IN THE NAME OF ALLAH. Maternal Physiology DR B. Khani

IN THE NAME OF ALLAHIN THE NAME OF ALLAH

Maternal PhysiologyMaternal Physiology

DR B. KhaniDR B. Khani

Maternal changes during pregnancy

The maternal system may produce a

series of changes in order to adapt to the

needing of fetal growth and development

influenced by placenta hormone and

neuro-endocrine

Changes of reproductive system

Uterus

Body: become enlargement and soft

from 7×5 ×3cm pre-pregnancy to

35×25 ×22cm at term .

Volume of uterus cavity:

become enlargement from 10ml pre-pregnancy to 5000ml at term .

Weight: be increased from 70g pre- pregnancy

to 1000g at term .

Blood supply: blood flow increased

significantly .

upto 500- 700ml/min,increased 4-6 times and

most of blood flow is transported to the

placenta(80-85%) .

Isthmus: be dilated and become soft from 1cm

pre-pregnancy a portion of the uterus

after 12 gestational weeks

Cervix: be soft and coloration or stain

secrete amount of mucus avoiding the

uterus cavity suffer from infection

Changes of ovary Stop ovulation .

Corpus luteum formation and maintains for

7-10 weeks .

The function of corpus luteum is

substituted by the placenta .

Corpus luteum atretic gradually after 3-4

months gestation.

Cardiovascular systemCardiovascular system

1.1. Heart:Heart: move upward and left.move upward and left.

2.2. Cardiac Output Cardiac Output increase by 30%, reach to peak at 28increase by 30%, reach to peak at 28ndnd –32 –32thth

weekweek

3.3. Blood pressureBlood pressure early or mid pregnancy Bpearly or mid pregnancy Bp↓.↓.late pregnancy late pregnancy

Bp↑ .Supine hypotensive syndromeBp↑ .Supine hypotensive syndrome

Cardiac OutputCardiac Output

Cardiac OutputCardiac Output

Maternal cardiac output is highest in which Maternal cardiac output is highest in which position?position?

lateral recumbentlateral recumbent

Lowest?Lowest?

StandingStanding

Vascular ChangesVascular Changes

SVR decreases until mid-pregnancy, then SVR decreases until mid-pregnancy, then rises slightly but remains 20% below non-rises slightly but remains 20% below non-pregnant valuespregnant values

BP follows in parallel, especially DBP(10-BP follows in parallel, especially DBP(10-15 mmHg)15 mmHg)

SBP: 5-10 mmHg SBP: 5-10 mmHg

SVR ChangesSVR Changes

Respiratory PhysiologyRespiratory Physiology

Conformational changes in chest:Conformational changes in chest:

– Transverse diameter increases 2 cmTransverse diameter increases 2 cm

– Circumference increases 5-7 cmCircumference increases 5-7 cm

– Diaphragm rises 4 cm; excursion increases 1-Diaphragm rises 4 cm; excursion increases 1-2 cm2 cm

The Respiratory systemThe Respiratory system

• Respiratory rate: no changeRespiratory rate: no change

• vital capacity: no changevital capacity: no change

• Tidal volume: Tidal volume: ↑↑ 40% 40%

• Functional residual capacity:Functional residual capacity:↓↓

• OO22 consumption: consumption: ↑↑ 20% 20%



FEV1 is unchangedFEV1 is unchanged

TV increases about 40%; since RR is TV increases about 40%; since RR is unchanged, that increases minute unchanged, that increases minute ventilation 40%ventilation 40%

Increased MV leads to:Increased MV leads to:– Increased alveolar oxygenIncreased alveolar oxygen– Slightly increased arterial oxygen (101-108)Slightly increased arterial oxygen (101-108)– Decreased alveolar and arterial CO2 (27-32)Decreased alveolar and arterial CO2 (27-32)

Hematologic ChangesHematologic Changes

Blood Volume increases by?Blood Volume increases by?

40-50%40-50%

Peaks at?Peaks at?

30-34 weeks30-34 weeks

RBC Mass increases?RBC Mass increases?

20% without iron supplementation20% without iron supplementation

30% with iron supplementation30% with iron supplementation



What are the total iron demands for a What are the total iron demands for a normal term pregnancy in a woman normal term pregnancy in a woman without preexisting iron depletion?without preexisting iron depletion?

1000 mg :1000 mg :– 300 mg fetus and placenta300 mg fetus and placenta– 500 mg maternal red cell increase500 mg maternal red cell increase– 200 mg compensate for normal daily losses200 mg compensate for normal daily losses

Translates into required daily absorption of Translates into required daily absorption of 3.5 mg.3.5 mg.


