maternal physiology sindhu srinivas, md, msce division of maternal fetal medicine

Maternal Maternal physiologyphysiology

Sindhu Srinivas, MD, MSCESindhu Srinivas, MD, MSCE

Division of Maternal Fetal Division of Maternal Fetal MedicineMedicine

GoalsGoalsTo understand the normal changes associated with To understand the normal changes associated with

pregnancypregnancy

Body WaterBody Water TBW increases from 6.5L to 8.5LTBW increases from 6.5L to 8.5L

At term water content of fetus, placenta and AF At term water content of fetus, placenta and AF is 3.5Lis 3.5L

BV, PV, RBC, extravascular, intracellularBV, PV, RBC, extravascular, intracellular Pregnancy is a condition of chronic volume Pregnancy is a condition of chronic volume

overloadoverload Water retention exceeds Na retention-Water retention exceeds Na retention-

decreased plasma osmolality (Na dec by 3-decreased plasma osmolality (Na dec by 3-4)4)

To recognize physiologic and pathologic states To recognize physiologic and pathologic states during pregnancyduring pregnancy

Hematology – Blood Hematology – Blood volumevolume

Increases progressively from 6 to 8 Increases progressively from 6 to 8 weeks’ gestationweeks’ gestation

maximum volume at 32 weeks - 45% maximum volume at 32 weeks - 45% increaseincrease

possibly due to estrogen stimulation of possibly due to estrogen stimulation of renin-angiotensin-aldosterone systemrenin-angiotensin-aldosterone system

(Inc Prog, NO->Dec SVR->Dec MAP-(Inc Prog, NO->Dec SVR->Dec MAP->Inc Na retention)>Inc Na retention)

Hematology – RBC massHematology – RBC mass

Red blood cell mass Red blood cell mass increases by 250-450 cc by increases by 250-450 cc by termterm

Increased productionIncreased production Possibly hormonally Possibly hormonally

mediatedmediated

Hematology - IronHematology - Iron Maternal requirement is Maternal requirement is

1000mg 1000mg normal pregnant woman needs to normal pregnant woman needs to

absorb about 3.5 mg/day of ironabsorb about 3.5 mg/day of iron

the goal of iron supplementation the goal of iron supplementation is to prevent maternal iron is to prevent maternal iron deficiencydeficiency

iron is actively transported to iron is actively transported to the fetusthe fetus

Hematologic changesHematologic changes IMPLICATIONSIMPLICATIONS

The increase in plasma volume and rbc The increase in plasma volume and rbc mass translates into a 45% increase in mass translates into a 45% increase in circulating blood volumecirculating blood volume

may protect from hemodynamic may protect from hemodynamic instabilityinstability

may serve to dissipate fetal heat may serve to dissipate fetal heat production and provide increase renal production and provide increase renal filtrationfiltration

physiologic anemia of pregnancyphysiologic anemia of pregnancy may function to decrease blood viscositymay function to decrease blood viscosity may improve intervillous perfusion?may improve intervillous perfusion?

HematologyHematology LEUKOCYTESLEUKOCYTES

Peripheral wbc rises progressively during Peripheral wbc rises progressively during pregnancypregnancy

1st ∆ – mean 9500/mm3 (3000-15,000)1st ∆ – mean 9500/mm3 (3000-15,000) 2nd and 3rd ∆ – mean 10,500 (6000-16,000)2nd and 3rd ∆ – mean 10,500 (6000-16,000) Labor – may rise to 20-30,000Labor – may rise to 20-30,000

Rise is due to increase in pmns Rise is due to increase in pmns (demargination)(demargination)

PLATELETSPLATELETS Platelets experience a progressive decline Platelets experience a progressive decline

but should remain within normal range but should remain within normal range Likely due to increased destructionLikely due to increased destruction

HematologyHematology COAGULATION FACTORSCOAGULATION FACTORS

Increased levelsIncreased levels Fibrinogen (Factor I)Fibrinogen (Factor I) Factors VII through XFactors VII through X

