Effects of isolated versus combined perineal preparation methods on perineal compliance and muscle strength: randomized controlled trial

Introduction: Perineal trauma is a very common condition and is responsible for morbidities, both in the short and long term, in women. Some strategies were developed with the aim of preventing this injury. These include perineal massage and instrument-assisted perineal stretching. However, the literature states only the effects of perineal massage in relation to postpartum variables and is still very controversial about the effectiveness of instrument-assisted perineal stretching and its application time. Objective: Comparing the effects of the instrument-assisted perineal stretching technique with different application times, in combination to perineal massage, and of the isolated techniques in relation to muscle variables and delivery endpoints. Material and methods: This was a controlled, randomized, investigator-blind, clinical trial, with concealed allocation. Ninety-six pregnant women between 18 and 40 years of age, with a gestational age of 33 weeks, pregnant for the first time or with previous pregnancies that ended before the 21st week and with a degree of strength >1 on the modified Oxford Scale, were randomized. The participants were submitted to three evaluations: before the intervention, after four sessions, and after eight sessions. The primary endpoint, distensibility of the perineal region (through Epi-No Delphine Plus®), and secondary endpoint, pelvic floor muscle contraction capacity (through Peritron®), were analyzed. In addition, after childbirth, secondary endpoints related to childbirth (route of delivery and laceration) were evaluated through a questionnaire. After the initial evaluation, the volunteers were randomly assigned to four sample groups: PnM group (n= 24), that underwent perineal massage (for 10 minutes); IStr group (n= 24), that underwent instrument-assisted perineal stretching (for 15 minutes); PnM + IStr 15’ group (n= 24), that used the two previous procedures; and PnM + IStr 2’ group (n= 24), that used perineal massage (for 10 minutes) and instrument-assisted perineal stretching (for 2 minutes). Eight interventions were carried out. Results: For perineal distensibility, an interaction occurred between group and time [F(6.142) = 2.439; p=0.028]. In the second evaluation, a significant increase of this variable was observed in the PnM + IStr 2’ group when compared to the groups that used isolated techniques. In the third evaluation, the IStr 15’, PnM + IStr 15’ and PnM + IStr 2’ groups showed higher values than the PnM group. No interaction between group and time was observed in the muscle strength evaluation, but an effect of the time [F(2.152) = 10.507; p1 na Escala de Oxford modificada. As participantes foram submetidas a três avaliações: antes da intervenção, após quatro sessões e após oito sessões. Foram analisados o desfecho primário, distensibilidade da região perineal (através do Epi-No Delphine Plus®), e desfecho secundário, capacidade de contração da musculatura do assoalho pélvico (por meio do Peritron®). Além disso, após a parição, foram avaliados desfechos secundários relacionados ao parto (via de parto e laceração), através de um questionário. Após a avaliação inicial, as voluntárias foram designadas, aleatoriamente, em quatro grupos amostrais: grupo PnM (n= 24) que realizou a massagem perineal (por 10 minutos); grupo IStr (n= 24) que foi submetido ao alongamento perineal assistido por instrumento (por 15 minutos); grupo PnM + IStr 15’ (n= 24) que utilizou os dois procedimentos anteriores e grupo PnM + IStr 2’ (n= 24) que fez uso da massagem perineal (por 10 minutos) e do alongamento perineal assistido por instrumento (por 2 minutos). Foram executadas oito intervenções. Resultados: Para a distensibilidade perineal, houve interação entre grupo e tempo [F(6,142) = 2,439; p=0,028]. Na segunda avaliação, foi observado aumento significativo dessa variável no grupo PnM + IStr 2’ quando comparado aos grupos de técnicas isoladas. Já na terceira avaliação, os grupos IStr 15’, PnM + IStr 15’ e PnM + IStr 2’ demonstraram valores superiores ao PnM. Não foi observada interação entre grupo e tempo, na avaliação de força muscular, mas foi identificado efeito do tempo [F(2,152) = 10,507; p<0,001] e do grupo [F(3,152) = 13,528; p