Iron demands increase in later gestation Iron demands increase in later gestation (6-7 mg/day near term)(6-7 mg/day near term)

About 10% of ingested iron is absorbed About 10% of ingested iron is absorbed under conditions of normal iron demands; under conditions of normal iron demands; can increase when depletedcan increase when depleted

Iron supplementation is needed to avoid Iron supplementation is needed to avoid iron depletion during pregnancyiron depletion during pregnancy


Mild decrease in mean platelet countMild decrease in mean platelet count– Increased platelet destructionIncreased platelet destruction– DilutedDiluted

Up to 8% will have gestational Up to 8% will have gestational thrombocytopeniathrombocytopenia– Platelet count 70-150,000/mmPlatelet count 70-150,000/mm33

– No increased bleeding complicationsNo increased bleeding complications– Return to normal after deliveryReturn to normal after delivery


Mean WBC count increases Mean WBC count increases – 11stst trimester 8000 (5100-9900) trimester 8000 (5100-9900)– 22ndnd and 3 and 3rdrd trimester 8500 (5600-12200) trimester 8500 (5600-12200)– In labor may rise to 26,000-30,000In labor may rise to 26,000-30,000

T helper 1 and natural killer cells T helper 1 and natural killer cells decrease, T helper 2 increase (cell-decrease, T helper 2 increase (cell-mediated immunity mediated immunity humoral immunity) humoral immunity)

Decreased concentrations of IgG, IgM, IgADecreased concentrations of IgG, IgM, IgA

Coagulation SystemCoagulation System

Procoagulant factors increasedProcoagulant factors increased– (factors I, VII, VIII, IX, X).(factors I, VII, VIII, IX, X).

Natural inhibitors of coagulation decreasedNatural inhibitors of coagulation decreased

Decreased fibrinolysisDecreased fibrinolysis– Reduced plasminogen activatorReduced plasminogen activator

Defense against puerperal hemorrhageDefense against puerperal hemorrhage

Increased risk of thromboembolismIncreased risk of thromboembolism

GI PhysiologyGI Physiology

Common symptoms: heartburn, increased Common symptoms: heartburn, increased appetiteappetite

Constipation may be increased Constipation may be increased

Overall inhibition of GI motilityOverall inhibition of GI motility

Many physiologic changes attributed to Many physiologic changes attributed to progesteroneprogesterone


EsophagusEsophagus

– no change in motilityno change in motility

– reduced LES resting pressure (decreases reduced LES resting pressure (decreases with gestational age)with gestational age)


StomachStomach– Conflicting data on acid production, gastric Conflicting data on acid production, gastric

emptyingemptying– Davison (1970) showed a longer total Davison (1970) showed a longer total

emptying time but no difference in 30 minute emptying time but no difference in 30 minute volume; changes more pronounced in women volume; changes more pronounced in women with heartburn or in laborwith heartburn or in labor

– Slowed emptying during labor due in part to Slowed emptying during labor due in part to analgesic and sedative useanalgesic and sedative use


IntestinesIntestines– Increased transit time shown in multiple Increased transit time shown in multiple

studies, probably progesterone-mediatedstudies, probably progesterone-mediated– Theoretical changes in absorption related to Theoretical changes in absorption related to

slower transit time and longer exposure of slower transit time and longer exposure of intestinal contents to the mucosaintestinal contents to the mucosa

could be beneficial - allow more time for absorptioncould be beneficial - allow more time for absorption

could be detrimental - allow bacterial overgrowthcould be detrimental - allow bacterial overgrowth

Hepatic PhysiologyHepatic Physiology

Increased protein synthesis (estrogen Increased protein synthesis (estrogen effect)effect)– increased clotting factors, binding globulinsincreased clotting factors, binding globulins– hemodilution decreases albumin hemodilution decreases albumin

concentrationconcentration

50% of normal pregnancies have dilated 50% of normal pregnancies have dilated esophageal veins (portal-systemic shunt)esophageal veins (portal-systemic shunt)Hepatomegaly is abnormal; palmar Hepatomegaly is abnormal; palmar erythema and spider veins commonerythema and spider veins common


Normal values for AST, ALT, GGT, and Normal values for AST, ALT, GGT, and bilirubin are lower in uncomplicated bilirubin are lower in uncomplicated pregnancies than the normal non-pregnant pregnancies than the normal non-pregnant laboratory reference rangelaboratory reference rangeAbnormal LFT seen in 54% with Abnormal LFT seen in 54% with preeclampsia and 14% with PIHpreeclampsia and 14% with PIHHigher LFT: more proteinuria, lower Higher LFT: more proteinuria, lower platelets, more maternal complicationsplatelets, more maternal complications


NPNP 11stst 22ndnd 33rdrd

AST AST (U/L)(U/L)

7-407-40 10-2810-28 11-2911-29 11-3011-30

ALT ALT (U/L)(U/L)

0-400-40 6-326-32 6-326-32 6-326-32

Bili Bili ((μμmol/L)mol/L)

0-170-17 4-164-16 3-133-13 3-143-14

GGT GGT (U/L)(U/L)

11-5011-50 5-375-37 5-435-43 3-413-41

The urinary systemThe urinary system

• KidneyKidney1)1) Renal plasma flow (RFP):Renal plasma flow (RFP):↑↑35%35%2)2) Glomerular filtration rate (GFR):Glomerular filtration rate (GFR):↑↑ 50% 50%

• Ureter : dilutedUreter : diluted • Bladder : Frequent micturationBladder : Frequent micturation• Urine analyzeUrine analyze

EndocrineEndocrine

Pituitary (hypertrophy)Pituitary (hypertrophy)1)1) LH/FSH: LH/FSH: ↓↓2)2) PRL:PRL:↑↑3)3) TSH and ACTH:TSH and ACTH:↑↑ ThyroidThyroid1)1) enlarged (TSH and HCGenlarged (TSH and HCG↑↑))

2)2) thyroxinethyroxine↑↑ and TBG and TBG↑↑ →→ free T free T33 T T44 unchanged unchanged

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IN THE NAME OF ALLAH. Maternal Physiology DR B. Khani