No change in prothrombin (Factor No change in prothrombin (Factor II), Factors V and XIIII), Factors V and XII

Decline in platelet count, Factors Decline in platelet count, Factors XI and XIIIXI and XIII Bleeding time and clotting time are Bleeding time and clotting time are

unchanged in normal pregnancyunchanged in normal pregnancy

Cardiovascular – Cardiac Cardiovascular – Cardiac outputoutput

Maternal cardiac output increases Maternal cardiac output increases about 30-50% during pregnancy (mean about 30-50% during pregnancy (mean 33%) 33%) pregnancy maximum of 6 L/minpregnancy maximum of 6 L/min CO remains maximal until deliveryCO remains maximal until delivery Earliest rise in CO is due to increase in SV Earliest rise in CO is due to increase in SV As pregnancy progressesAs pregnancy progresses

Gradual increase in mat HR (15-20 bpm rise)Gradual increase in mat HR (15-20 bpm rise) SV declines to near non-pregnant levelsSV declines to near non-pregnant levels increase HR is what maintains the elevated COincrease HR is what maintains the elevated CO


CO is position dependentCO is position dependent Lower when supine Lower when supine

IVC compression by the uterus reduces venous IVC compression by the uterus reduces venous return to the heartreturn to the heart

At 38-40 weeks, there is a 25-30% fall in At 38-40 weeks, there is a 25-30% fall in CO when turning from the side to the back CO when turning from the side to the back

Fall in CO is compensated by a rise in Fall in CO is compensated by a rise in peripheral vascular resistance peripheral vascular resistance

supine hypotensive syndrome (1-10% patients)supine hypotensive syndrome (1-10% patients)


Distribution of CODistribution of CO First trimester and non-pregnant stateFirst trimester and non-pregnant state

Uterus receives 2-3%Uterus receives 2-3% By termBy term

Uterus receives 17%Uterus receives 17% Breasts 2%Breasts 2%

Reduction of the fraction of CO going to Reduction of the fraction of CO going to the splanchnic bed and skeletal musclethe splanchnic bed and skeletal muscle

CO to the kidneys, skin, brain and CO to the kidneys, skin, brain and coronary arteries does not changecoronary arteries does not change

Cardiovascular – Arterial Cardiovascular – Arterial BPBP

BP varies with positionBP varies with position

Peripheral vascular resistance falls during Peripheral vascular resistance falls during pregnancypregnancy

Progesterone’s smooth muscle relaxing effectProgesterone’s smooth muscle relaxing effect ?heat production by the fetus ?heat production by the fetus vasodilatation vasodilatation

The reduction in PVR may lead to a The reduction in PVR may lead to a progressive fall in systemic arterial bp progressive fall in systemic arterial bp during the first 24 weeks of pregnancyduring the first 24 weeks of pregnancy

Gradual rise after 24 weeksGradual rise after 24 weeks non-pregnant non-pregnant levels by termlevels by term

Cardiovascular – Venous Cardiovascular – Venous systemsystem

Venous compliance increases during Venous compliance increases during pregnancypregnancy decrease in flow velocity and stasisdecrease in flow velocity and stasis ?progesterone effects on smooth muscle?progesterone effects on smooth muscle Forearm venous pressure increases by Forearm venous pressure increases by

40-50%40-50% Calf venous pressures are always Calf venous pressures are always

higherhigher due to the enlarging uterusdue to the enlarging uterus

Cardiovascular - LV Cardiovascular - LV functionfunction

Left ventricular dimensions and Left ventricular dimensions and volume increase during pregnancyvolume increase during pregnancy most parameters of LVF are the same most parameters of LVF are the same

as in the non-pregnant stateas in the non-pregnant state Ejection fraction, rate of internal diameter Ejection fraction, rate of internal diameter

shortening, percentage of fractional shortening, percentage of fractional shortening, and ventricular wall thicknessshortening, and ventricular wall thickness

Bottom line: preservation of Bottom line: preservation of myocardial functionmyocardial function

