Association between sexual dysfunction and avulsion of the levator ani muscle after instrumental vaginal delivery

This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1111/AOGS.13852 This article is protected by copyright. All rights reserved DR JOSE ANTONIO GARCIA-MEJIDO (Orcid ID : 0000-0002-3079-5583) DR ISABEL MARÍA AGUILAR GÁLVEZ (Orcid ID : 0000-0003-4486-7127) DR JOSE SAINZ (Orcid ID : 0000-0002-9571-3219) Article type : Original Research Article Association between sexual dysfunction and avulsion of the levator ani muscle after instrumental vaginal delivery José Antonio GARCÍA-MEJIDO1,2, Irene IDOIA-VALERO1, Isabel María AGUILARGÁLVEZ1, Carlota BORRERO GONZÁLEZ1,2, Ana FERNÁNDEZ-PALACÍN3, José Antonio SAINZ1,2 1Department of Obstetrics and Gynecology, Valme University Hospital, Seville, Spain 2Department of Obstetrics and Gynecology, University of Seville, Seville, Spain 3Biostatistics Unit, Department of Preventive Medicine and Public Health, University of Seville, Seville, Spain Corresponding author: Ana Fernández Palacín Biostatistics Unit, Department of Preventive Medicine and Public Health, University of Seville, Av. Sánchez Pizjuán, s/n, 41009 Sevilla, Spain. E-mail: [email protected] Accepted Article This article is protected by copyright. All rights reserved Conflict of interest None Funding We acknowledge support from Project PI16/01387, which is funded by Instituto de Salud Carlos III, integrated into the national I+D+i 2013-2016 plan and cofunded by the European Union (ERDF/ESF, “Investing in your future”). Accepted Article This article is protected by copyright. All rights reserved ABSTRACT: Introduction: The effects of levator ani muscle (LAM) avulsion after instrumental delivery on the sexual function of patients are currently unknown. Therefore, the objective of our study was to use a validated questionnaire, namely, the Female Sexual Function Index (FSFI), to compare the sexual function in patients with and without LAM avulsion after instrumental vaginal delivery. Material and methods: This was a prospective observational study of 112 primiparous women after instrumental (vacuum or forceps) vaginal delivery. The obstetric and general characteristics of the population were studied. At 6 months postpartum, the contraceptive method used and the occurrence of LAM avulsion (using 4D transperineal ultrasound) were determined, and the FSFI was administered. Results: A total of 100 patients (62 without avulsion and 38 with avulsion) completed the study. Thirty-eight (38%) were diagnosed with avulsion (42.1% after Kielland forceps delivery, 57.9% after Malmström vacuum delivery; p=0.837). Women with LAM avulsion had significantly lower scores for desire (2.9±1.2 vs 3.4±1.1; p=0.049), arousal (2.8±1.7 vs 3.6±1.4; p=0.014), lubrication (2.3±1.4 vs 3.0±1.2; p=0.011), orgasm (2.6±1.6 vs 3.3±1.2; p=0.006) and satisfaction (3.1±1.8 vs 3.9±1.5; p=0.051) than did women without LAM avulsion. The overall FSFI score was lower in patients with avulsion (16.7±8.9 vs 20.7±6.9, p=0.033). These results were obtained after controlling for confounders (delivery mode, induced labor, birth weight, perineal tears, avulsion degree, contraceptive method and group assignment for the parent study) in the multivariate analysis (F=4.974, p=0.001). Conclusions: Patients with LAM avulsion present a higher degree of sexual dysfunction than patients without avulsion at 6 months after instrumental vaginal delivery. Keyword sexual dysfunction, forceps delivery, levator ani muscle, 3D transperineal ultrasound, vacuum delivery Abbreviations LAM levator ani muscle FSFI Female Sexual Function Index Accepted Article This article is protected by copyright. All rights reserved Key message Patients with levator ani muscle avulsion present a higher degree of sexual dysfunction than patients without avulsion at 6 months after instrumental vaginal delivery. Accepted Article