Correlations of third-trimester hiatal biometry obtained using four-dimensional translabial ultrasonography with the delivery route in nulliparous pregnant women

Factors involved in changes in the levator ani during pregnancy

INTRODUCTION AND HYPOTHESIS

Levator ani muscle (LAM) dimensions increase during pregnancy to allow the delivery of the fetus. The objective was to investigate which factors are involved in LAM modifications during pregnancy.

METHODS

A prospective longitudinal observational study was conducted between July 2015 and March 2018. Ninety-nine nulliparous pregnant women were included. Data on the physical examination, 4D transperineal ultrasound and hormonal concentrations (progesterone, oestradiol and relaxin) were collected during the first and third trimesters.

RESULTS

We found higher hiatal dimensions at the beginning of pregnancy than in other studies with nonpregnant women. Increases in the levator ani hiatal (LH) dimensions were observed at contraction (1.01 ±1.96 cm2), rest (0.82 ± 2.51 cm2) and on Valsalva (2.36 ± 3.64 cm2) throughout pregnancy. The distensibility in the third trimester was higher than in the first trimester (5.79 vs 4.24 cm2; p=0); however, the contractility was lower (-3.32 vs -3.5 cm2; p=0.04). Women with lower scores on the Modified Oxford Grading Scale in the third trimester presented with lower contractility in the LAM. A larger LH at the end of pregnancy was associated with age and body mass index. Eleven women developed ballooning during pregnancy; in these women, relaxin was higher in both trimesters than in women without ballooning, but these results were not statistically significant. The linear models to predict third-trimester Valsalva LH, distensibility and contractility were not conclusive and did not show any factors to predict LAM modifications during pregnancy.

CONCLUSIONS

Hormones could play a role in modifying the muscle properties of LAM from the beginning of pregnancy, but we did not find an association between LAM measurements and hormone concentration in this study.

Perineal Ultrasound Versus Magnetic Resonance Imaging (MRI) Detection for Evaluation of Pelvic Diaphragm in Resting State

BACKGROUND The aim of this study was to compare the consistency differences between ultrasound and MRI detection methods and the reliability between 2 independent observers. MATERIAL AND METHODS Under 2 kinds of states - the resting state and muscle contractions state - intra-class correlation coefficients (ICCs) were calculated and the consistency of 2 diagnostic methods was evaluated by 2 independent observers. We also assessed the interscorer reliability of the 2 observers. RESULTS In terms of the evaluation of biological parameters of the pelvic diaphragm, the consistency of the 2 diagnostic methods was moderate. The ICC of pelvic diaphragm area was 0.55 (95% CI 0.35-0.71), anteroposterior diameter was 0.48 (95% CI 0.28-0.64), and transverse diameter was 0.43 (95% CI 0.25-0.63). The ultrasound detection values of the perineal ultrasound were significantly smaller than those of the MRI. In addition, these differences were increased with the rise of the pelvic diaphragm area. CONCLUSIONS By evaluating the pelvic diaphragm in patients with pelvic organ prolapse in the resting state, it was preliminarily confirmed that the consistency of ultrasound and MRI was only moderate. The comparison of these 2 diagnostic methods under the dynamic muscle contraction state needs to be further explored.