Signs and Symptoms of Normal Signs and Symptoms of Normal PregnancyPregnancy

SymptomsSymptoms reduced exercise tolerancereduced exercise tolerance dyspnea dyspnea

SignsSigns peripheral edema peripheral edema distended neck veinsdistended neck veins point of maximal impulse displaced to point of maximal impulse displaced to

the left the left


AuscultationAuscultation increased splitting of the first and increased splitting of the first and

second heart soundsecond heart sound S3 gallopS3 gallop SEM along the left sternal border SEM along the left sternal border Continuous murmursContinuous murmurs


CXRCXR straightening of left heart borderstraightening of left heart border heart position more horizontal – may heart position more horizontal – may

appear as cardiomegaly on cxrappear as cardiomegaly on cxr increased vascular markings in lungsincreased vascular markings in lungs

ECG ECG left axis deviationleft axis deviation non-specific ST-T wave changesnon-specific ST-T wave changes

Cardiovascular - LaborCardiovascular - Labor

First stage of labor: 12-31% rise on CO First stage of labor: 12-31% rise on CO due to an increase in SVdue to an increase in SV

Second stage of labor: 34% increase in Second stage of labor: 34% increase in COCO Not only pain-relatedNot only pain-related UCs result in the transfer of 300-500 cc of UCs result in the transfer of 300-500 cc of

blood from the uterus to the general blood from the uterus to the general circulationcirculation

Enhanced venous return to the heartEnhanced venous return to the heart Increase in CO by 10-15%Increase in CO by 10-15%

Cardiovascular - Cardiovascular - PostpartumPostpartum

Immediate pp period: 10-20% rise in Immediate pp period: 10-20% rise in COCO release of obstruction of venous return release of obstruction of venous return extracellular fluid mobilizationextracellular fluid mobilization

Rise in CO associated with reflex Rise in CO associated with reflex bradycardiabradycardia SV increases SV increases this may persist for one this may persist for one

to two weeks after deliveryto two weeks after delivery

QUESTIONQUESTION

During which of the following During which of the following states is the blood pressure lowest?states is the blood pressure lowest?

a)a) First trimesterFirst trimester

b)b) Second trimesterSecond trimester

c)c) Third trimesterThird trimester

d)d) Non pregnantNon pregnant

QUESTIONQUESTION

Increased cardiac output Increased cardiac output immediately postpartum is due to:immediately postpartum is due to:

a)a) Increased HRIncreased HR

b)b) Release of obstruction of venous Release of obstruction of venous returnreturn

c)c) Reduced mobilization of extracellular Reduced mobilization of extracellular fluidfluid

d)d) Reduced stroke volumeReduced stroke volume

Respiratory systemRespiratory system

UPPER RESPIRATORY TRACTUPPER RESPIRATORY TRACT Hyperemic mucosa of nasopharynx Hyperemic mucosa of nasopharynx

Estrogen-mediatedEstrogen-mediated nasal stuffiness and epistaxisnasal stuffiness and epistaxis

Polyposis of nose and sinuses may occur and regress after Polyposis of nose and sinuses may occur and regress after deliverydelivery

““chronic cold” chronic cold”

MECHANICAL CHANGESMECHANICAL CHANGES Configuration of thoracic cage changes early in pregnancyConfiguration of thoracic cage changes early in pregnancy

Increase in subcostal angle, transverse diameter and Increase in subcostal angle, transverse diameter and circumference of chest circumference of chest

With advancing gestation, the level of diaphragm is pushed With advancing gestation, the level of diaphragm is pushed upup

Changes in pulmonary Changes in pulmonary function tests during function tests during

pregnancypregnancy

Serial measurements of lung volume compartments during pregnancy. Functional residual capacity decreases approximately 20 percent during the latter half of pregnancy, due to a decrease in both expiratory reserve volume and residual volume. Redrawn from Prowse, CM, Gaensler, EA, Anesthesiology 1965; 26:381.