This article is protected by copyright. All rights reserved INTRODUCTION During childbirth, the sexual health of women is often neglected by health professionals in the search for optimal obstetric outcomes1. Sexual dysfunction is a frequent problem after childbirth, with a prevalence ranging from 41% to 83% at 2-3 months2,3 and up to 64% at 6 months postpartum2. However, the association between vaginal delivery and sexual dysfunction is not clear. Some studies have reported an association between vaginal delivery and sexual dysfunction4-7, but others have not found such an association8-11. Avulsion of the LAM, defined as the discontinuity of hyperechogenic muscle fibers of the puborectalis muscle at its pubic insertion12, can occur during vaginal delivery. Instrumental vaginal delivery is the factor that most influences the onset of avulsion. In fact, different rates of LAM injury have been described according to the type of delivery; an odds ratio of 6.94 (4.93- 9.78) between forceps delivery and normal delivery was found, while an odds ratio of 4.57 (3.21- 6.51) between forceps delivery and vacuum delivery was identified13. The importance of LAM avulsion lies in its association with an increase in the levator hiatus area14. Additionally, LAM avulsion leads to a reduction in the strength of the LAM15,16. The LAM plays an important role in sexual function17,18. Previous studies have shown that pregnancy can affect the function of the LAM19, which can lead to dyspareunia20; however, strengthening the LAM can improve sexual function17. Based on these premises, it is suggested that a reduction in LAM strength due to avulsion affects the onset of sexual dysfunction after delivery. Therefore, the objective of our study was to compare sexual function using a validated questionnaire, the FSFI, in patients after instrumental delivery with and without LAM avulsion. MATERIAL AND METHODS A prospective observational study was conducted in 112 primiparous patients after instrumental delivery between January 2017 and January 2019. Accepted Article This article is protected by copyright. All rights reserved The patients were recruited after instrumental delivery during their hospital stay. Consecutive patients who met the inclusion criteria were invited to participate in the study until the necessary number of patients was completed. The inclusion criteria were primiparous status, full-term gestation, cephalic presentation, instrumental delivery with a Malmström vacuum extractor or Kielland forceps, and previous provision of written informed consent. The exclusion criteria were previous pelvic floor dysfunction (chronic pelvic pain, pelvic organ prolapse, urinary or fecal incontinence), delivery completed by cesarean section after failed instrumentation and severe maternal or fetal compromise. All instrumentations were performed by qualified obstetricians with more than 5 years of experience. The instrumentations (vacuum or forceps extractions) were performed during uterine contraction and were combined with active maternal pushing, where 2-3 tractions were applied per contraction without the combined use of the Kristeller maneuver. Episiotomy was performed in a restrictive manner, and protection of the maternal perineum was performed in all cases at the time of fetal head crowning. The general parameters studied were maternal age; gestational age; labor induction; epidural analgesia use; epidural duration; second labor stage duration; episiotomy and perineal tearing, according to the Sultan classification21; and fetal weight and head circumference. The patients were evaluated 6 months after delivery, at which time they were asked about use of the following contraceptive methods during the previous 6 months: copper-bearing intrauterine device (CU-IUD), levonorgestrel-releasing intrauterine device (LNG-IUD), combined oral contraceptive (COC), depot medroxyprogesterone