Vaginal delivery and intrapartum characteristics including episiotomy and perineal tears are considered risk factors for pelvic floor disorders (PFD) including urinary incontinence, fecal incontinence, and pelvic organ prolapse [1]. Pelvic floor muscle training is recommended for pregnant and postpartum women as a treatment and prevention of PFD [2], however little is known about pelvic floor muscles (PFM) function during the early postpartum period. To our knowledge, the comparison of PFM function regarding perineal trauma and assisted vaginal delivery shortly after delivery was not studied before. We aimed (1) to assess the ability to voluntary contract PFMs shortly after vaginal delivery and (2) to compare early postpartum PFM function among women with an intact perineum, perineal tears, episiotomy, and assisted vaginal delivery (vacuum extractor).

We have conducted a retrospective analysis of medical records from PFM examination that have been performed in primiparous women 24-72 hours after vaginal delivery as a part of standard care in our hospital. Vaginal examination of PFM function included assessment of: (1) PFM strength - maximal voluntary contraction (MVC) evaluated with Modified Oxford Scale (0-5); (2) PFM endurance measured in seconds (0-10 seconds), (3) MVC repetitions (0-10 repetitions), and (4) PFM coordination evaluated with fast PFM contractions (0-10 repetitions). Furthermore, we assessed the ability to perform correct, isolated voluntary PFM contraction without breath holding (yes/no), relaxation of PFM (yes, partial/delayed, non-relaxing), and muscle tone (decreased, normal, increased). The function of PFMs was analysed in groups separately and compared between women with intact perineum and women with first-degree perineal tear. Further, we compared women with no injury or first-degree tear to those who had episiotomy, 2nd and 3rd degree perineal tears, those after assisted vaginal delivery. Given the significant discrepancies in group sizes, the analysis employed a random sampling technique adhering to a 1:2 ratio, whereby for every individual in the study groups, two counterparts were randomly selected to constitute a comparably sized control group. Values of p < 0.05 were considered significant.

Total of 4612 records were included in this study. In this group 1254 (27.19%) women had intact perineum, 969 (21.01%) had first-degree perineal tear, 2020 (43.80%) received episiotomy, 90 (1.95%) had 2nd or 3rd degree of perineal tear and 279 (6.05%) had assisted vaginal delivery using a vacuum extractor. Most of the women were able to perform voluntary contraction of PFMs (87.72%). Women with intact perineum differed from those with a first-degree perineal tear in ability to voluntary contract PFMs (94.1 % vs. 91.2%, p=0.01), PFM strength (2.04±0.99 vs 1.89±0.95, p<0.001) and fast PFM contractions (7.08±2.50 vs 6.81±2.53, p=0.02). Similarly, we observed the difference between women with intact perineum or first-degree tear and women with episiotomy in PFMs strength (1.97±0.97 vs 1.87±0.96, p<0.001) and fast PFM contractions (6.96±2.51 vs 6.79±2.52, p=0.046). Comparing the women with intact perineum and first-degree perineal tear to those after assisted vaginal delivery, we observed a significant difference in PFM strength (1.93±0.96 vs 1.57±0.84, p<0.001), PFM endurance (5.14±2.41 vs 4.45±2.23, p=0.003), MVC repetitions (4.93±1.21 vs 4.69±1.28, p=0.007) and fast PFM contractions (6.83±2.49 vs 6.26±2.36, p=0.003). Moreover, women with intact perineum or first-degree injury differed from women with 2nd and 3rd degree perineal tears in PFM endurance (5.25±2.45 vs 4.61±2.26, p=0.02), and MVC repetitions (4.94±1.11 vs 4.64±1.35, p=0.02). No other statistically significant differences were observed.

To our knowledge, this is the first study that compared PFM function patterns among women with different types of perineal injuries and assisted delivery shortly after vaginal delivery. Our results showed that rate of ability to voluntarily contract the PFMs in the early postpartum period was high. Women with intact perineum generally exhibited better voluntary control on their PFMs, as well as greater PFM strength and coordination than women with first-degree tears. Greater strength and better coordination were also seen in women with no or mild perineal injury compared to women receiving episiotomy. Similarly, this group had better endurance and MVC repetitions than women with 2nd and 3rd degree tears. Women after assisted delivery showed worse outcomes in PFM strength, PFM endurance, MVC repetitions, and coordination than women with no or mild injury.

This study demonstrated that women can effectively voluntary contract their PFMs following vaginal delivery. Moreover, women with intact perineum present with greater PFM strength and better PFM coordination when compared to those with first-degree tear. Similarly, women with intact perineum and first-degree perineal tear showed greater PFM strength and better coordination than those with episiotomy, better endurance and MVC contractions compared to those with 2nd and 3rd degree perineal tears and better PFM function outcomes than after assisted vaginal delivery. Future studies need to assess whether these differences persist over time and to what extend they could be targeted with early postpartum PFM exercises. That could be especially valid for women who receive episiotomy, have perineal tears or  are after assisted vaginal delivery as they are at higher risk for developing PFD.

Hage-Fransen MAH, Wiezer M, Otto A, Wieffer-Platvoet MS, Slotman MH, Nijhuis-van der Sanden MWG, Pool-Goudzwaard AL. Pregnancy- and obstetric-related risk factors for urinary incontinence, fecal incontinence, or pelvic organ prolapse later in life: A systematic review and meta-analysis. Acta Obstet Gynecol Scand. 2021 Mar;100(3):373-382.
Romeikiene KE, Bartkeviciene D. Pelvic-Floor Dysfunction Prevention in Prepartum and Postpartum Periods. Medicina (Kaunas). 2021 Apr 16;57(4):387.

Continence 12S (2024) 101393
DOI: 10.1016/j.cont.2024.101393