User:Aigen1959/Impacts of Pregnancy on the Voice

= Impacts of Pregnancy on the Voice =

Increase of Estrogen and Progesterone
Hormonal fluctuations can cause serious impact on the functionality and structure of the vocal folds. During pregnancy, a different form of estrogen is created by the placenta to help support the pregnancy by maintaining the lining of the uterine walls, increasing blood flow throughout the body, suppressing the other hormones required for ovulation, helping develop vital organs for the fetus, and inducing the growth of breast tissue and milk ducts for breastfeeding. During a time where higher levels of estrogen are present in the body, women often report feelings of hoarseness and overall vocal fatigue. Elevated estrogen levels of pregnancy cause a thickening of the vocal fold skin which alongside increased progesterone levels might contribute to feelings of vocal weight, dryness, and fatigue. Some women also experience a drop of pitch in their normal speaking range as well as their singing. Estrogen also contributes to a reduced respiratory capacity in the late stages of pregnancy alongside the displacement of the internal organs due to the growth of the uterus. Elevated estrogen levels cause fluid retention and swelling throughout the body caused by the increased blood flow to aid placental growth. Estrogen also causes water retention. The laryngeal structure is impacted by this blood flow which can compromise the vocal folds. Straining or overusing swollen vocal folds and blood vessels in the laryngeal structure could cause lesions on the folds, and in worst case scenarios, vocal fold hemorrhages.

Progesterone is another common hormone found in the female body that occurs during a regular menstrual cycle that also spikes during the early weeks of pregnancy. Progesterone in the menstrual cycle helps create a thick lining of the uterus for the implantation of an embryo. During the initial stages of pregnancy, progesterone is responsible for upkeep and growth of the uterine lining and maintaining an environment for a viable pregnancy before production is taken over by the placenta.

During the luteal phase in the menstrual cycle, the body undergoes fluctuations of estrogen and progesterone which cause reactions in the laryngeal structure. A similar response seen during the luteal phase is replicated in pregnancy as hormones rise and fall. Higher progesterone often is reported to cause feelings of dryness and increased weightiness and thickness to the vocal folds. Progesterone also causes vocal fold secretions to thicken and add to any feelings of congestion. One of the roles of progesterone in pregnancy is to relax and stimulate modifications to the muscular system which can cause the process of respiration and phonation to change.

Related to pregnancy, estrogen causes fluid retention, swollen mucosa, blood vessels, and feelings of weightiness. Elevated levels of estrogen can cause swelling at the level of the folds causing phonation to become more uncomfortable and even painful.

Nausea, Vomiting, and Reflux
During the early stage of pregnancy, the body experiences a drastic increase of hormones that reroute the entire emotional and physiological process. Estrogen and progesterone dramatically rise immediately following conception due to the sudden introduction of the human chorionic gonadotropin hormone (hCG) which prompts the body to create higher levels of hormones to support pregnancy.

Researchers theorize that the change of hormones is the root of the iconic morning sickness. Although nausea and vomiting are often associated with early pregnancy, and is experienced in 50-90% of pregnancies, it is completely normal for it not to subside in the second and third trimesters. The acidity of stomach contents causes irritation to the tissue of the vocal folds and esophagus which can contribute to feelings of dryness and general discomfort in the larynx and pharynx. Some women experience hyperemesis gravidarum. In a recent study about the impacts of hyperemesis on the voice researchers described, "'Pregnancy is a complex process that has an impact on emotional, functional, and physical well-being. Similarly, a variety of factors influence vocal quality. According to our research pregnant women with hyperemesis complaints generally mentioned emotional and functional voice impairments. The lack of a structural abnormality or lesion affecting the vocal cords can be explained by the fact that the F-vhi-10 [self- assessment scale for vocal functionality] scores were not statistically different between the two groups [control and hyperemesis group]. If the contents of the stomach frequently upset the esophagus, supraglottic, and oropharyngeal mucosa, hyperemesis can create swallowing issues.'"Women who experience some form of vocal impairment following the effects of hyperemesis gravidarum do not receive any form of structural damage and any difficulties can be attributed to functional or psychological issues.

Progesterone is necessary for healthy, full-term pregnancy for many reasons including the ability for muscle and tissue to relax for the uterus to expand to accommodate the growing fetus. As a result, other muscles in the body are forced to relax including the ring at the base of the lower esophageal sphincter which shuts the stomach contents off from traveling back up into the esophagus. Because of this, a little over 50% of women report experiencing some form or severity of gastroesophageal reflux disease (GERD) and/or laryngopharyngeal reflux (LPR).

