Pregnancy and its changes is a normal physiological process that happens in all mammalian in response to the development of the fetus. These changes happen in response to many factors; hormonal changes, increase in the total blood volume, weight gain, and increase in fetus size. All these factors have a physiological impact on all systems of the pregnant woman; musculoskeletal, endocrine, reproductive system, cardiovascular, respiratory, gastrointestinal system, and renal changes. The full pregnancy period is about 40 weeks
Anatomy
Four pairs of abdominal muscles combine to form the anterior and lateral abdominal wall and may be termed the abdominal corset. Transversus abdominis lies deep to the internal abdominal oblique and external abdominal oblique with the rectus abdominis central, anterior and superficial IO, EO and TrA insert into an aponeurosis joining in the midline at the linea alba. The deep abdominal muscles, together with the pelvic floor muscles, multifidus, and diaphragm, can be considered as a complete unit and may be termed the lumbopelvic cylinder. This provides support for the abdominal contents and maintains intraabdominal pressure.
Organs of the female reproductive system present in the pelvis are subdivided into internal and external genitalia. The internal genitalia consists of the uterus, two uterine tubes, two ovaries, and the vagina. The external genitalia, mainly consist of the mons pubis, clitoris, labia majors, labia minora, and Bartholin glands.
Endocrine System Changes
Pregnancy is a normal physiological process and is associated with changes in hormone levels, one of these hormones called steroid hormones including progesterone and estrogen they are important during pregnancy to save fetus delivery and maintenance of pregnancy stable. Its levels increase gradually with pregnancy progression, unlike relaxin reaches the highest level at first trimester then decrease at the end of pregnancy. All steroids/ sex hormones produced from the placenta during pregnancy but the progesterone is the chief one.
Progesterone at the beginning is produced by corpus luteum and reaches its maximum at 10 weeks then declined gradually and the placenta starts to produce the progesterone reaching its maximum amount at 40 weeks, the placenta production of progesterone is decreased in the last month. It is important to prevent premature uterine contractions, reduces the tone of smooth muscles causing constipation due to the water retention in the colon, decrease the tone of uterine and detrusor muscles, participate in the development of mammary glands and increase the storage of fat due to its catabolic effect on metabolism.
Estrogen, like progesterone, its production starts at corpus luteum then the placenta takes the function to produce estrogen, reaching its peak at the date of birth. Estrogen has a vasodilation effect, increases blood flow to uteroplacenta in preparing for uterine contraction. In addition to its catabolic effect and its role for the development of the mammary gland, estrogen increases water retention and maybe a receptor site for relaxin.
Relaxin is produced in the corpus luteum and later in the decidua and placenta, increases in the first trimester. it has a strong vasodilator effect, an effect on hemodynamic and affects kidney function, and affects on pelvic floor muscle relaxation.
Reproductive System Changes
During pregnancy, the internal genital tract/ reproductive systems undergone anatomical and physiological changes to accommodate the changes and development of the fetus. These changes presented as below:
Uterus, With pregnancy progression, the uterus leaves the pelvic and ascends to the abdominal cavity and the abdominal content displaced in response to the increased size of the uterus which is five times more than normal this increases in the size of uterus associated with an increase of blood supply to the uterus and uterine muscle activity, uterus increases in size till the 38 weeks after that the funds level starts to descend preparing for delivery. Its weight increases from 50mg to 1000mg after that it doesn't get heavier any more and only stretches to accommodate the fetus size, and associated with an increase in the thickness and length of the fundus.
Cervix, The enlarged mucus glands of the cervix during pregnancy secretes a mucus plug
called “operculum”, act as a seal for the uterus and protect it from ascending infection, and act as a barrier between the vagina and cervix. Later in pregnancy before delivery, there is a softening of the cervix in response to the increasing uterine contractions.
Vagina, during pregnancy there is an increase in the blood supply to the vagina, its color change from pink to purple, and becomes more elastic in the second trimester.
Musculoskeletal Changes
Postural Changes
The overall equilibrium of the spine and pelvis alters as the pregnancy progresses but there is still confusion as to the exact nature of any associated postural adaptation. With weight gain, increased blood volume, and ventral growth of the fetus, the center of gravity no longer falls over the feet, increase in anteroposterior and medial-lateral sway, and women may need to lean backward to gain equilibrium resulting in disorganisation of spinal curves. Reported postures include a reduction in lumbar lordosis an increase in both lumbar lordosis and thoracic kyphosis or a flattening of the thoracolumbar spinal curve. There will be compensatory changes to posture in the thoracic and cervical spines, and this combined with the extra weight of the breasts may result in posterior displacement of the shoulders and thoracic spine, increase anterior pelvic tilting, and increase of the cervical lordosis.These changes may be still similar for 8 weeks after delivery.
Articular Changes
Altered levels of relaxin, oestrogen, and progesterone during pregnancy result in an alteration to collagen metabolism, this laxity is due to the break down of collagen in the targeted tissue and replaces it by a modified form that contains higher water content. That increases connective tissue pliability and extensibility. Therefore, ligamentous tissues are predisposed to laxity with resultant reduced passive joint stability, ligament laxity reaches its maximum at the second trimester. The symphysis pubis and sacroiliac joints are particularly affected to allow for the birth of the baby. Ligamentous laxity may continue for six months postpartum. Biomechanical changes of the spinal and pelvic joints may involve an increase in sacral promontory, an increase in lumbosacral angle, a forward rotatory movement of the innominate bones, and downward and forward rotation of the symphysis pubis. The normal pubic symphyseal gap of 4–5 mm shows an average increase of 3 mm during pregnancy
Pelvic joint loosening begins around 10 weeks, with maximum loosening near term. Joints should return to normal at 4–12 weeks postpartum. The sacrococcygeal joints also loosen. By the last trimester, the hip abductors, extensors, and the ankle plantar flexors increase their net power during gait and there is an increase in load on the hip joints of 2.8 times the normal value when standing and working in front of a worktop. As the uterus rises in the abdomen the rib cage is forced laterally and the diameter of the chest may increase by 10–15 cm.
