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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 [insert presenter info] Anatomical Changes Pelvis Pelvic Floor Muscles Uterus Uterine Ligaments Cervix Placenta Amniotic Fluid Pelvis Pelvic Floor Muscles Abdominal Diastasis Normal Diastasis Physiological Changes Circulatory Urinary Thermoregulation Skin Metabolic Breasts Respiratory Biomechanical Digestive 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 stores free fatty acids from maternal RELAXIN Released by corpus luteum then the Placenta Softens pelvic ligaments Reduces myometrial tone Changes to Body System First 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 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 Cardiovascular Changes INCREASE DECREASE Blood volume Hematocrit Cardiac (heart) output Blood pressure Blood supply to uterus Stroke volume Cardiac reserve End diastolic volume Vascular resistance Resting pulse % of blood plasma 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 10-14 g/dL later in pregnancy Decreased Hct (38-47%) Normal pregnancy Hct is 32-42 later in pregnancy Pulse rate may increase 10-15 beats. Weight of uterus can cause supine hypotensive syndrome. Wajed Hatamleh RN, MSN, PhD. 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 50-70 % RBC mass increases 20-35 % Beginning by the 6th wk 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 diaphragm Consumption Increase in needed oxygen Stimulation Progesterone stimulation Respiratory Changes Respiratory capacity increases Shortness of breath Pulmonary reserve decreases Increased risk of muscle soreness Tendency to hyperventilate RESULT adjust the intensity level and duration of exercise Physiologic changes RESPIRATORY increase SYSTEM respiratory rate increased oxygen consumption common are nasal stuffiness, nosebleeds due to Increased vascular swelling to nose 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 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. 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 Digestive Changes Digestive system slows Intestines are pushed up and to the sides Smooth muscle of the stomach relaxes and can cause heartburn Constipation and hemorrhoids are common during pregnancy Morning sickness Physiologic changes METABOLISM BMR increases by 20-25 % during pregnancy Recommended weight gain – 25-35 lb – 15-25 lb Underweight – 25-35 lb Overweight Need for increased iron, calcium, 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 Genital Tract Increased vascularity and hyperemia 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 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 elongates during the 1st 10 weeks like a stalk Isthmus From Later 7mm to 2.5cms at 10 weeks 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 ND 2 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 rd TRIMESTA 3 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 Red volume: from 5 litres to 7.5 total volume up by 40-50% 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 32-34 weeks then maintained 50% rise in plasma volume 20% rise in red cell mass Heamodilution: Physiological anaemia Most apparent at 32-34 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 Physiologic changes URINARY TRACT Increased glomerular filtration rate Frequency Infection : Smooth muscle of bladder relaxes/stasis Wajed Hatamleh RN, MSN, PhD. Endocrine Normal pregnancy physiology shows Postprandial hyperglycemia Early switch from glucose to lipids for fuels Insulin resistance promotes hyperglycemia To ensure sustained glucose levels for fetus Accelerated starvation “lower lows and higher highs” Resistance-Reduced peripheral uptake of glucose for a given dose of insulin Mild fasting hypoglycemia occurs with elevated FFA, triglycerides,and cholesterol WATER, WATER, WATER Hydration is a major concern during maternal exercise. Provide a ready source of water Encourage frequent water breaks 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 TSH is reduced Iodine deficient state Total T3 and T4 are increased However the active hormones remains unchanged 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 Wajed Hatamleh RN, MSN, PhD. 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 Melasma 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 Nipples A thick become larger and darker 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 Wajed Hatamleh RN, MSN, PhD. Pelvic Floor Muscle Functions Maintain alignment and support of internal organs Control of urine flow Sexual enhancement Eliminate Improve waste from rectum recovery from episiotomy Uterus & Uterine Ligaments Uterus Round ligament Broad ligament Biomechanical Changes Weight Joint distribution shifts movement Balance Spinal of muscle strength curves increase Joint laxity becomes greater More structural discomfort Increased potential for nerve compression 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 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 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 Changes to Body System First Trimester Third 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 Baby has more rapid growth & weight gain Backaches Swelling of the hands, legs, and feet Breathlessness More frequent urination