acetate (DMPA), condom, withdrawal or none. In addition, female sexual function was assessed using the FSFI22. The FSFI, a 19-item questionnaire, has been developed as a brief, multidimensional self-report instrument for assessing the key dimensions of sexual function in women22. A higher FSFI score implies a higher degree of sexual dysfunction. Instructions on how to complete the FSFI were provided, and the patients were given sufficient time to complete the questionnaire in a private space at the hospital. The questionnaire was used to evaluate sexual function during the last 4 weeks. The FSFI consists of 19 multiple-choice questions grouped into 6 domains: desire, Accepted Article This article is protected by copyright. All rights reserved excitement, lubrication, orgasm, satisfaction and pain. Each domain is assigned a value, and the sum of the scores of all domains defines the final score. After being administered the FSFI questionnaire, patients underwent a four-dimensional (4D) transperineal ultrasound; they did not know whether LAM avulsion had occurred when they responded to the FSFI questionnaire. This ultrasound was performed by a single examiner experienced in 4D pelvic floor ultrasound who was blinded to the obstetric data and the FSFI questionnaire data. The ultrasound evaluation was performed with a Toshiba® 500 Aplio ultrasound system (Toshiba Medical Systems Corp., Tokyo, Japan) using a 3D PVT-675 MV abdominal probe with a sterile cover. Volume acquisition was performed transperineally from the midsagittal plane, with the patient in the lithotomy position and with an empty bladder. During the exploration, dynamic 4D volumes were acquired at rest, at maximum contraction and during the Valsalva maneuver23. The hiatus was measured in the plane of minimal dimensions at the minimal distance between the hyperechogenic posterior aspect of the symphysis pubis and the hyperechogenic anterior border of the LAM just posterior to the anorectal muscle. The integrity of the LAM was evaluated under maximum contraction in the multislice mode, as previously described24,25. Complete avulsion was diagnosed when the LAM insertion was abnormal in the 3 central sections. In unclear cases, a levator-urethra gap >2.5 cm was used to define an abnormal insertion. Associations between the questionnaire (FSFI) factor scores and the presence or absence of LAM avulsion were investigated using standard linear modeling methods. Univariate analyses were performed with significant associations subjected to a multivariate analysis, which adjusted for potential confounders, including delivery mode, induced labor, birth weight, perineal tears, avulsion degree, contraceptive method and group assignment for the parent study (with and without LAM avulsion). Nonparametric univariate analysis methods, including Kruskal–Wallis tests and Spearman’s correlation, were applied in cases where the normality of the data was questionable (based on the Kolmogorov–Smirnov test and inspection of histograms). The statistical analysis was performed using the IBM SPSS Statistics program version 24 (IBM, Armonk, NY, USA). P values <0.05 were considered statistically significant. To detect a difference between the FSFI scores of 5 maternity units between the patients with and Accepted Article This article is protected by copyright. All rights reserved without LAM avulsion, considering an α=0.05 and a power 1-β=0.80, 38 patients per study group were required. With a rate of LAM avulsion of 40% in primiparous women13 and an expected rate of lost cases of 10%, we initially needed to recruit 112 primiparous women with instrumented delivery. Ethical approval The study (0153‐N‐17) was approved by the local ethics and research committees on January 31, 2017. RESULTS In total, 6325 pregnancies were reviewed, of which 2.3% (150 cases) were twins. Cesarean sections accounted for 21.3% (1348) of