Neuromuscular Changes
During pregnancy, the enlarged uterus results in elongation of the abdominal muscles and separation of the linea alba. Passive joint instability (as seen in pregnancy) alters afferent input from joint mechanoreceptors and probably affects motor neuron recruitment. A decrease in muscle stiffness and thus active stability of joints may result from alteration of muscle spindle regulation and this is applicable particularly to muscles around the pelvic girdle. These changes may lead to poor recruitment of the muscles responsible for pelvic girdle stability (particularly gluteus medius and maximus) and result in decreased tension of these muscles during walking, perhaps resulting in pelvic girdle pain (PGP).
Cardiovascular changes
The heart adapts to the increased cardiac demand that occurs during pregnancy in many ways. Cardiac output increases throughout early pregnancy, and peaks in the third trimester, usually to 30-50% above baseline. Estrogen mediates this rise in cardiac output by increasing the pre-load and stroke volume, mainly via a higher overall blood volume (which increases by 40–50%). The heart rate increases, but generally not above 100 beats/ minute. Total systematic vascular resistance decreases by 20% secondary to the vasodilatory effect of progesterone. Overall, the systolic and diastolic blood pressure drops 10–15 mm Hg in the first trimester and then returns to the baseline in the second half of pregnancy. All of these cardiovascular adaptations can lead to common complaints, such as palpitations, decreased exercise tolerance, and dizziness.
Gastrointestinal changes
Progesterone causes smooth muscle relaxation which slows down GI motility and decreases lower esophageal sphincter (LES) tone. The resulting increase in intragastric pressure combined with lower LES tone leads to the gastroesophageal reflux commonly experienced during pregnancy. Nausea and vomiting of pregnancy, commonly known as “morning sickness”, is one of the most common GI symptoms of pregnancy. It begins between the 4 and 8 weeks of pregnancy and usually subsides by 14 to 16 weeks. The exact cause of nausea is not fully understood but it correlates with the rise in the levels of human chorionic gonadotropin, progesterone, and the resulting relaxation of smooth muscle of the stomach. also, constipation and hemorrhoids can occur during pregnancy.
Renal changes
A pregnant woman may experience an increase in the size of the kidneys and ureter due to the increased blood volume and vasculature. Later in pregnancy, the woman might develop physiological hydronephrosis and hydroureteronephrosis, which are normal. There is an increase in glomerular filtration rate associated with an increase in creatinine clearance, protein, albumin excretion, and urinary glucose excretion. There is also an increase in sodium retention from the renal tube so edema and water retention is a common sign in pregnant women
In the third trimester when the fetus starts to engage in the pelvis, there is an increased frequency of urination, incontinence.
Nutrition
During pregnancy, both protein metabolism and carbohydrate metabolism are affected. One kilogram of extra protein is deposited, with half going to the fetus and placenta, and another half going to uterine contractile proteins, breast glandular tissue, plasma protein, and hemoglobin. An increased requirement for nutrients is given by fetal growth and fat deposition. Changes are caused by steroid hormones, lactogen, and cortisol. Pregnant women require a caloric increase.also there's a weight gain of 20 to 30 lb (9.1 to 13.6 kg).
Problems may have during pregnancy
2-Symphysis pubis dysfunction.
3-Rib pain.
4-Nerve compression syndromes.
5-Back pain.
7-Muscle cramps.
8-Morning sickness.
9-Edema.
10-Pre-eclampsia
Why You Should Do Physiotherapy in Pregnancy
Visiting a physiotherapist while prenatal, pregnant or postpartum can help both with the prevention and treatment of pain and pelvic issues caused by pregnancy as well as aid in recovery after childbirth.
Physiotherapy in Pregnancy
Here are some of the reasons why women should visit a physiotherapist in pregnancy:
Physiotherapy for Pregnant Women
Physiotherapists can work with women to help them prepare their bodies for pregnancy including ensuring the body is aligned
and ready to carry a baby. If your body is already compensating for
previous injuries, pregnancy can add further strain and pain.
Physiotherapy can also teach pregnant women how to correctly perform
Kegel exercises which will help strengthen the pelvic floor in
preparation for childbirth.
Kegel exercise consists of repeatedly contracting and relaxing the muscles of the pelvic floor.
Physiotherapy Assists with Posture Changes during Pregnancy
Pregnancy puts a huge strain on a woman’s body. The physiological changes that come with pregnancy include an increase in body mass, retention of fluid and laxity in supporting structures.
These changes cause postural adaptations such as an alteration in the loading and alignment of the spine and weight-bearing joints that often cause back pain and pelvic pain that is associated with pregnancy.
Core stability training with a physiotherapist is one way to help prevent and treat back pain during and following pregnancy.
You Learn How to Push Correctly During Labour
Using their knowledge of the pelvic floor, physiotherapists can help
teach women how to push effectively during childbirth. Pushing correctly
will reduce the chances of pelvic floor trauma and subsequent problems.
Physiotherapy Assists with Pelvic Floor Rehabilitation
Throughout pregnancy and labour, a women’s pelvic health can be
compromised. Physiotherapists have specific training to assess the
muscles, connective tissues and nerves in the pelvic floor.
Some conditions that can arise from trauma to a woman’s pelvic floor include incontinence, pain during intercourse, and pelvic organ relapse.
After a woman has had a baby, an assessment and a plan for rehabilitation will assist in the recovery of her pelvic floor.
Reference
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