Physiologic changes of pregnancy

Physiologic changes of pregnancy
Prof. Aziza Tosson

AIMS TO GAIN AN UNDERSTANDING OF THE PHYSIOLOGICAL CHANGES THAT OCCUR DURING PREGNANCY

LEARNING OUTCOMES IDENTIFY THE CHANGES THAT TAKE PLACE WITHIN THE UTERUS AND BODY SYSTEMS DURING PREGNANCY CONSIDER THE EFFECT THESE CHANGES HAVE ON THE WOMAN EXPLORE THE ROLE OF THE MIDWIFE WHEN GIVING ADVISE TO THESE WOMEN

Objectives Symptoms and physical findings of each organ system
Physiologic versus pathologic changes Diagnostic tests and interpretations during physiological changes

UNDERSTANDING NEEDED TO EXPLAIN THE PHYSIOLOGICAL CHANGES THAT TAKE PLACE TO THE WOMAN TO UNDERSTAND THE MINOR DISORDERS OF PREGNANCY RECOGNISE PATHOLOGICAL CHANGES IN ORDER TO REFER APPROPRIATELY

Physiological Changes
Circulatory Thermoregulation Metabolic Respiratory Digestive Urinary Skin Breasts Biomechanical Pregnancy not only causes changes to the anatomy of the body, but also causes changes to the body systems. Many systems of the body that are affected by pregnancy.

DEFINITION THE CHANGES THAT TAKE PLACE IN THE MATERNAL ORGAN SYSTEM IN
RESPONSE TO PREGNANCY. TO ACCOMADATE THE PREGNANCY AND TO PREPARE THE WOMAN FOR LABOUR

Organ systems Cardiovascular system Pulmonary system Genital tract
Urinary system Endocrine system Gastrointestinal Tract Skin

CHANGES ARE DUE TO ALTERATIONS IN HORMONAL PRODUCTION CIRCULATION
METABOLISM

HORMONES OESTROGEN Produced in corpus luteum
Produced by placenta after 12 weeks Responsible for growth particularly of uterus and breasts

progesterone Produced in corpus luteum and then the placenta
Relaxes smooth muscle Inhibits uterine contractions until uterus is prepared for labour Regulates storage of body fat

Human chorionic gonadotrophic
Secreted from trophoblast of the developing embryo Maintains corpus luteum until placenta takes over Used in tests to confirm pregnancy

Human placental lactogen
Alters maternal metabolism Diverts glucose to fetus Mobilises free fatty acids from maternal stores

RELAXIN Released by corpus luteum then the Placenta
Softens pelvic ligaments Reduces myometrial tone

Maternal changes - anatomical and physiological
Cardiovascular changes increase in SV increase in cardiac output increase in HR at given work load increase in blood volume (mostly during latter half of pregnancy) Uterus may compress large blood vessels reducing venous return Total Body water

Circulatory System The cardiovascular system includes the heart, blood, arteries, and veins. It delivers oxygen and nutrients to all parts of the body, and to the growing baby. As a result, the pregnant soldier's heart becomes more efficient at pumping the blood to her body and to the baby. When exercising, the soldier should not exercise to the point of exhaustion or breathlessness. This is a sign that your body cannot get the oxygen supply it needs, which effects the oxygen supply to the baby as well. The soldier should not engage in activities that involve low oxygen states, such as scuba diving or mountain climbing. Is exercise safe for the baby? One of the major concerns about exercise during pregnancy is the question of diversion of maternal blood flow away from the uterus to the skeletal muscles during moderate and vigorous activity. It is believed that in moderate recreational exercise, the diversion is approximately 50 percent and in competitive athletic events can be percent. There is no research documentation of harm to the fetus, from the diversion of uterine blood flow, in soldiers who participate in regular moderate-to-high intensity exercise. The probable reason for this lack of detrimental fetal outcomes is the feto-protective, more-than-additive combination of increased blood plasma due to both aerobic training effect and pregnancy. This over-expansion reduces the fall in visceral gut blood flow and helps maintain fetal circulation during exercise. The increased red blood cells associated with exercise, as well as compensatory mechanisms of the placenta in well-conditioned, highly-fit soldiers, also helps account for the ability of the cardiovascular system to deliver needed nutrients.

