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ROBAB DAVAR M.D. 1387 Anatomical and physiological adaptation to pregnancy.

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Presentation on theme: "ROBAB DAVAR M.D. 1387 Anatomical and physiological adaptation to pregnancy."— Presentation transcript:

1 ROBAB DAVAR M.D Anatomical and physiological adaptation to pregnancy

2 بسم الله الرحمن الرحيم

3 Introduction  The anatomical, physiological, and biochemical adaptations to pregnancy are profound.  Many of these remarkable changes begin soon after fertilization and continue throughout gestation, and most occur in response to physiological stimuli provided by the fetus.

4 Mission  Understanding the adaptations to pregnancy.  without such knowledge, it is almost impossible to understand the disease processes that can threaten women during pregnancy and the puerperium.

5 Anatomical adaptations Uterus CervixOvaries Fallopian Tubes Vagina & Perineum Breast

6 Physiological adaptations NeurologicalRespiratoryHematologicCardio VascularGastrointestinalHepatobiliaryUrinaryMetabolicEndocrineMusculoskeletalWeight ChangeDermatologicalOphthalmologicalDental

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8 Uterus Non Pregnant Uterus Pregnant Uterus MuscularStructure Almost Solid Relatively thin – walled (≤ 1.5 cm) weight ≈ 70 gm Approx gm by the end of pregnancy Volume ≤ 10 mL ≈ 5 L by the end of pregnancy

9 Mechanism Of Uterine Enlargement Considerable increase in elastic tissue Stretching & marked hypertrophy of muscle cells. Accumulation of fibrous tissue, particularly in the external muscle layer.

10 Uterine size, shape & position  First few weeks, original peer shaped organ  As pregnancy advances, corpus & fundus assumes a more globular form.  By 12 weeks, the uterus becomes almost spherical.  Subsequently, uterus increases rapidly in length than in width & assumes an ovoid shape.  With ascent of uterus from pelvis, it usually undergoes Dextrorotation (caused by the rectosigmoid colon on the left side).

11 Cervix  As early as 1 month after conception the cervix begins to undergo profound softening &cyanosis due to :  Increased vascularity & edema of the entire cervix.  Hypertrophy & hyperplasia of the cervical glands.  Endocervical mucosal cells produce copious amounts of a tenacious mucus that obstructs the cervical canal soon after conception(mucus plug)

12 Cervix  During pregnancy the basal cells near the squamocolumnar junction are likely to be prominent in size, shape & staining qualities (estrogenic effect).  These changes attribute to the frequency of less than optimal pap smears in pregnant women.

13 Ovaries  Cessation of ovulation & arrest of maturation of new follicles.  Single corpus luteum of pregnancy is found in ovaries of pregnant women that contributes to progesterone production maximally during the first 6 to 7 weeks of pregnancy (4 to 5 weeks postovulation)  This explains the rapid fall in serum progesterone& the occurrence of spontaneous abortion upon removal of the corpus luteum before 7 wks.  Increased diameter of the ovarian vascular pedicle from 0.9cm to approx. 2.6 cm at term.

14 Relaxin  Protein hormone with structural features similar to insulin & insulin like growth factors І,ІІ.  Secreted by corpus luteum, decidua & placenta in a pattern similar to HCG.  Major biological action is remodeling of the connective tissue of reproductive tract, allowing accommodation of pregnancy & successful parturition.  Also secreted by the heart &increased levels found in heart failure (Fisher & co-workers)

15 Fallopian Tubes  The musculature of the fallopian tubes undergoes little hypertrophy.  The epithelium of the tubal mucosa becomes somewhat flattened.

16 Vagina & Perineum  Increased vascularity, hyperemia of the skin & muscles of the perineum & vulva.  Softening of the underlying abundant connective tissue.  Increased vascularity prominently affects the vagina resulting in the violet color characteristic of chadwick sign.  Considerable increase in the thickness of the vaginal mucosa, loosening of the connective tissue, hypertrophy of smooth muscle cells.

17 Breast changes

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19 CardioVascular  Stroke volume  Heart rate  SVR  Systolic BP  Diastolic BP  Mean BP  O2 Consumption ( 30%) ( 15%) ( 5%) ( 10 mmHg) ( 15 mmHg) ( 20%)

20 CardioVascular

21 ECG Changes  Increased heart rate ( 15%)  15° left axis deviation.  Inverted T-wave in lead ІІІ.  Q in lead ІІІ & AVF  Unspecific ST changes

22 Vascular  Vascular spider Minute, red elevations on the skin common on the face, neck, upper chest, and arms, with radicles branching out from a central lesion. The condition is often designated as nevus,angioma, or telangiectasis.  Palmar erythema The two conditions are of no clinical significance and disappear in most women shortly after pregnancy(estrogen)

23 Respiratory

24 Pulmonary Function  The respiratory rate is little changed.  Tidal volume, minute ventilatory volume, and minute oxygen uptake increase significantly as pregnancy advances.  T V by about 40% lead to MVV from 7.25 liters to 10.5 liters.

25 Pulmonary Function  The functional residual capacity (FRC) and the residual volume of air are decreased due to the elevated diaphragm.  Lung compliance remains unaffected.  Airway conductance is increased and total pulmonary resistance is reduced, possibly as a result of progesterone action.

