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UTERUS

Change in size, weight, and capacity

Transformed into a muscular sac

Total volume: ave. !iters

"terine weight may reach appro#. $$%%g

"terine enlargement involves stretching and

mar&ed hypertrophy of muscles

"terine hypertrophy is pro'a'ly stimulated 'yestrogen and progesterone after $(w&s

increase in size is related predominantly to

pressure e#erted 'y the e#panding products

of conception

"terine musculature in pregnancy is arranged

as:$. )uter hoodli&e layer arching over the

fundus and e#tending into the various

ligaments(. Middle layer composed of dense networ&

of muscle *'er perforated in all directions.

+. nternal layer with sphincter-li&e *'ersaround the fallopian tu'e ori*ces and

internal os of the cervi#

Braxton-Hicks contraction noted during

early pregnancy 'ecoming more fre/uent with

pregnancy approaches termo "npredicta'le, sporadic and non rhythmic

contractions with pressure varying from -

(mm0g

Uteroplacental Blood Flow

o Placental perfusion is dependent upon

total uterine 1ow

o "teroplacental 'lood 1ow increasesprogressively ranging from 2%-3%ml4min

near termo "terine contractions decreases uterine5s

'lood 1ow in proportion to the intensity of

the contraction

UTERUS

6egulation of "teroplacental 7lood 8low

Progressive increase in uteroplacental 'lood

1ow occurs principally 'y means of

vasodilation:o 8etal placental 'lood 1ow in increase 'y

continuing growth of placental vessels.o 9asodilation is at least in part the

conse/uence of estrogen stimulation and

in part due to progesteroneo igni*cant decrease in uterine 'lood 1ow

and placental perfusion have 'een show

following nicotine and catecholamine

infusion.

o ;ormal pregnancy is characterized 'y

vascular refractoriness to the pressure

e? musculature undergoes little hypertrophyduring pregnancy

9A=;A A;D P>6;>"M? Chadwic& sign- due to increased vascularity andhypermedia of the vagina? vaginal wall changes include:

? increased thic&ness of mucosa? loosening of connective tissue

? hypertrophy of smooth muscle cells? hypertrophy of papillae of vaginal

mucosa

B;? increased cutaneous 'lood 1ow serves todissipate e#cess heat due to increasedmeta'olismA'dominal wall

? striae gravidarum or stretch mar&s? diastasis recti

Pigmentation

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? !inea ;egra - mar&ed pigmentation ofthe midline of the a'dominal s&in

? chloasma or melasma gravidarum -mas& of pregnancy

? due to elevation of melanocytestimulating hormones9ascular changes

? angiomas or vascular spiders? palmar erythema

76>AT? early wee&s of pregnancy - 'reast tendernessand tingling? increase in size and appearance of delicateveins 'eneath the s&in gigantomastia- needssurgery? larger, deeply pigmented and more erectilenipples? colostrum - thic& yellowish 1uid may 'ee#pressed from the nipples

M>TA7)!C C0A;=>

Eeight gain? attri'uta'le to the uterus and its contents,'reasts, increase in 'lood volume and e#travascular >C8? increase on cellular water and deposition ofnew fat and protein? averages a'out $(. &h or (@. l's? ( l's for o'ese? + l's for underweight

Eater meta'olism? increased water retention occurs normally- duein part to fall in plasma osmolality induced 'yresetting of osmotic threshold for thirst andvasopressin secretion? minimum amount of e#tra water duringpregnancy is a'out 3.!