Cardiovascular Changes
INCREASE DECREASE Blood volume Cardiac (heart) output Stroke volume End diastolic volume Resting pulse % of blood plasma Hematocrit Blood pressure Blood supply to uterus Cardiac reserve Vascular resistance Some of the major changes that occur to the cardiovascular system include: Blood volume increases by approximately 40 percent. The increased blood volume of pregnancy produces changes in other cardiovascular measures; however, maximal heart rates during exercise show no significant alterations due to pregnancy. Cardiac (heart) output increases. Stroke volume (volume of blood a ventricle pumps in one beat) and end diastolic volume (amount of blood in the ventricle immediately before a contraction) increases, so the heart pumps more blood per heartbeat. Resting pulse increases by as much as 8 beats per minute (bpm) in the first trimester and 15 bpm by the third trimester, in order to pump the extra blood. Percentage of blood plasma increases and percentage of red blood cells, which transport oxygen, decreases. Hematocrit (the ratio of RBC to white blood cells) decreases but can increase when vigorous exercise is performed. Blood pressure decreases somewhat; this is normal. It should remain within normal limits for the mother’s age. However, in pregnancy-induced hypertension (PIH) (high blood pressure), blood pressure increases and exercise must stop; relaxation activities should continue. Blood supply to the uterus during continuous, vigorous exercise decreases 50 percent during moderate recreational activity, and 70 percent in competitive athletic events; this decrease in blood supply appears to be okay as long as there are no other medical problems. Cardiac reserve (blood left in the heart on each stroke) decreases. Hormones of pregnancy cause the vasculature of the body to become more relaxed. Vascular resistance decreases so blood is slower to return to the heart.

Cardiovascular System
Heart shifts up and to the left Hemoglobin stays the same (12-16 g/dL) initially May drop down to 10 g/dL and still be normal physiologic anemia. Normal pregnancy Hgb is g/dL later in pregnancy Decreased Hct (38-47%) Normal pregnancy Hct is later in pregnancy Pulse rate may increase beats. Weight of uterus can cause supine hypotensive syndrome. Cardiac output-increases 40-50% Cardiac output- 6-7 liters/min vs. 3-5 l/m Blood Volume increases 1600 ml RBCs increase 20% Plasma volume increases 45-50% Stroke volume increases 50% Heart pushed left and ICS Heart Rate increases bpm Body water increases 6-8 liters Heart sounds-systolic ejection murmur Systemic vascular resistance/decreases 20% Pulmonary vascular resistance/ down 34% Arterial blood pressure/decreased 2nd trimester/ back to normal by term Wajed Hatamleh RN, MSN, PhD. 24

Supine hypotension related to Venal cava syndrome
This leads to dizziness, air hunger, nausea

Total body water Increases 6-8 L Increases by 40 % Normal body water
2/3 intracellular 1/3 extracellular ¾ interstitial ¼ intravasular 2/3 increase is extravascular

Physiologic anemia of pregnancy
Physiologic intravascular change Plasma volume increases % Beginning by the 6th wk RBC mass increases % Beginning by the 12th wk Disproportionate increase in plasma volume over RBC volume----Hemodilution Despite erythrocyte production there is a physiologic fall in the hemoglobin and hematocrit readings

Iron deficiency anemia
With erythropoiesis of pregnancy, iron requirements increase. Because large amounts of iron may not be available from body stores and may not be in the diet Supplementation is recommended to prevent iron deficiency anemia At term, Hemoglobin less than 10.0 is usually due to iron deficiency anemia rather than the hemodilution of pregnancy

Normal Iron Requirements
Total body iron content average in normal adult females is 2gm Iron requirement for normal pregnancy is 1 gm 200 mg is excreted 300 mg is transferred to fetus 500 mg is need for mom Total volume of RBC inc is 450 ml 1 ml of RBCs contains 1.1 mg of iron 450 ml X 1.1 mg/ml = 500 mg Daily average is 6-7 mg/day Small intervals between pregnancies are most concerning

Respiratory system Mechanical Consumption Stimulation diaphragm
Increase in needed oxygen Stimulation Progesterone stimulation

Physiologic changes - increase respiratory rate
RESPIRATORY SYSTEM increase respiratory rate increased oxygen consumption common are nasal stuffiness, nosebleeds due to Increased vascular swelling to nose Changes that occur in the resp system are necessary to meet the inc o2 needs of the dev fetus. See slide. Hayfever symptoms Increased vascular swelling to nose/ may cause nose bleeds, difficulty breathing etc, Cool mist humidifiers Commercially prepared saline spray Capillaires inside the nose get engorged with blood during pregnancy causing nasal congestion and epistaxisis. Diaphram elevates 4 cm. Transverse diameter increases 2 cm. Anterioposterior diameter increases 2cm. Oxygen consumption increases 15-25% Tidal volume increases 50% Respiratory rate increases slightly Increased vascularity entire upper tract 32

Respiratory Consumption O2 consumption Increases 15-20 %
50 % of this increase is required by the uterus Despite increase in oxygen requirements, with the increase in Cardiac Output and increase in alveolar ventilation oxygen consumption exceeds the requirements. Therefore, arteriovenous oxygen difference falls and arterial PCO2 falls.