the cases, while 14.2% (or 899 cases) were assisted births. Preterm births before 37 weeks accounted for 7.1%, and births before 32 weeks accounted for 1.2%. Overall, 112 patients were recruited, and of these, 12 were lost to follow-up because they did not attend the consultation 6 months after delivery. A total of 100 patients completed the study, of whom 56 (56%) had deliveries with vacuum extraction and 44 (44%) had deliveries with forceps extraction (figure 1). Thirty-eight (38%) patients were diagnosed with avulsion (42.1% after Kielland forceps delivery, 57.9% after Malmström vacuum delivery (p=0.837)). The general characteristics are listed in Table 1, which also shows the differences in maternal age between the patients without and with LAM avulsion (29.7±5.2 vs. 32.0±5.6; p=0.039). All patients received epidural anesthesia. Table 2 shows the contraceptive method used most frequently during the 6 months after delivery. All women were sexually active. The contraceptive method most commonly used by the population was the copper intrauterine device (24/100; 24.0%); this was true for both patients without avulsion (14/62; 22.6%) and patients with avulsion (10/28; 26.5%). No differences were found between the groups according to the presence of avulsion. The scores on the 6 FSFI domains for the overall population and for those with and without Accepted Article This article is protected by copyright. All rights reserved avulsion are shown in Table 3. Significantly lower scores for desire (2.9±1.2 vs 3.4±1.1; p=0.049), arousal (2.8±1.7 vs 3.6±1.4; p=0.014), lubrication (2.3±1.4 vs 3.0±1.2; p=0.011), orgasm (2.6±1.6 vs 3.3±1.2; p=0.006) and satisfaction (3.1±1.8 vs 3.9±1.5; p=0.051) were found in women with avulsion than in women without avulsion. The overall score was lower in patients with avulsion (16.7±8.9 vs 20.7±6.9, p=0.034). The multivariate analysis controlled for confounders (delivery mode, induced labor, birth weight, perineal tears, avulsion degree, contraceptive method and group assignment for the parent study) (F=4.974, p=0.001). DISCUSSION Patients without avulsion scored higher on the FSFI than patients with avulsion (20.7±6.9 vs. 16.7±8.9, p=0.034). The domain with the greatest difference in score between the 2 groups was orgasm (3.3±1.2 vs. 2.6±1.6; p=0.006), as patients with avulsion had a lower score than patients without avulsion. In our study, all patients were sexually active, and after controlling for confounders (delivery mode, induced labor, birth weight, perineal tears, avulsion degree, contraceptive method and group assignment for the parent study), a multivariate analysis was performed (F=4.974, p=0.001). This finding has previously been questioned by certain authors, who reported that the effect of levator avulsion on more traditional dimensions of sexual function (i.e., desire, arousal, orgasm, satisfaction) seems to be largely negligible26. These differences may be explained by the different cohorts recruited in each study, since in our study, only patients who had instrumental delivery were recruited, of whom 38% presented avulsion compared with 14% in a previous study26. We believe that the underlying mechanism that may explain our results may be a weakening of the pelvic floor produced by the LAM avulsion16, which may even influence vaginal laxity, since it is associated with levator ani hyperdistensibility27. Nonetheless, other authors have indicated that what is most affected in the postpartum period, although temporary, is sexual desire28. However, some factors, such as the type of delivery, do not influence sexual function28-30. Actually, it is recommended that the decision to perform a cesarean section not be based on fear of the risk of postpartum sexual dysfunction31. Additionally, studies have indicated that the presence of postpartum dysfunction does not differ according to whether the assessment was