Maternal Physiology of Pregnancy Jason K. Baxter, MD, MSCP Medical Director, Inpatient Obstetrics...
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Transcript of Maternal Physiology of Pregnancy Jason K. Baxter, MD, MSCP Medical Director, Inpatient Obstetrics...
Maternal Physiology of Pregnancy
Jason K. Baxter, MD, MSCPMedical Director, Inpatient Obstetrics
Director, Division of ResearchDepartment of Obstetrics and Gynecology
Division of Maternal-Fetal [email protected]
Maternal Physiologic Changes
HormonalBreastsCardiovascularHematologicRespiratory
GastrointestinalUrinaryReproductive TractMusculoskeletalDermatologic
Hormonal (-HCG)Produced in the syncytiotrophoblasts of the
placentaStimulates corpus luteum to produce
progesterone and estradiol Doubles every 48 hrs in first trimester
Hormonal (cont’d)
Progesterone Maintains pregnancy Produced by corpus luteum Placenta takes over at 9 weeks Relaxation of smooth muscle
HPL: Diabetogenic stateThyroidProlactin increased
Breasts
Enlarge (first sign)Ducts (estrogen)Areoli (progesterone)Prolactin
CardiovascularCardiac Output = Stroke Volume x Heart Rate
Increase:(30-50%) (20-35%) (5-15%) As early as 10 weeks
Cardiovascular (cont’d)
Increased blood flow Uterus Breasts Skin Kidneys
Peripheral vascular resistance decreases
Cardiovascular (cont’d)BP = CO x SVR Inferior vena cava
(supine hypotension) syndrome
Elevated venous pressure in lower extremeties
Varicose veins Venous stasis Leg edema Thrombi Hemorrhoids
Cardiovascular (cont’d)
Displaced upward and leftEKG: Left axis deviationChest X-ray: cardiomegalyHyperdynamic state
Systolic ejection murmurs S3 gallop Distended neck veins
HematologicBlood Volume Increases 30–40 % (1500cc)Hemodilution of pregnancy
“Physiologic anemia”
Hematologic (cont’d)
Iron stores decrease Actively transported to fetus 1000mg additional iron needed
Increased WBCsDecreased platelets
Hematologic (cont’d)
Hypercoaguable state Thromboembolism risk
• x 2 in pregnancy
• x 5.5 in puerperium
Respiratory
Mechanical changesUpper airway
Mucosal congestion, edema
Chest wall Increased AP diameter Flaring of the ribs Elevated diaphragm
Respiratory (cont’d)MV = TV x RR Increased tidal volume
(40%)HyperventilationMild, compensated,
respiratory alkalosisPhysiologic dyspnea
GastrointestinalDecreased GI motility and tone
Delayed gastric emptying time Constipation
• Hemorrhoids
Poor esophageal tone Incompetence of esophageal/ stomach sphincter
• Gastric reflux
• Heartburn
Gastrointestinal (cont’d)Cholestasis Increased liver metabolism
Alkaline Phosphatase Cholesterol Fibrinogen TBG
Hypoalbuminemia Decreased colloid oncotic pressure
Epulis of pregnancy
Urinary
Renal blood flow and glomerular filtration rate increase 40-50%
Increased renin/ angiotensin systemIncreased urinary frequency
Enlarging uterus Decreased bladder capacity
Hydronephrosis and hydroureter
Smooth-muscle relaxing progesterone
Dextrorotation of uterus over right pelvic brim
Stasis and risk of infection• Cystitis
• Pyelonephritis
Reproductive Tract
Uterus Distends to 1000 times its normal volume 20% of cardiac output (500ml/min) at term
Vagina Increased vascularity and distensibility Leukorrhea of pregnancy
Reproductive Tract (cont’d)
Cervix Ectropion
Musculoskeletal
Altered center of gravityProgressive lumbar lordosis Relaxin
Ligamentous symphysis pubis
Diastasis RectiCarpal tunnel syndromeSciatica
DermatologicIncreased pigmentation Increased estrogen and progesterone Increased melanocyte-stimulating hormoneAreola, linea nigra, perineum, melasma/chloasma
Dermatologic (cont’d)Striae gravidarum (stretch marks)Vascular spiders (telangiectasias)Palmar erythemaHirsutism and acne (progesterone)
Dermatologic (cont’d)Pruritus gravidarum (elevated bile salts)Pruritic and urticarial papules and plaques
of pregnancy (PUPPP)
Maternal Physiology in PregnancyHormonal: Progesterone relaxes smooth muscleBreasts: Enlarge and develop milk
productionCardiovascular: Hyperdynamic stateHematologic: Hypercoaguable stateRespiratory: Respiratory alkalosisGastrointestinal: Decreased motilityUrinary: Urinary stasisReproductive: Distensibility & hypertrophyMusculoskeletal:Center of gravity changed & relaxinDermatologic: Increased pigmentation