Physiologic changes - Digestive system slow due to progesterone
GASTROINTESTINAL Digestive system slow due to progesterone Nausea and vomiting Ptyalism: increase salivation Heartburn Hemorrhoids Prolonged gallbladder emptying time may lead to gall stones Bile salt buildup may lead to itching. Digestive system slow due to progesterone May be due to increased HCG and estrogen Many theories about cause of nausea Gi changes are a result of the hormonal changes and inc fundal size puts pressure on internal organs Ptyalism – inc salivation 34

Gastrointestinal Tract
Displacement of the stomach and intestines Appendix can be displaced to reach the right flank Gastric emptying and intestinal transit times are delayed secondary to hormonal and mechanical factors Pyrosis is common due to the reflux of secretions Vascular swelling of the gums Hemorrhoids due to elevated pressure in veins

Physiologic changes - BMR increases by 20-25 % during pregnancy
METABOLISM BMR increases by % during pregnancy Recommended weight gain – lb Overweight – lb Underweight – lb Need for increased iron, calcium, fat, and protein 1ST TRI 3-4 LBS/MONTH 2ND 1 LB /WK 3RD 8-10 TOTAL TRI 37

Metabolic Changes INCREASES IN: Insulin level
Carbohydrate utilization during exercise as weight increases Estrogen Progesterone Relaxin Caloric requirements by ~ 300 calories/day Protein and fluid requirements A number of metabolic processes are affected by pregnancy. The metabolic system includes energy production. The amount of energy burned is measured in calories. High metabolism burns more calories. When a soldier exercises, her metabolic rate increases and she uses more calories. A pregnant soldier's metabolic rate increases to provide more energy for herself and her baby. Metabolism also involves hormone production, which increases in pregnancy. The energy balance between nutrient intake and physical exertion is complicated not only by the presence of the baby but also by fluctuations in blood sugar levels. Major changes in the metabolic system include Insulin level increases as the body seeks to store energy more often. As the placenta produces special hormones to preserve the pregnancy, these hormones block the effect of insulin. This “contra insulin” effect causes the pancreas to increase insulin production. Because insulin is released more often in a normal pregnancy, the amount of time glucose (sugar that provides energy) remains in the blood decreases. Therefore, the soldier should eat approximately 6 small meals a day to provide the body’s energy requirements and keep blood sugar levels steady. Carbohydrate utilization during exercise increases as weight increases. Estrogen increases, which promotes fetal growth and uses energy. Progesterone increases, which helps the uterus nurture the placenta. Relaxin, a protein hormone, increases. It works with estrogen to soften connective tissue and effects movement by causing joint laxity or looseness. Overall caloric requirements increase by approximately 300 calories/day. Protein and fluid requirements increase in order to make additional blood to nourish the placenta, fetus, and mother. Hyperinsulinemia The mother’s body is in a state of chronic metabolic stress resulting from an increase in fuel delivery to the blood combined with hormonal actions that rapidly deplete available fuel, creating a situation of large fluctuations in blood glucose levels. There is a tendency toward hyperinsulinemia (increased insulin production and frequency) during pregnancy. Two important implications for pregnant soldiers during exercise include: There is less glucose available to exercising muscles during pregnancy. Fatigue may be more common, and the pregnant soldier should slow down, stop exercising, and eat. Exercise & Diabetes In the general population, exercise is associated with improved functions of carbohydrate and lipid metabolism. This protection extends to pregnancy as well, and both the Second and Third International Workshop-Conference on Gestational Diabetes Mellitus endorsed the concept of pregnant diabetic soldiers pursuing an active lifestyle under medical supervision. The management of gestational diabetes through nutrition and exercise is well accepted. In some pregnant soldiers, the pancreas cannot make enough insulin to metabolize food properly. This condition is called gestational diabetes and usually goes away once the pregnancy is completed. Soldiers with gestational diabetes need to eat often and eat enough protein to maintain steady blood sugar levels. Routine and consistent exercise is beneficial to reduce high blood glucose levels. Soldiers with gestational diabetes must be carefully monitored and require close medical supervision. Due to the high levels of carbohydrate use during certain exercises such as walking and aerobic dance, non-weight bearing exercises (i.e., swimming, stationary cycle) are preferred to weight-bearing exercises.

Genital Tract Increased vascularity and hyperemia Increased secretions
Vagina Perineum Vulva Increased secretions Characteristic violet color of the vagina Chadwick’s sign Increased length to the vaginal wall Hypertrophy of the papillae of the vaginal mucosa

Physiologic changes in pregnancy - Reproductive system
Uterus – Enlarges : esp fundal area thickens, then thins later in preg Umbilicus by 20 weeks Xyphoid by 36 weeks fundus, Braxton-Hicks irregular contractions after 4 months Cervix – mucous plug, Goodell’s sign, Chadwick’s sign Ovaries –after 11 weeks, the plac prod progesterone and estrogen We have discussed the many physiologic changes that take place after the fertilization of the ovum, Now lets discuss the many physiologic changes that take place during pregnancy in mom. Let’s start with the reproductive organs – the sites of fetal development and preparation for lactation. See slide and notes. Increase in size of myometrial tissue, esp fundal area thickens, then thins later in preg Braxton hicks occur after the 4 month – irreg contractions of uterus Goodell – softening of cervix Chadwick – blue purple discoloration of cervix – both due to inc vascularization hCG from fertilized ovum maintain corpus luteum which prod progesterone to maintain preg till 4 mo =after 11 weeks, the plac prod progesterone and estrogen Breasts begin to produce colostrum in preparation for lactation 40

Changes in the cervix Length remains the same Increase in width
Softening after third month due to oestrogen Increased vascularity Increased cervical mucosa Increased glandular function

changes in size uterus grows to 30x23x20 at term weight increases to 900gms hypertrophy.. Oestrogen causes cells to increase until 20 weeks gestation Hyperplasia:- number of cells increase under the influence of oestrogen .