performed at 6 months32 or one year31,33 after delivery. For this reason, we chose to conduct our evaluation at 6 months postpartum. Accepted Article This article is protected by copyright. All rights reserved 41 Skinner E, Barnett B, Dietz H. Psychological consequences of pelvic floor trauma following vaginal birth: a qualitative study from two Australian tertiary maternity units. Archives of Women's Mental Health, 2018; 21:341-351. Legends Table 1. Obstetric and general characteristics of the population without avulsion and avulsion. Table 2. Contraceptive method used by the study population. Table 3. Determine the Female Sexual Function Index (FSFI) score according to the existence or not of levator ani muscle (LAM) avulsion. Figure 1: Patient recruitment. Accepted Article Table 1. Obstetric and general characteristics of the population without avulsion and avulsion. Mean (±) or % All (n=100 ) Without avulsion (n=62 ) With avulsion (n=38 ) P 95% confidence interval Maternal age 30.6±5.4 29.7±5.2 32.0±5.6 0.039 -4.5 to -0.12 Gestational age 39.8±1.2 39.9±1.1 39.5±1.3 0.135 0 to 1 Induced labor 26/100 ( 26%) 18/62 (29.0%) 8/38 (21.1%) 0.483 -9.3% to 25.1% Epidural anesthesia duration (min) 420.5±188.2 427.4±203.6 410.5±168.0 0.863 -100.0 to 115.0 Second stage of labor duration (min) 91.8±57.1 94.0±61.6 88.3±49.5 0.966 -20.0 to 20.0 Episiotomy 66/67 (98.5%) 42/43(97.7 %) 24/24(100 %) 1 -6,7% to 2.18% Perineal tears 44/67( 65.7%) 29/43(67.4 %) 15/24(62.5 %) 0.790 -19.0% to 28.8% Grade I 9/61(14.8 %) 6/39(15.4 %) 3/22( 13.6%) 0.695 -16.5% to 20.0% Grade II 44/61(72.1 %) 29/39(74.4 %) 15/22(68.2 %) -17.6% to 29.9% Grade III 8/61(13.1 %) 4/39(10.3 %) 4/22(18.2 %) -26.6% to 10,8% Grade IV 0/61(0 %) 0/39(0 %) 0/22(0 %) --- Kielland's forceps 44/100( 44 %) 28/62(45.2 %) 16/38( 42.1 %) 0.837 -16.9% to 23.1% Malmström vacuum extractor 56/100(56 %) 34/62( 54.8 %) 22/38(57.9 %) -23.1% to 16.9% Fetal head circumference (cm) 34.5±1.3 34.6±1.1 34.5±1.5 0.430 0 to 1 Fetal weight at birth (g) 3334.3±325.0 3339.5±303.7 3325.9±361.4 0.841 -120.0 to 147.1 Lactation 53/100(53.0 %) 32/62(51.6 %) 21/38(55.3 %) 0.837 -23.8% to 16.4% Table 2. Contraceptive method used by the study population. Mean (±) or % All (n=100 ) Without avulsion (n=62 ) With avulsion (n= 38) p 95% confidence interval CU-IUD 24/100(24.0 %) 14/62(22.6 %) 10/38(26.3 %) 0.930 -21.1% to 13.7% LNG-IUD 7/100(7.0 %) 4/62(6.5 %) 3/38(7.9 %) -11.9% to 9.1% COC 13/100(13.0%) 10/62(16.1 %) 3/38(7.9 %) -4.3% to 20.7% DMPA 4/100(4.0 %) 2/62(3.2 %) 2/38(5.3 %) -10.5% to 6.2% Condom 17/100(17.0 %) 10/62(16.1 %) 7/38(18.4 %) -17.6% to 13.0% Withdrawal 15/100(15 %) 10/62(16.1 %) 5/38(13.2 %) -11.2% to 17.0% None 20/100(20 %) 12/62(19.4 %) 8/38(21.1 %) -17.9% to 14.6% CU-IUD, copper intrauterine device; LNG-IUD, levonorgestrel intrauterine device; COC, combined oral contraceptive; DMPA, depot medroxyprogesterone acetate. Table 3. Determine the Female Sexual Function Index (FSFI) score according to the existence or not of levator ani muscle (LAM) avulsion. aThe effect of the presence of LAM avulsion on mean domain scores for the sexual activity domain remained significant after controlling for confounders (delivery mode, induced labor, birth weight, perineal tears, avulsion degree, contraceptive method, and group assignment for the parent study) on multivariate analysis (F=4.974, p=0.001) Items Mean (±) FSFI All (n=100 ) Without avulsion (n=62 ) With avulsion (n=38 ) P 95% confidence interval Desire 3.2±1.2 3.4±1.1 2.9±1.2 0.049 3/38(7.9 %) Arousal 3.3±1.5 3.6±1.4 2.8±1.7 0.014 3/38(7.9 %) Lubrication 2.8±1.3 3.0±1.2 2.3±1.4 0.011 0.001 to 0.7 Orgasm 3.1±1.4 3.3±1.2 2.6±1.6 0.006 0.001 to 1 Satisfaction 3.6±1.7 3.9±1.5 3.1±1.8 0.051 0 to 1 Pain 3.3±1.8 3.4±1.6 2.9±2.0 0.541 -0.33 to 1 Total 19.2±7.9 20.7±6.9 16.7±8.9 0.034a 0.17 to 4.3 aogs_13852_f1.tiff Thisarticleisprotectedbycopyright.Allrightsreserved Accepted Article