Serial measurements of lung volume compartments during pregnancy. Functional residual capacity decreases approximately 20 percent during the latter half of pregnancy, due to a decrease in both expiratory reserve volume and residual volume. Redrawn from Prowse, CM, Gaensler, EA, Anesthesiology 1965; 26:381.


LUNG VOLUME AND PULMONARY LUNG VOLUME AND PULMONARY FUNCTIONFUNCTION 30-40% increase in tidal volume 30-40% increase in tidal volume

(Amount of air I and E with each (Amount of air I and E with each breath)breath) 30-40% increase in minute ventilation 30-40% increase in minute ventilation

(likely P4 mediated)(likely P4 mediated) ERV falls by 20%ERV falls by 20% Vital capacity and inspiratory reserve Vital capacity and inspiratory reserve

volume remain unchangedvolume remain unchanged


LUNG VOLUME AND PULMONARY LUNG VOLUME AND PULMONARY FUNCTION FUNCTION Respiratory rate is unchangedRespiratory rate is unchanged Due to elevation of the diaphragmDue to elevation of the diaphragm

Total lung volume decreases (diaphragm) by Total lung volume decreases (diaphragm) by 5%5%

Residual volume decreases (RV) by 20%Residual volume decreases (RV) by 20% FRC is reduced 20%FRC is reduced 20%

No change in FEV1 or the ratio of FEV1 No change in FEV1 or the ratio of FEV1 to forced vital capacityto forced vital capacity


GAS EXCHANGEGAS EXCHANGE Minute ventilation rises 30-40% by late Minute ventilation rises 30-40% by late

pregnancypregnancy O2 consumption increases only 15-29%O2 consumption increases only 15-29%

Results in higher PAO2 (alveolar) and PaO2 (arterial) Results in higher PAO2 (alveolar) and PaO2 (arterial) Normal PaO2: 104-108 mmHgNormal PaO2: 104-108 mmHg

Fall in PACO2 and PaCO2 levelsFall in PACO2 and PaCO2 levels Normal PaCO2 level: 27-32 mmHgNormal PaCO2 level: 27-32 mmHg

Increases gradient of CO2 facilitating transfer from Increases gradient of CO2 facilitating transfer from fetus to motherfetus to mother

Arterial pH remains unchanged Arterial pH remains unchanged Increased bicarbonate excretion via kidneysIncreased bicarbonate excretion via kidneys


DYSPNEA OF PREGNANCYDYSPNEA OF PREGNANCY Common complaint Common complaint

60-70% of patients60-70% of patients late first or early second trimesterlate first or early second trimester

Likely due to various factorsLikely due to various factors reduced PaCO2 levelsreduced PaCO2 levels awareness of increased tidal volume of awareness of increased tidal volume of

pregnancypregnancy

QUESTIONQUESTION

Which of the following is increased Which of the following is increased in pregnancy?in pregnancy?

a)a) FRCFRC

b)b) ERVERV

c)c) RVRV

d)d) TVTV

Renal systemRenal system

ANATOMYANATOMY Kidney enlargementKidney enlargement

increased renal vascular and interstitial volume, R>Lincreased renal vascular and interstitial volume, R>L Ureteral and renal pelvis dilatation by 8 weeksUreteral and renal pelvis dilatation by 8 weeks

Right > left Right > left mechanical compression by uterus and ovarian venous mechanical compression by uterus and ovarian venous

plexus plexus smooth muscle relaxation by progesteronesmooth muscle relaxation by progesterone

ImplicationsImplications Increased incidence of pyelonephritisIncreased incidence of pyelonephritis difficulty in interpreting radiographsdifficulty in interpreting radiographs interference with studiesinterference with studies


RENAL HEMODYNAMICSRENAL HEMODYNAMICS Effective renal plasma flow (ERPF) and Effective renal plasma flow (ERPF) and

GFR increaseGFR increase Filtration fraction fallsFiltration fraction falls

Returns to normal by late third ΔReturns to normal by late third Δ

Endogenous creatinine clearance Endogenous creatinine clearance increases increases Begins by 5 weeks Begins by 5 weeks