26 Gastrointestinal  Pyrosis (heartburn) is common &is caused by reflux of acidic secretions into lower esophagus & decreased tone of sphincter.

27 Gastrointestinal  Intraesophageal pressure is lower & intragastric pressure is higher in pregnant women.  Esophageal peristalsis has lower wave speed &lower amplitude.

28 Gastrointestinal  Gastric emptying time is unchanged during pregnancy,but during labor and with administration of analgesics prolonged that lead to aspiration.  Reduced motility in small intestine lead to increase time of absorption.  Reduced motility of large intestine lead to increase time for water absorption that predisposes to constipation.

29 Hepatobiliary  No increase in size of the liver of pregnant woman.  There is no distinct changes in liver morphology as evidenced by histological evaluation of postmortem liver biopsies by EM.  Despite this, there is increase in diameter of portal vein &its blood flow.  Liver function tests varies greatly during normal pregnancy.  Serum alkaline phosphatase almost doubles (heat stable placental alkaline phosphatase isozymes).

30 Hepatobiliary  Serum AST,ALT, bilirubin levels are slightly lower than non pregnant normal values.  Serum concentration of albumin decreases.  Decrease in albumin to globulin ratio occurs due to combined reduction in albumin concentration & slight increase in serum globulin levels.

31 Gallbladder changes  Reduced contractility of the gallbladder.  Progesterone impairs gallbladder contraction by inhibiting cholecystokinin-mediated smooth muscle stimulation,primary regulator of gallbladder contraction.  Impaired motility leads to stasis, and this associated with increase cholesterol saturation of pregnancy leads to cholesterol stone in multiparous.  Pregnancy causes intrahepatic cholestasis &pruritus gravidarum from retained bile salts.  Cholestasis of pregnancy is linked to high levels of estrogen which inhibit transductal transport of bile acids,also increased progesterone & genetic factors has been implicated in pathogenesis.

32 Urinary system  Striking anatomical changes are seen in the kidneys and ureters.  This is due to changes in pelvic anatomy and is a feature of 'normal' pregnancy.  Frequency of micturition is a common symptom of early pregnancy and again at term.

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34 Urinary System  A degree of hydronephrosis and hydroureter exists.  loss of smooth muscle tone due to progesterone, aggravated by mechanical pressure from the uterus at the pelvic brim.  VUR is also increased.  These changes predispose to UTI.

35 Urinary system

36 Neurological  Women often report problems with attention, concentration, &memory throughout pregnancy & early postpartum period.

37 Neurological  In a longtudinal study done by keenan &colleagues (1998) investigating memory in pregnant women by a matched control group, they found (pregnancy related decline in memory limited to 3 rd trimester un attributable to depression,anxiety,sleep deprivation or any other physical changes associated with pregnancy.

38 Neurological  Zeeman and co-workers (2003) used MRI to measure cerebral blood flow across pregnancy in 10 healthy women.  They found that mean blood flow bilaterally in the middle and posterior cerebral arteries decreased progressively from 147 and 56 ml/min when non pregnant to 118 and 44 ml/min late in the third trimester, respectively.  The mechanism and clinical significance of this decrease, and whether it relates to the diminished memory observed during pregnancy is unknown.

39 Musculoskeletal  Progressive lordosis compensates for the anterior position of the enlarging uterus.  Increased mobility of sacroiliac, sacrococcygeal &pubic joints(not correlated to increased levels of maternal estrogen, progesterone &relaxin levels.  Joint mobility causes low back pain which is bothersome late in pregnancy.

40 Musculoskeletal  Bones & ligaments of pelvis undergo remarkable adaptation  Relaxation of the pelvic joints, particularly symphysis pubis  Symphyseal diastasis

41 Dermatological  Reddish, slightly depressed streaks commonly develop in the skin of the abdomen and sometimes in the skin over the breasts and thighs. Striae gravidarum

42 Dermatological  The midline of the abdominal skin “linea alba” becomes markedly pigmented, assuming a brownish- black color to form the linea nigra.

43 Dermatological chloasma or melasma gravidarum Irregular brownish patches of varying size appear on the face and neck

44 Weight Changes  Metabolic changes, accompanied by fetal growth, result in an increase in weight of around 25% of the non-pregnant weight.  Approximately 12.5 kg in the average woman.

45 Weight Changes  There is marked variation in normal women but the main increase occurs in the second half of pregnancy and is usually around 0.5 kg per week.  Towards term the rate of gain diminishes and weight may fall after 40 weeks.  The increase is due to the growth of the uterus and its contents, breasts and increase in maternal blood volume and interstitial fluid.

46 Ophthalmic  Decrease in intraocular pressure due to increased vitreous outflow.  Decreased corneal sensitivity especially, late in gestation.  Slight increase in corneal thickness thought to be due to edema.

47 Ophthalmic  That’s why pregnant women may have discomfort with previously comfortable contact lenses.  Increase frequency of Krukenberg spindles (hormonal).  Visual function remains unaffected except for transient loss of accomodation.

48 Dental  Gums may become hyperemic & soft during pregnancy and may bleed if mildly traumatized as with a toothbrush.

49 Dental  Epulis of pregnancy (a focal highly vascular swelling of the gum develops occasionally & regresses spontaneously after delivery.  Most evidence indicates that pregnancy doesn't incite tooth decay.

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