Investigation the effect of oxytocin hormone on pelvic floor muscles in pregnant rats

Oxytocin which is commonly used in the augmentation and induction of labor causes in greater mechanical strength in the pelvic floor muscles and nerves, resulting in more pelvic floor damage with extension of these muscles. There have been few studies on this issue and no consensus has been reached. Therefore, the present study was designed as a randomized controlled trial to determine the effect of oxytocin induction on pelvic floor muscles in pregnant rats. A total of 32 Wistar Albino rats were randomly divided into four groups. Group I is composed of 8 virgin rats. Group II is composed of 8 rats which spontaneously gave vaginal birth. Group III, control group, were induced by intravenous route with saline solution and Group IV was named as oxytocin group. The rats in this group were induced with 2.5 mU iv oxytocin (Synpitan Forte, Deva, Istanbul) on the 21st day of pregnancy in pulses for 8 hours every 10 minutes (n = 8). Then, the rats under deep anesthesia who gave birth within 24 hours; m. coccygeus, m. iliocaudalis, m. pubocaudalis muscles were dissected and tissue samples were taken. The obtained tissues were examined under light microscope. Data were analyzed with IBM SPSS 23. Comparisons between groups were analyzed with one-way variance analysis and multiple comparisons were performed with Tukey HSD. The relationship between body weight and pelvic floor muscle was examined by Pearson correlation. When all groups compared among themselves, there was no difference between the mean values of m. iliocaudalis muscle (p>0.05). In the oxytocin induction group, the mean value of m. pubocaudalis muscle size was statistically significant (50.1 ± 5.4 µm ve p<0.001) compared to the other groups. In the saline solution induction group, the mean value obtained from m. coccygeus muscle size was found to be statistically significant compared to the virgin group (49.5 ± 10.9 µm and p <0.009). According to our study, there was no difference in m. iliocaudalis muscle size between all groups. In contrast, m. pubocaudalis muscle size was significantly higher in oxytocin group. In the saline solution induction group, it was concluded that m. coccygeus muscle size was significantly higher.