Reflux can cause various issues for the voice and pharynx including swelling of the laryngeal structure, redness, hoarseness, and a thicker mucosa. Without proper treatment, reflux can have permanent damage on the esophagus, larynx, and even lead to irreversible vocal injury. Pregnant women and their voices are more susceptible to this damage caused by reflux due to their higher levels of hormones, specifically progesterone, and reorganization of the intestines, and increased intra gastric pressure.

Respiratory Changes
Breathing is vital to life and one of the most important things for phonation in the larynx. Progesterone is one of the hormones responsible for encouraging the body to increase respiration towards the end of pregnancy. Towards the final stages of pregnancy, the ability to maintain airflow throughout the respiratory tract worsens due the relaxations of the bronchial tree muscles caused by hormonal changes.

An obvious contribution to respiratory changes is the accommodation of the uterine walls for the growing fetus causes the respiratory system to shift upwards into the chest cavity and change shape. Researchers depict in their findings, “The average subcostal angle of the ribs at the xiphoidal level increases from 68.5 at the beginning of pregnancy to 103.5 at term.” The respiratory system is trying to preserve lung volume throughout the upward movement of the uterus. There is an obvious change in the shape of the ribcage and location of the respiratory organs but there does not appear to be a change in the volume of the lungs due to the ability to shift and reorganize the breathing mechanisms.

Airway Changes in Labor and Delivery
Throughout pregnancy, the respiratory and airway tract are impacted and reorganized, but during the active delivery stage the airway can undergo an obvious changee. The research done on the topic of airway changes in labor and delivery are primarily targeted towards anesthesiologists to show the risks of intubating a laboring woman and the importance of frequent airway checks throughout childbirth. The study used the Mallampati Score for rating the airway and the ease of intubation on groups of women from the beginning of active labor up until delivery. Any woman who began labor with a Class airway and/or ended up undergoing a cesarean section was disqualified from the study. The study detailed that 82% of women who began early active labor (2-3cm) with Class 1 or Class 2 airway would often end labor with a Class 4 before returning to their original class 36-48 hours (about 2 days) postpartum. The class of the airway also appeared to change throughout pregnancy presumed to be caused by the significant amount of fluid retention. Their study found that women are likely to experience a decrease in pharyngeal volume during the final stages of pregnancy, labor and delivery, and in the postpartum period directly related to the pushing of vaginal birth. They theorized that this could be due to the strain of pushing causing veins to swell and muscles to contract. They concluded that the cause of the drastic airway changes in labor and delivery, agreed that a combination of general pregnancy fluid retention and the strain of contractions and pushing caused a decrease in pharyngeal volume which visibly improved quickly following birth but takes time to fully recover.

Abdominal Muscles and the Diaphragm
From the very beginning at the time of fertilization, the body begins producing more levels of progesterone to encourage growth of the uterine lining and relax any smooth muscle tissue in the body. This is primarily directed towards the abdominal and uterine muscles to expand to accommodate the developing fetus and by the end of the second trimester the abdominal muscles split directly down the middle.

The abdominal muscles are vital for phonation and the extreme distention of the abdomen can disrupt the phonation process. During pregnancy, the abdominal muscle must split, making some form of extra tension to phonate almost inevitable. The overall curvature, angle, and general placement of the diaphragm changes as pregnancy progresses. One study indicated their findings about the strength of the diaphragm by the end of pregnancy, that although the diaphragm undergoes major shifts during pregnancy, there could be some form of benefit.

Studies show that the diaphragm shifts 5 centimeters higher into the chest cavity by the end of the third trimester. In respiration, the diaphragm plays a significant role in inhalation and creating the vacuum to pull air into the lungs. Any disruptions to the respiratory process cause difficulties in phonation since it relies so heavily on proper inhalation and controlled exhalation.

Abdominal Muscles in Labor and Delivery
The uterus and the abdominal muscles undergo copious amounts of stress throughout the delivery process. While the uterus does most of the contracting, the abdominal muscles and diaphragm have gone through 9 months of consistent stretching and growth to accommodate the growing fetus. This entire process is enabled by elevated levels of progesterone which encourages muscles throughout the body to relax. By the time childbirth occurs, the abdominal muscles and diaphragm have undergone major changes, making contracting the uterus more impactful.

Throughout pregnancy, the abdominal muscles have an additional role of supporting the growing fetus and the expanding uterus. During childbirth the diaphragm and abdominal muscles might take on another role as stated, “...The diaphragm and the abdominal muscles are also important during the delivery stage, when they have to contract forcefully, acting as a brace and being the ‘engine’ that expels the fetus.” The abdominal muscles and diaphragm play a role in the delivery stage and could sustain some form of damage due to the extended exposure to intense contracting of a surrounding muscle.