of less functional PFM using 3D-TPUS assessment include GDM as an epidemiological factor for the development of PFD in pregnancy, which warrants further investigation.

Our data indicate that maternal GDM exposure may lead to a loss of PFM functioning, as measured by decreased PFM contractility, distensibility, and mobility compared to non-GDM women. Furthermore, as these muscles move to a lower functional muscle near the end of pregnancy, GDM may decompensate the PFM maternal adaption for normal delivery.

Marini G, Pascon Barbosa AM, Damasceno DC, Michelin Matheus SM, De Aquino Castro R, Castello Girão MJB, et al. Morphological changes in the fast vs slow fiber profiles of the urethras of diabetic pregnant rats. Urogynaecologia. 2011;25.
Rudge MVC, Souza FP, Abbade JF, Hallur RLS, Marcondes JPC, Piculo F, et al. Study protocol to investigate biomolecular muscle profile as predictors of long-term urinary incontinence in women with gestational diabetes mellitus. BMC Pregnancy Childbirth [Internet]. 2020;20:117. Available from: https://bmcpregnancychildbirth.biomedcentral.com/articles/10.1186/s12884-020-2749-x
Dietz HP. Ultrasound imaging of the pelvic floor. Part II: three-dimensional or volume imaging. Ultrasound Obstet Gynecol. 2004 Jun;23(6):615–25.

Continence 2S2 (2022) 100294
DOI: 10.1016/j.cont.2022.100294