After 20 weeks gestation Uterine muscle tissue stretches to allow fetus to grow Progesterone relaxes the smooth muscles enabling it to stretch

Relative Uterus Size During Pregnancy
Figure 28.15

Changes in the shape of the uterus
Isthmus elongates during the 1st 10 weeks like a stalk From 7mm to 2.5cms at 10 weeks Later becomes the lower segment with the globular uterus sitting on top

ORGANISATION OF MUSCLE FIBRES
Inner circular layer Surrounds cornua, lower uterine segment and cervix Middle layer Oblique, crisscross arrangement involved in contractions to expel fetus Outer longitudinal layer Contracts and retracts thickening the upper segment

BY 12 WEEKS Uterus is upright and leans slightly to the right
No longer a pelvic organ Uterus may be palpable above the pubic bone Fetus now occupies most of the uterine cavity Placenta now developed

2ND TRIMESTA Development of the upper and lower uterine segment
Upper segment, thicker containing oblique muscles Lower segment formed from the isthmus contains circular and longitudinal muscles Uterus is pear shaped again Braxton Hicks contractions

3rd TRIMESTA Lower segment formed from isthmus and contains longitudinal fibres Upper segment thick and contains oblique muscle fibres By 36 weeks lower segment measures 8-10cms Engagement By 38 weeks the cervix is taken up into the lower segment

BLOOD CHANGES Increase in oestrogen: new blood vessels formed
growth of existing ones Therefore an increase in blood volume.

BLOOD SUPPLY TO UTERUS Blood supply pre pregnancy = 10mls/min
At 40weeks 800 – 900mls/min 20% of cardiac output goes to uterus

Blood volume: from 5 litres to 7.5
total volume up by 40-50% Red cell mass: rises constantly throughout pregancy Up by 20% by end of pregnancy

PLASMA VOLUME Increases from 10th week of pregnancy variable related to parity, fetal weight and number Reaches maximum level approx 50% above non-pregnant levels at weeks then maintained

50% rise in plasma volume 20% rise in red cell mass Heamodilution: Physiological anaemia Most apparent at weeks

RENAL SYSTEM DILATION OF THE RENAL VESSELS
DUE THE EFFECTS OF PROGESTERONE INCREASED RENAL BLOOD FLOW GFR INCREASES BY 60% IN EARLY PREGNANCY SIZE OF PORES INCREASED

Urinary Changes Kidneys grow and filter more blood as the blood volume increases Become more susceptible to bladder and kidney infections Bladder becomes compressed causing frequent urination and incontinence Help for frequent urination: Keep drinking large amounts of water Plan for bathroom breaks before the urge arises Avoid drinking a lot of fluids before bed Expect to have frequent urination day and night Do Kegel exercises regularly If burning, pain or blood occurs upon urination, tell your health care provider

Wajed Hatamleh RN, MSN, PhD.
Physiologic changes - URINARY TRACT Increased glomerular filtration rate Frequency Infection : Smooth muscle of bladder relaxes/stasis Urinary tract changes result form the inc blood volume and glom filtration rate and inc fundal size puts pressure on internal organs More susceptible to infection dt dec blood flow and traumaGFR raises by 50% Increased renal clearance leads to lowered BUN and nonprotein nitrogen values. Renal plasma blood flow increases 50% Glomerular Filtration Rate increases Bicarbonate increased excretion Creatinine increased excretion Renal pelves and ureters dilate Smooth muscle of bladder relaxes/stasis Sugar may spill at 160/protein PIH Wajed Hatamleh RN, MSN, PhD. 57

Endocrine Normal pregnancy physiology shows Postprandial hyperglycemia
“lower lows and higher highs” Postprandial hyperglycemia To ensure sustained glucose levels for fetus Accelerated starvation Early switch from glucose to lipids for fuels Insulin resistance promotes hyperglycemia Resistance-Reduced peripheral uptake of glucose for a given dose of insulin Mild fasting hypoglycemia occurs with elevated FFA, triglycerides,and cholesterol