METABOLITESMETABOLITES increased GFR increased GFR decline in serum urea and decline in serum urea and

creatininecreatinine BUN – 8-9 mg/dl by end 1BUN – 8-9 mg/dl by end 1stst Δ Δ Decline in serum creatinine Decline in serum creatinine

0.7 mg/dl by end 10.7 mg/dl by end 1stst Δ Δ 0.5-0.6 mg/dl by term0.5-0.6 mg/dl by term

Early decline in serum uric acid levelsEarly decline in serum uric acid levels nadir at 24 weeksnadir at 24 weeks same as nonpregnant level at end of pregnancy due same as nonpregnant level at end of pregnancy due

to increased reabsorption of urateto increased reabsorption of urate


SALT AND WATER METABOLISMSALT AND WATER METABOLISM Plasma osmolality begins to decline by 2 Plasma osmolality begins to decline by 2

weeks after conceptionweeks after conception reduction in serum sodium and other anionsreduction in serum sodium and other anions

Sodium loss during pregnancySodium loss during pregnancy 50% rise in GFR50% rise in GFR Progesterone: natriuresisProgesterone: natriuresis

Renal tubular reabsorption of Na+ increases Renal tubular reabsorption of Na+ increases (aldosterone, estrogen and (aldosterone, estrogen and deoxycorticosterone)deoxycorticosterone)

Sodium homeostasisSodium homeostasis


NUTRIENT EXCRETIONNUTRIENT EXCRETION Increase in glucose excretionIncrease in glucose excretion

1-10 g glucose excretion per day 1-10 g glucose excretion per day Due to 50% increase in GFR Due to 50% increase in GFR

implicationsimplications inability to use urine glucose inability to use urine glucose susceptibility of pregnant women to UTIsusceptibility of pregnant women to UTI

Increase in amino acid excretion during Increase in amino acid excretion during gestationgestation

no increased protein loss (100-300 mg/24 hr)no increased protein loss (100-300 mg/24 hr) Increased urinary loss of folate and vitamin Increased urinary loss of folate and vitamin

B12B12

QUESTIONQUESTION

All of the following are increased in All of the following are increased in pregnancy except:pregnancy except:

a)a) Renal plasma flowRenal plasma flow

b)b) GFRGFR

c)c) Serum creatinineSerum creatinine

d)d) Tubular sodium resorptionTubular sodium resorption

Gastrointestinal - Gastrointestinal - AppetiteAppetite

Increase early 1st ΔIncrease early 1st Δ

Increase intake 200 kcal by end 1st Δ Increase intake 200 kcal by end 1st Δ RDA: 300 kcal/day during pregnancyRDA: 300 kcal/day during pregnancy

Sense of taste may be bluntedSense of taste may be blunted

Pica Pica check for poor weight gain and refractory check for poor weight gain and refractory

anemiaanemia South - clay or starch (laundry or cornstarch)South - clay or starch (laundry or cornstarch) UK – coalUK – coal Also soap, toothpaste and ice picaAlso soap, toothpaste and ice pica

Gastrointestinal - MouthGastrointestinal - Mouth Unchanged pH or production of salivaUnchanged pH or production of saliva

Saliva production is unalteredSaliva production is unaltered Ptyalism – usually in women with HEGPtyalism – usually in women with HEG

due to inability to swallowdue to inability to swallow Can lose up to 1-2 L of saliva per dayCan lose up to 1-2 L of saliva per day Decreasing starchy foods might helpDecreasing starchy foods might help

Gums – edematous and softGums – edematous and soft May bleed after brushingMay bleed after brushing

Epulis gravidarumEpulis gravidarum regress 1-2 mos after deliveryregress 1-2 mos after delivery excise if persistent or excessive bleeding excise if persistent or excessive bleeding

