Mouth Guard Use in the Second Stage of Labor
Condition: Dystocia; Fetal; Labor Long; Cesarean Section, Affecting Fetus or Newborn
MeSH terms: Dystocia
Study type: Interventional

Summary: 
      Shortening the second stage of labor, the time spent pushing the baby out, is important for
      positive mother and infant's outcomes. Lack of progress of labor for any reason is the most
      common reason for cesarean section in women having their first baby and the second most
      common reason for cesarean section in women who have already had a baby. In 2014, a large
      study done across the United States showed increases in complications in both mother and
      infant when pushing was prolonged, including uterine infection, postpartum hemorrhage, more
      extensive vaginal tearing, shoulder dystocia, 5 minute Apgar score less than 4, infant
      admission to Neonatal Intensive Care Unit and neonatal infections. Therefore, the challenge
      is to consider alternative practices in order to maximize a mother's chance of a vaginal
      delivery and minimize these associated risks to both mother and baby.

      Mouth guards are used primarily in contact sports, and have been demonstrated to reduce or
      prevent injury to the teeth. Additionally, it has been proposed that wearing a mouth guard
      increases the strength of different muscle groups. A recent randomized controlled pilot study
      including women with their first pregnancy using a dental support device (DSD) during the
      second stage of labor evaluated the length of the second stage and outcomes. They found a
      significant decrease of 38% in the length of pushing time in the group that used a DSD.
      Additionally, there was a decreased rate of cesarean section in this group, however a p-value
      was not reported. This study only included 64 patients. A second, larger trial did not find a
      significant difference in pushing time, however the rate of interventions such as a vacuum or
      forceps-assisted vaginal delivery and cesarean section were much higher in the control group
      due to prolonged pushing. The results of the second study are contradictory in nature, yet
      the researchers do not provide hypotheses into why this may be.

      It is clear from the previously mentioned studies that further research is needed. Our
      hypothesis is that using such a device would help women to push more effectively during the
      second stage of labor thus shortening the time needed to push the baby out and increasing the
      rate of vaginal delivery. The purpose of this study is to determine whether wearing a mouth
      guard in the second stage of labor affects the length of the second stage of labor and
      improves mother & infant outcomes.
    

Detailed description: 
      Optimizing the second stage of labor is important for positive maternal and neonatal
      outcomes. Dystocia of labor refers to a lack of progress of labor for any reason, and it is
      the most common indication for cesarean delivery in nulliparous women and the second most
      common indication for cesarean delivery in multiparous women. In 2014, a large US multicenter
      cohort study showed increases in maternal and neonatal morbidities when the second stage was
      prolonged, including chorioamnionitis, postpartum hemorrhage, 3rd and 4th degree perineal
      laceration, shoulder dystocia, 5 minute Apgar score less than 4, neonatal admission to NICU
      and neonatal sepsis. Therefore, clinicians are challenged to consider alternative practices
      in order to maximize a mother's chance of a normal delivery and minimize these associated
      risks to both mother and baby.

      Mouth guards are used primarily in contact sports, and have been demonstrated to reduce or
      prevent injury to the teeth. Most commonly made of synthetic polymers, mouth guards function
      as a shock-absorber. Even among sports medicine literature, there is a call for more research
      into use and education about protective gear. Previous studies have shown that wearing a
      mouth guard increases the isometric strength of different muscle groups. Recent studies have
      begun to explore whether wearing a similar style mouth guard will shorten the duration of the
      second stage of labor. A recent randomized controlled pilot study including nulliparous women
      using a dental support device (DSD) during the second stage evaluated the length of the
      second stage and outcome thereof. They defined the second stage of labor as the time between
      complete cervical dilation and fetal expulsion. They found a significant decrease of 38% in
      the length of the second stage in the group that used a DSD. Additionally, there was a
      decreased rate of cesarean section in this group, however a p-value was not reported. This
      study only included 64 patients. A second, larger trial also looking at nulliparous women did
      not find a significant difference in length of second stage of labor however the rate of
      obstetrical interventions such as operative vaginal delivery and cesarean section were much
      higher in the control group due to prolonged second stage of labor. Though the results of the
      second study are contradictory in nature, the researchers do not provide hypotheses into why
      this may be.

      Our hypothesis is that using such a device would help women to push more effectively during
      the second stage of labor thus shortening the second stage and increasing the rate of
      spontaneous vaginal deliveries that do not require operative intervention. Developing a way
      to shorten the second stage of labor and reduce the number of cesarean sections or
      instrumental deliveries could reduce the morbidity of mothers and their infants and decrease
      health care spending.
    

Intervention name(s): Mouth Guard
Intervention type(s): Device
Intervention description(s): Patient will wear mouth guard while pushing in the second stage of labor
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: This will be a randomized controlled trial in which patients who make it to the second stage of labor will be randomized to wear a mouth guard while pushing during the second stage of labor or continue through the second stage of labor without a mouth guard. They will be randomized in a 1:1 fashion using RedCap.
Masking: None (Open Label)
Primary purpose: Prevention
Keywords: second stage; spontaneous vaginal delivery