The thermoreglation system regulates body temperature
The thermoreglation system regulates body temperature. After the first trimester, the pregnant soldier's body temperature tends to be slightly higher than the non-pregnant soldier. She perspires more rapidly, helping her body cool more efficiently. However, if her temperature rises above degrees Fahrenheit (F), this could be a fever related to illness, and the soldier should see her health care provider. The major changes that occur in the thermoreglation system include: Basal metabolic rate probably declines in early pregnancy, but then increases steadily during the remainder of the pregnancy -- this affects internal (core) temperature. Core temperature at rest increases. During the first few minutes of vigorous exercise, it actually decreases because pregnant soldiers are more efficient at cooling; however, after that the core temperature increases steadily. A paramount concern during maternal exercise is hydration. ELs must provide a source of water for pregnant soldiers and encourage frequent water breaks. The availability of water to contribute to the cooling process and to ensure an adequate increase in blood volume is a fundamental principle that must be emphasized. The importance of consuming at least two quarts of water or other hydrating fluids per day cannot be over-emphasized. Very active soldiers should be encouraged to drink water until their urine is clear. During hot, humid weather, exercise should only take place in a cooled or air-conditioned room.

Hydration is a major concern during maternal exercise.
WATER, WATER, WATER Hydration is a major concern during maternal exercise. Provide a ready source of water Encourage frequent water breaks Hydration is a major concern during maternal exercise. ELs must provide a ready source of water for pregnant soldiers and encourage frequent water breaks. EMPHASIZE THIS! Water contributes to the cooling process Ensures adequate increase in blood volume Drink before and during and after exercise Consume at least 2 quarts of water or other fluid per day Very active soldiers should drink water until their urine is clear During hot, humid weather, exercise should only be done in a cooled or air-conditioned room.

Insulin resistance Anti-insulin environment is aided by:
placental lactogen Like growth hormone Increases lipolysis and FFA Increases tissue resistance to insulin Increased unbound cortisol Estrogen and Progesterone may also exert some anti-insulin effects

Thyroid Estrogen stimulates Increase in TBG hCG stimulates thyroid
Total T3 and T4 are increased However the active hormones remains unchanged hCG stimulates thyroid TSH is reduced Iodine deficient state Due to Increased renal clearance To rule out pathologic changes Early in pregnancy TSH can be used Later free T4 is needed

Liver Liver morphology unchanged Lab Tests similar to liver disease
Alkaline phosphatase doubles AST, ALT, GGT and bilirubin are slightly lower Decreased plasma albumin

Gallbladder Impaired contraction High residual volumes
Promotion of stasis Stasis associated with increased cholesterol saturation of pregnancy, supports predisposition of stones Intrahepatic cholestasis Retained bile salts-pruritus gravidarum

Physiologic changes - INTEGUMENTARY SYSTEM These result from stretching of the skin and hormonal changes Linea nigra: pigmentation down middle line of abd Chloasma – “mask of pregnancy” Straie: stretch marks of abd, breasts, thighs and buttocks Sweating These result from stretching of the skin and hormonal changes Linea nigra – pigmentation down middle line of abd, more notic in darker skinned and women of color Chloasma - brownish pigmentation of face Straie – stretch marks of abd, breasts, thighs and buttocks See slide Wajed Hatamleh RN, MSN, PhD. 65

Skin changes Chloasma or melasma gravidarum Striae Linea nigra

Skin Changes Stretch marks
Dark pigmented line on there abdomen which is called Linea Nigra Pigment changes on their face and neck Small blood vessels in the face, neck and upper chest MOST OF THESE RESOLVE AFTER PREGNANCY Stretch marks are common over breasts, abdomen and hips Many woman get a dark pigmented line on the abdomen called a Linea Nigra which resolves after pregnancy Occasionally, women will have pigment changes on their face and neck. This also resolves after pregnancy. Small blood vessels may appear in the face, neck, and upper chest. These are more common in white women and less common in women of other skin colors. These usually resolve after pregnancy.

Melasma

Melasma Also known as the mask of pregnancy
More common in dark skin people More pronounced in the summer Fades a few months after delivery Repeated pregnancy can intensify Can occur in normal non-pregnant women with harmless hormonal imbalances or women on OCPs or depo

Striae

Striae Reddish slightly depressed Breasts, thighs, and abdomen
In future pregnancies they appear as glistening, silver lines

Linea nigra

Hyperpigmentation Melasma and linea nigra Estrogen and progesterone
Some melanocyte stimulating effect

Breast Changes Early in pregnancy, tenderness and tightness is common
After 8 weeks, breasts grow and blood vessels often are visible To help with breast discomfort: Wear supportive bra that does not bind Avoid under-wire bras Wear bra day and night Use warm soaks or warm showers Nipples become larger and darker A thick yellowish fluid can be expressed from the nipple

MS system Joint relaxation Posture changes -lordosis/center of gravity Back ache Diastasis recti: separation of rectus abdominous Leg cramp due to calcium, and stretching Posture changes-lordosis/center of gravity Relaxin (placenta) softens all joints Rectus abdominous can separate Low back pain, side pain etc Leg cramps/stretching and Calcium Wajed Hatamleh RN, MSN, PhD. 76

Pelvic Floor Muscle Functions
Maintain alignment and support of internal organs Control of urine flow Sexual enhancement Eliminate waste from rectum Improve recovery from episiotomy The pelvic floor muscles have several functions: Maintain alignment and support of the internal organs. Control of urine flow. Sexual enhancement. Eliminate waste from the rectum. If the pelvic floor is weak, it can contribute to: Fall of the bladder or uterus through the pelvic floor muscles due to lack of support. Stress incontinence (uncontrollable leakage of urine especially during exercise or when coughing or sneezing). Limited sexual pleasure during intercourse. Delayed recovery of tissue in the case of an episiotomy (i pi ze ot’ o me). An episiotomy is a cut of the pelvic floor during delivery.