Gastrointestinal - Gastrointestinal - StomachStomach

Decreased tone and motility Decreased tone and motility progesteroneprogesterone possibly due to decreased levels of motilitypossibly due to decreased levels of motility

Conflicting info about delayed gastric emptyingConflicting info about delayed gastric emptying Reduced tone of the gastroesophageal junction Reduced tone of the gastroesophageal junction

sphinctersphincter Increased intraabdominal pressure leads to acid Increased intraabdominal pressure leads to acid

refluxreflux Lower incidence of PUD Lower incidence of PUD

may be due to decreased gastric acid may be due to decreased gastric acid secretion delayed emptying, increase in secretion delayed emptying, increase in gastric mucus, and protection of mucosa by gastric mucus, and protection of mucosa by prostaglandinsprostaglandins

Gastrointestinal - Small Gastrointestinal - Small bowelbowel

Reduced motility of small Reduced motility of small bowelbowelincreased transit time in the increased transit time in the third trimester and postpartumthird trimester and postpartum

Enhanced iron absorption Enhanced iron absorption as a response to increased iron as a response to increased iron needsneeds

Gastrointestinal - ColonGastrointestinal - Colon Constipation Constipation

Mechanical obstruction by the uterusMechanical obstruction by the uterus Reduced motility (p4)Reduced motility (p4) Increased water absorptionIncreased water absorption

Portal venous pressure is increasedPortal venous pressure is increased Dilation of gastroesophageal vesselsDilation of gastroesophageal vessels

issue in those with preexisting esophageal varicesissue in those with preexisting esophageal varices Dilation of hemorrhoidal veinsDilation of hemorrhoidal veins

hemorrhoidshemorrhoids

Gastrointestinal - Gastrointestinal - GallbladderGallbladder

Fasting and residual volumes double Fasting and residual volumes double in 2nd and 3rd Δin 2nd and 3rd Δ Slower rate of emptyingSlower rate of emptying

Biliary cholesterol saturation Biliary cholesterol saturation increases and chenodeoxycholic acid increases and chenodeoxycholic acid decreasesdecreases increased risk gallstone formationincreased risk gallstone formation

Gastrointestinal - LiverGastrointestinal - Liver Liver does not enlargeLiver does not enlarge Hepatic blood flow remains unchangedHepatic blood flow remains unchanged

CO to the liver decreases by ~35%CO to the liver decreases by ~35% Spider angiomata and palmar erythema Spider angiomata and palmar erythema

elevated estrogen levelselevated estrogen levels Lab dataLab data

Drop in serum albuminDrop in serum albumin Rise in serum alkaline phosphatase Rise in serum alkaline phosphatase

placental production and some hepatic productionplacental production and some hepatic production Rise in serum cholesterol, fibrinogen, ceruloplasmin, Rise in serum cholesterol, fibrinogen, ceruloplasmin,

binding proteins for corticosteroids, sex steroids, binding proteins for corticosteroids, sex steroids, thyroid hormones, and vitamin D thyroid hormones, and vitamin D

No change in serum bilirubin, AST, ALT, protime and 5’ No change in serum bilirubin, AST, ALT, protime and 5’ nucleotidasenucleotidase

Rise in GGT is controversialRise in GGT is controversial

Gastrointestinal systemGastrointestinal system NAUSEA AND VOMITINGNAUSEA AND VOMITING

Morning sickness complicates 70% of pregnanciesMorning sickness complicates 70% of pregnancies Onset 4-8 weeks up to 14-16 weeksOnset 4-8 weeks up to 14-16 weeks Cause? Cause?

