3 IntroductionThe 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.
8 Uterus Non Pregnant Uterus Pregnant Uterus Muscular Structure Almost SolidRelatively thin – walled (≤ 1.5 cm)weight≈ 70 gmApprox gm by the end of pregnancyVolume≤ 10 mL≈ 5 L by the end of pregnancy
9 Mechanism Of Uterine Enlargement Stretching & marked hypertrophy of muscle cells.Considerable increase in elastic tissueAccumulation of fibrous tissue, particularly in the external muscle layer.
10 Uterine size, shape & position First few weeks, original peer shaped organAs 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 CervixAs 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 CervixDuring 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 OvariesCessation 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 RelaxinProtein 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 TubesThe musculature of the fallopian tubes undergoes little hypertrophy.The epithelium of the tubal mucosa becomes somewhat flattened.
16 Vagina & PerineumIncreased 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.
21 ECG Changes Increased heart rate ( 15%) 15° left axis deviation. Inverted T-wave in lead ІІІ.Q in lead ІІІ & AVFUnspecific ST changes
22 Vascular Vascular spider Palmar erythema Minute, red elevations on the skincommon on the face, neck, upper chest,and arms, with radicles branching outfrom a central lesion. The condition is oftendesignated as nevus,angioma, or telangiectasis.Palmar erythemaThe two conditions are of no clinical significance and disappear in most women shortly after pregnancy(estrogen)
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 liters.
25 Pulmonary FunctionThe 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 GastrointestinalPyrosis (heartburn) is common &is caused by reflux of acidic secretions into lower esophagus & decreased tone of sphincter.
27 GastrointestinalIntraesophageal pressure is lower & intragastric pressure is higher in pregnant women.Esophageal peristalsis has lower wave speed &lower amplitude.
28 GastrointestinalGastric 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 HepatobiliarySerum 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 systemStriking 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.
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.
36 NeurologicalWomen often report problems with attention, concentration, &memory throughout pregnancy & early postpartum period.
37 NeurologicalIn 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 3rd trimester un attributable to depression ,anxiety ,sleep deprivation or any other physical changes associated with pregnancy.
38 NeurologicalZeeman 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 MusculoskeletalProgressive 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 MusculoskeletalBones & ligaments of pelvis undergo remarkable adaptationRelaxation of the pelvic joints, particularly symphysis pubisSymphyseal diastasis
41 DermatologicalReddish, slightly depressed streaks commonly develop in the skin of the abdomen and sometimes in the skin over the breasts and thighs.Striae gravidarum
42 DermatologicalThe 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 neckchloasma or melasma gravidarum
44 Weight ChangesMetabolic 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 ChangesThere 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 uterusand its contents, breasts and increase in maternal blood volume and interstitial fluid.
46 OphthalmicDecrease 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 OphthalmicThat’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 DentalGums may become hyperemic & soft during pregnancy and may bleed if mildly traumatized as with a toothbrush.
49 DentalEpulis 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.