Uterus & Uterine Ligaments
The uterus is a hollow bag of involuntary muscle. The non-pregnant uterus weighs slightly more than two ounces. It is the size of a pear and can hold approximately two teaspoons of fluid. In pregnancy, the uterus grows to a weight of about 2.5 pounds and has a capacity of approximately 1.5 to 2.5 gallons. It enlarges through the stretching of muscle fiber to the size of a watermelon. The muscle fibers lengthen 7-11 times and widen 2-7 times. It also increases the number and size of its blood vessels and nerves. After the first trimester (first 13 weeks of pregnancy), the uterus begins to prepare for labor and delivery by contracting involuntarily and irregularly. These are called Braxton-Hicks contractions. They are: prelabor contractions that work toward shortening and widening the cervix and stretching the bottom of the uterus soften the cervix and prepare it for labor do not increase in length, frequency, or the intensity associated with labor usually are not painful but can be uncomfortable In labor, the uterus contracts with increasing frequency and intensity and pushes the baby through the birth canal. The uterine ligaments hold the uterus in place and undergo prolonged stretching during pregnancy. The round ligaments attach the uterus to the pubic bone in the front and help maintain the uterus in the center of the pelvis. Either a sharp pain or a dull ache near the hip joint is common when they are stretched upward. To relieve the discomfort: Bend into the pain at the hip joint so that the ligament is shortened and tension relieved. Support your abdomen when changing positions Tighten abdomen and buttocks to support uterus Use legs to lift Get a maternity support Wear flat shoes If pain continues, the soldier should check with her health care provider. The broad ligaments connect the uterus to the sacrum and are often involved in backaches during pregnancy. Pain in the low back is the result of weak abdominal muscles, poor posture, and the weight of the abdomen pulling on the back ligaments. Broad ligament Round ligament

Biomechanical Changes
Weight distribution shifts Joint movement Balance of muscle strength Spinal curves increase Joint laxity becomes greater More structural discomfort Increased potential for nerve compression Biomechanics includes the bones and muscles, and how they work together to make the body move. The brain receives a continuous supply of information about the changing posture of the pregnant body and eventually accepts the altered arrangement and balance of body parts. Feedback from the skin, joints, and muscles are involved in this process. By the end of pregnancy, the brain has re-configured its image of the body in balance. The major changes that occur with respect to biomechanics include: The change in the center of gravity as the baby grows in size during the second half of pregnancy. This is one of the most significant changes in the body. The center of gravity changes from the center of the pelvis with surrounding body weight evenly distributed in all directions to a point forward and slightly up from the center of the pelvis. The increased weight positioned forward of the pelvic midpoint causes forward gravitational pull. Movement of joints due to changes in weight distribution (more weight on one side of a joint than the other, when it was balanced before). Balance of muscle strength changes around the joint to accommodate the new weight distribution. To compensate for the forward gravitational pull, the soldier's posture changes to maintain a balanced erect position. The back of the waist curves in, the top of the pelvis tilts forward and the curves in the upper spine increase. These changes put stress on muscles and joints. Spinal curves increase, placing a greater load on the vertebrae. Joint laxity causes a greater risk for injury. Hormone changes (increased levels of relaxin and elastin) that affect the looseness of ligaments and tendons make the joints more mobile. Although this helps with the birth of the baby, it can stress joints and muscles during movement. There can be more structural discomfort such as low back pain. There is increased potential for nerve compression and blood vessel entrapment, such as sciatica (si at’ ik a) (chronic pain in the lower back and hip radiating down the leg) or carpal tunnel syndrome (increased pressure on the nerves at the wrist).