Relaxation of smooth muscle of stomach, elevated levels Relaxation of smooth muscle of stomach, elevated levels of steroids and hCGof steroids and hCG

Rx – supportive: reassurance, support, and avoiding Rx – supportive: reassurance, support, and avoiding triggers…triggers…

HEGHEG weight loss, ketonemia, electrolyte imbalance and weight loss, ketonemia, electrolyte imbalance and

dehydrationdehydration possible renal or hepatic damagepossible renal or hepatic damage IVF, antiemeticsIVF, antiemetics

NPONPO continue IV continue IV

ConclusionConclusion

Understanding maternal physiology is Understanding maternal physiology is crucial in understanding the changes and crucial in understanding the changes and clinical scenarios associated in clinical scenarios associated in pregnancypregnancy

This knowledge will help us distinguish This knowledge will help us distinguish the physiologic and pathologic processes the physiologic and pathologic processes during pregnancyduring pregnancy

This knowledge will also improve This knowledge will also improve patient’s education about their patient’s education about their pregnancypregnancy

Endocrine - ThyroidEndocrine - Thyroid The normal pregnant woman is euthyroid The normal pregnant woman is euthyroid Changes in thyroid morphology and lab indicesChanges in thyroid morphology and lab indices

Estrogen-induced increase in TBGEstrogen-induced increase in TBG Decreased circulating extrathyroidal iodide Decreased circulating extrathyroidal iodide Thyroid enlargement usually not detected by examThyroid enlargement usually not detected by exam Normal thyroidal uptake of iodide Normal thyroidal uptake of iodide

Serum TSH decreases early in gestation Serum TSH decreases early in gestation rises to pre-pregnancy levels by end of first Δrises to pre-pregnancy levels by end of first Δ

T4 increases early in gestationT4 increases early in gestation role of hCG stimulating the thyroidrole of hCG stimulating the thyroid

Rise in TBG leads to rise in total T4 and total T3Rise in TBG leads to rise in total T4 and total T3 active hormones free T4 and free T3 are unchangedactive hormones free T4 and free T3 are unchanged

Free T4 is the most reliable method of evaluating thyroid Free T4 is the most reliable method of evaluating thyroid function in pregnancyfunction in pregnancy

Endocrine - Adrenal Endocrine - Adrenal glandsglands

Expansion of the zona fasciculataExpansion of the zona fasciculata site of glucocorticoid productionsite of glucocorticoid production

Plasma corticosteroid-binding globulin Plasma corticosteroid-binding globulin (CBG) rises(CBG) rises due to enhanced liver synthesis due to enhanced liver synthesis

Free plasma cortisol rises Free plasma cortisol rises increased production and delayed clearanceincreased production and delayed clearance

Plasma DOC (deoxycorticosterone) risesPlasma DOC (deoxycorticosterone) rises fetoplacental unitfetoplacental unit

DHEAS (dehydroepiandrosterone) decreases DHEAS (dehydroepiandrosterone) decreases Testosterone is slightly elevated Testosterone is slightly elevated

Increased SHBG and androstenedioneIncreased SHBG and androstenedione

Endocrine - PancreasEndocrine - Pancreas Hypertrophy and hyperplasia of the B cells Hypertrophy and hyperplasia of the B cells Fasting associated with accelerated starvationFasting associated with accelerated starvation

maternal hypoglycemia, hypoinsulinemia and maternal hypoglycemia, hypoinsulinemia and hyperketonemia hyperketonemia

due to diffusion of glucose by the fetoplacental unitdue to diffusion of glucose by the fetoplacental unit Feeding responseFeeding response

hyperglycemia, hyperinsulinemia, hyperglycemia, hyperinsulinemia, hypertriglyceridemia and reduced tissue sensitivity to hypertriglyceridemia and reduced tissue sensitivity to insulininsulin

glucose response greater during pregnancy glucose response greater during pregnancy peripheral resistance to insulin: peripheral resistance to insulin: diabetogenic effect of diabetogenic effect of

pregnancypregnancy.. hPL and cortisol mediated hPL and cortisol mediated greater insulin resistance as the pregnancy greater insulin resistance as the pregnancy

advancesadvances

Endocrine - PancreasEndocrine - Pancreas Fetus primarily depends on glucoseFetus primarily depends on glucose

Facilitated diffusion Facilitated diffusion carrier-mediated but not energy carrier-mediated but not energy

dependent processdependent process

Active transport of amino acids to Active transport of amino acids to the fetusthe fetus