Potential for Injury Nerve compression syndromes
During pregnancy and postpartum, the potential for injury to the soldier's neuro-musculo-skeletal structure is increased. Shifts in the center of gravity forward and slightly up destabilize her posture and re-align the carriage of weights and forces through her joints. This shift in center of gravity predisposes nerves, muscles, bones and connective tissues to injury. Strength and flexibility exercises are commonly used to help with joint discomfort. In addition, balancing strength and elasticity among the muscles that control a given joint tends to balance and protect the joint. Pregnant soldiers are particularly subject to 2 nerve compression syndromes: carpal tunnel syndrome and sciatica. Methods to alleviate these problems during pregnancy include: Stabilize and elevate the affected part. Avoid weight bearing on the affected part. Avoid extreme range of motion. Perform special exercises designed to release those areas. PPPT has exercises that address nerve compression syndromes. For arm, wrist, or hand problems, include movements that gently open the front of the chest and shoulder, balance the shoulder joint and upper spine and reduce compression on the arm nerves. If edema in the wrist is a factor, bring the thumb and little finger together. This creates a pocket of space at the inside of the wrist to relieve compression on nerves and blood vessels. During relaxation, it is also useful to focus on releasing the muscles around the joints in the cervical spine, upper back, chest and shoulder for carpal tunnel syndrome. Many soldiers report low back discomforts or pelvic pain. They often describe a feeling of a "hitch", "slippage," or "catching" in the sacro-iliac (SI) joint region. Such movements as pelvic tilts, rocks and rotations in a variety of starting postures, in addition to deep abdominal strengthening, have all been useful in relieving this joint dysfunction. The use of the pelvic tilt exercise is helpful in relieving pelvic ligament pain and strengthens the abdominals. It is advisable to refer all low back and pelvic complaints to a health care provider for consultation. For SI joint slippage or severe sciatica (sciatic nerve impinged and swollen), see a physical therapist or other qualified body work professional. For less severe symptoms, the piriformis stretch and release exercises are helpful. During relaxation, it is also useful to focus on releasing the muscles surrounding the lumbar spine, sacro-iliac and iliofemoral joints for sciatica. Another discomfort that is seen is upper back fatigue, due to increasing kyphosis (hunch backed) and the weight of enlarging breasts. It is critical to make sure there is no underlying medical or neurological problem. If not, a strengthening program will be very helpful. This situation can be aggravated following birth if the strength to maintain healthy spine alignment is not developed, because nursing reinforces the hunched posture. Another difficulty that must be taken into account is the effect of changing alignment on the lower extremity, especially the knees. Lower leg pain often occurs in the latter stages of pregnancy and postpartum, due to mainly to biomechanics. While increases in hormone-related laxity of the knee ligaments during pregnancy does occur, minimal to moderate weight-bearing exercise does not result in any further increase in laxity. Therefore, minimal to moderate weight-bearing exercise is considered safe for healthy pregnant soldiers. The integrity of the pelvic floor is critical to soldiers. Two issues emerge in relation to pelvic floor function associated with exercise. One is the occurrence of incontinence. Urinary incontinence may be affected by congenital defects in the bladder or smooth muscle malfunction. Incontinence may also occur in competitive female athletes or as a result from specific damage to muscles, fascia and nerves of the pelvic floor during childbirth. The second issue is pelvic floor muscle exercises to prevent, rehabilitate or decrease trauma to the pelvic floor – particularly in relation to birth – and its consequences to related organs: the uterus, rectum, and bladder. Potential for Injury Nerve compression syndromes Low back discomforts or pelvic pain Upper back fatigue Lower extremity Pelvic floor function

Postural Dynamics Increased curve of the waist
Top of pelvis tilts forward More flexion in the hip joint Increased hunching in the upper back and neck Tailbone is pushed back This figure helps show how postural changes affect the pregnant soldier’s body. As the weight shifts forward, the body's weight is carried more by the arch of the foot during pregnancy than by the ankle. This, coupled with softening ligaments, often leads to the pregnant soldier having foot discomfort and swollen feet. The specific changes in bony alignment include Increased lumbar lordosis (back of waist curves in). Anterior pelvic tilt (top of pelvis tilts forward). Flexion in the iliofemoral joint (hip joint is flexed more). Increased kyphosis (thoracic spine curve) and cervical (neck) curve. Coccyx or tailbone is pushed back (this is occasionally broken during delivery). NOTE: Have participants practice standing in this exaggerated posture to see how uncomfortable it is. Causes of low back pain include poor posture, loss of abdominal tone, stretched and thinned muscles, changes in body weight distribution, shift in center of gravity, increased muscle tension due to stress/worry about pregnancy, incorrect body mechanics in daily activities, incorrect technique with exercise, and increased joint laxity (looseness) Good posture is important to prevent low back pain. Bad posture looks like this: Neck sags, chin pokes forward and body slumps Slouching cramps the rib cage and makes breathing more difficult Slack muscles produce hollow back-pelvis tilts forward Pressed back strains joints, pushes pelvis forward Weight on inner feet strains arches Good posture looks like this: Straighten neck, tuck chin Body lines up Lift up through rib cage and pull back shoulders Roll arms out Contract abs to flatten back Tuck buttocks under and tilt pelvis back Bend to ease body weight over feet Distribute body weight through center of each foot Help for low back pain: Keep back aligned over hips Avoid twisting and bending at waist Wear comfortable, low-heeled shoes Avoid standing for long periods Get back rubs Use a firm mattress Pelvic rocking exercises

Muscles Affected Overstretching & weakening of gluteal muscles & hamstrings Overstretching & weakening of abdominal muscles & pelvic floor Overstretching & weakening of upper back muscles Shortening and tightening of low back & hip flexors muscles Shortening of upper back flexors & pectoral muscles Biomechanical changes cause the following muscle shifts: Overstretching and weakening of gluteal muscles and hamstrings (buttocks and back of leg). Overstretching and weakening of abdominal muscles and pelvic floor muscles. Overstretching and weakening of upper back muscles (shoulders forward). Shortening and tightening of low back and hip flexor muscles. Shortening of upper back flexors and pectoral muscles (chest caves in). The first step in preventing injury is to ensure that the physics of pregnancy is accounted for in the design of individual exercises in order to counter the effects of gravity on the pregnant posture. During a pregnancy exercise session, these are the ways the exercises you teach will help relieve structural stresses. Centering activities promote efficient alignment. Physical balance is one of the components of centering. Unbalanced muscles place demands on the skeletal muscles causing fatigue as they maintain upright posture as well as cause movement. When joints are balanced, contractions of deep muscle fibers nearest the joint centers are the primary righting mechanism. When balanced and relaxed, the individual is centered. Strengthening muscles that are overstretched (hamstrings, gluteals, abdominals and upper back). Stretching muscles that are shortened (hip flexor, low back and chest, quadriceps). Resting in the side-lying position when muscle fatigue occurs (after appropriate cool down) or supine constructive rest position for postpartum. Help for Leg cramps: Can be caused by decreased potassium or calcium. Eating a banana and calcium supplements each day can help Standing on a flat surface and stretching each calf can help If cramping is in one leg, associated with a red warm area and persists contact your health care provider immediately

Neurological and sensory
Decreased intraoccular pressure Corneal thickening Altered sense of smell Decreased attention span Problems with memory Altered CNS physiology leading to mood disturbance. Wajed Hatamleh RN, MSN, PhD.

Combat Effects of Gravity/ Hormones
Do pelvic tilts Alter the stance Shorten the jog stride Lower or eliminate the step in aerobics Avoid rapid leg abduction Avoid breast stroke kick in swimming Recognize tolerance for activities will vary Do pelvic floor exercises to prevent trauma Emphasize strengthening & stretching exercises Wear abdominal support/ sports bra when exercising for support Use techniques and make exercise modifications that help combat the effects of gravity and hormonal changes. A pregnant soldier's body has more potential for injury from the effects of ligament laxity. Muscle and bone adaptations require increased energy to maintain balance and produce movement. To counteract the decreased mechanical advantage, the following should be included: Use pelvic tilts to help relieve low back discomfort and maintain more normal alignment. Alter the stance – some soldiers prefer feet further apart in later pregnancy. Shorten the jog stride. Lower the step, if doing step aerobics, and eliminate the step in the third trimester. Avoid rapid leg abduction (leg moves outward) if the pubic area is sensitive. Avoid breaststroke kick when swimming if pubic area or groin is sensitive. Recognize that the impact of weight-bearing activities varies- some soldiers will tolerate running, step aerobics, etc., while others may not be able to do so. Kegels and birth squats may help prevent pelvic floor trauma. Strengthen the gluteal muscles, hamstrings, and quadriceps for hip and leg strength. Strengthen the abdominal and pelvic floor muscles. Strengthen the upper back muscles. Stretch the low back and hip flexor muscles. Stretch the chest muscles. Lengthen the spine.

Changes to Body System First Trimester Second Trimester
Baby begins to grow Increased urination Changes with skin and hair Thickening waistline Nausea/fatigue Second Trimester Baby’s weight increases Energy level improves Heartburn Leg cramps Pelvis relaxes causing SI discomfort Third Trimester Baby has more rapid growth & weight gain Backaches Swelling of the hands, legs, and feet Breathlessness More frequent urination In summary, pregnancy alters the body from head to toe. The effects of these changes vary as the pregnancy progresses through the trimesters. In the first trimester, the baby begins to grow and the mother experiences increased urination, changes in skin and hair, and a thickening waistline. Changes in the cardiovascular system and metabolism can cause nausea and fatigue. In the second trimester, the baby's weight increases from an ounce to more than a pound. The pregnant soldier’s energy level improves, but she may experience heartburn, leg cramps, and her pelvis may relax causing discomfort to her sacro-iliac joint. During the third trimester, the baby has more rapid growth and weight gain. The pregnant soldier may have backaches, swelling of the hands, legs, and feet, and may feel warmer. She may experience breathlessness and more frequent urination as additional weight is placed on the bladder. Most changes that occur will be normal and will go away after delivery.

Physiologic changes of pregnancy

Similar presentations

Presentation on theme: "Physiologic changes of pregnancy"— Presentation transcript:

Similar presentations

About project

Feedback

Log in

Auth with social network:

Physiologic changes of pregnancy

Similar presentations

Presentation on theme: "Physiologic changes of pregnancy"— Presentation transcript:

Similar presentations

About project

Feedback