Ketones diffuse freely across the Ketones diffuse freely across the placentaplacenta

Endocrine - PituitaryEndocrine - Pituitary

The pituitary gland enlarges in The pituitary gland enlarges in pregnancypregnancy

proliferation of chromophobe cells proliferation of chromophobe cells on the anterior pituitaryon the anterior pituitary

stalk remains midlinestalk remains midline

SkinSkin Spider angiomata (face, upper chest, Spider angiomata (face, upper chest,

and arm) and palmar erythemaand arm) and palmar erythema elevated estrogen levels elevated estrogen levels both regress after deliveryboth regress after delivery

Striae gravidarumStriae gravidarum

Increased eccrine sweating and Increased eccrine sweating and sebum excretionsebum excretion

SkinSkin Hyperpigmentation Hyperpigmentation Melasma: “mask of pregnancy”Melasma: “mask of pregnancy”

elevated e2 and p4elevated e2 and p4 Nevi may darken, enlarge or show increased Nevi may darken, enlarge or show increased

activityactivity rapidly changing nevi should be excisedrapidly changing nevi should be excised

Hairs in telogen phase decrease in late Hairs in telogen phase decrease in late pregnancypregnancy increases after delivery increases after delivery hair loss 2-4 mos pp hair loss 2-4 mos pp re-growth in 6-12 mosre-growth in 6-12 mos

Masculinization of the skin rarely occurs Masculinization of the skin rarely occurs evaluate for possible luteomas of pregnancy (which evaluate for possible luteomas of pregnancy (which

regress after delivery)regress after delivery)

BreastsBreasts Early changeEarly change

tenderness, tingling and heavinesstenderness, tingling and heaviness vascular engorgement leads to enlargementvascular engorgement leads to enlargement

Ductal growth due to e2Ductal growth due to e2 Alveolar hypertrophy due to p4Alveolar hypertrophy due to p4

Enlargement and pigmentation of areolae Enlargement and pigmentation of areolae Colostrum may be expressed later in Colostrum may be expressed later in

pregnancypregnancy Milk productionMilk production

E2, p4, prolactin, hPL, cortisol and insulinE2, p4, prolactin, hPL, cortisol and insulin Lactation likely due to drop in estrogen and Lactation likely due to drop in estrogen and

progesterone after deliveryprogesterone after delivery

SkeletonSkeleton Lordosis Lordosis

keep center of gravity over the legskeep center of gravity over the legs back pain…back pain…

Relaxin Relaxin relaxation of the pubic symphysis and relaxation of the pubic symphysis and

sacroiliac jointssacroiliac joints facilitates vaginal delivery but may lead to facilitates vaginal delivery but may lead to

discomfortdiscomfort ImplicationsImplications

unsteadiness of gait and trauma from unsteadiness of gait and trauma from fallsfalls

SkeletonSkeleton Total serum calcium declines throughout Total serum calcium declines throughout

pregnancy until 34-36 weeks pregnancy until 34-36 weeks due to the fall in serum albumindue to the fall in serum albumin

Serum ionized calcium is constant and Serum ionized calcium is constant and unchangedunchanged ““Physiologic hyperparathyroidism”Physiologic hyperparathyroidism”

increased gut absorptionincreased gut absorption decreased renal lossesdecreased renal losses no bone loss seen in bone density studiesno bone loss seen in bone density studies

preservation due to calcitonin?preservation due to calcitonin? Rate of bone turnover and remodeling Rate of bone turnover and remodeling

increases throughout pregnancyincreases throughout pregnancy twice as great at termtwice as great at term

EyeEye

Increased thickness of Increased thickness of cornea due to fluid retention cornea due to fluid retention (contact lens intolerance)(contact lens intolerance)

Decreased intraocular Decreased intraocular pressurepressure

maternal physiology sindhu srinivas, md, msce division of maternal fetal medicine

Documents

normal pregnancy slide

increase hr

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pregnancy peripheral

lmin pregnancy maximum