? +. ! - fetus, placenta, amniotic 1uid? + ! - maternal 'lood volume, size of

uterus, 'reast? edema of an&les and legs - due to increasedvenous pressure? maternal 'ody water rather than fat contri'utesto infant 'irthweight

protein meta'olism? a'out half of the total pregnancy increase isdue to protein rather than fat and car'ohydrate? nitrogen 'alance progressive increases withgestation

Car'ohydrate meta'olism? normal pregnancy is characterized 'y:

? mild fasting hypogly? postprandial hyperglycemia? hyperinsulinemia

? pregnancy induced state of peripheralresistance to insulin, the purpose is to ensure

sustained supply of glucose to the fetus - 2 to@%F lower sensitivity? possi'le mechanisms of insulin resistance:

$. Progesterone and estrogen maymediate resistance

(. ncreased concentration of circulating88A may aid tissue resistance to insulin? the pregnant woman changes rapidly from apostprandial state characterized 'y elevated and

sustained glucose levels to a fasting statecharacterized 'y decreased plasma glucose andamino acids - switch in fuel from glucose to lipids- referred as ACC>!>6AT>D TA69AT);? central fat

8at meta'olism? lipids, lipoproteins and apoliproteins in plasmaincreases apprecia'ly during pregnancy? fat storage and deposition occurs mostlycentrally? fat can 'e energy source protecting mother

fetus during prolonged starvation and hardphysical e#ertion? maternal hyperlipidemia occurs during latepregnancy

>lectrolyte and mineral meta'olism? nearly $%%% m>/ of sodium and +%% m>/ ofpotassium is retained during normal pregnancy? total serum calcium and magnesium declineduring pregnancy? serum phosphate is within nonpregnant range? considera'le increase in iron re/uirement

0g' (nd trimester must 'e G$%. mg4d!+rd trimester must 'e G$$ mg4d!

7lood volume? maternal 'lood volume increases 2%-2F a'ovethe nonpregnant level at or very near term? functions of pregnancy induced hypervolemia:

? meet the demands of enlarged uteruswith its greatly hypertrophied vascular system

? protect mother and features from thedeleterious e

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? iron re/uirement during (nd half of pregnancyis 3-@ mg4d!

mmunological4 leu&ocyte functions? suprresssion of a variety of humoral and cellmediated immunological functions in order toaccommodate the fetus? pea& levels of gA and = are higher in thecervical mucus enhancing local 6T immunity

? leu&ocyte count varies considera'ly duringpregnancy

Coagulation? coagulation cascade is in an activated state? increase in all clotting factors e#cept H and H? clotting times however does not di/uili'rium

Physiologic dyspnea may 'e noted

May 'e due to increased Total 9olume thatlowers the 'lood PC)( level slightly

Progesterone and estrogen cause increasedrespiratory epulis of pregnancy focal highly vascular

swelling of gum 0emorrhoids caused 'y constipation and

elevated pressure of the veins 'elow theenlarged uterus

!iver

Diameter of portal vein and its 'lood 1ow is

increased

Alteration of la'oratory test results li&e =PT,

=)T, 'iliru'in test are decreased whileal&aline phosphatase actively dou'les

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=all7ladder

6educed contracta'ility of the gall'ladder

smooth muscle

tasis and increased choledterol saturation

may increase prevalence of cholesterol stonesamong multiparous women

Pruritus gravidadum due to retained 'ile

salts

Propensity for pregnancy to cause

intrahepatic cholestasis

>;D)C6;> JT>MPituitary =land

>nlarges a'out $+F

Maternal pituitary gland is not essential for

maintenance of pregnancy

=rowth hormone principal source is the

placenta 'y $@thwee&

Prolactin increases mar&edly during

pregnancy

Thyroid =land+ modi*cations in the regulation of Thyroid0ormone:

$. ncreased thro#ine 'inding glo'ulin due toestrogen

(. >#cess thyroidal stimulatory factors fromplacenta

+. Decreased availa'ility of iodide for maternalthyroid

"ndergoes moderate enlargement due to

glandular hyperplasia and increasedvascularity

Comple# alteration in the thyroid regulation

do not appear to alter maternal thyroid statusas measure 'y meta'olic studies

0C= has intrinsic throdotropin activity

resulting in thyroid stimulation andthyrotropin level decrease

7M6 increases to as much as (F - most of

increase in )( consumption due to fetalmeta'olic activity

Prolactin

Mar&edly increased during pregnancy $%#

greater

Plasma concentration decreses following

delivery

Principal function of prolactin is to ensure

lactation

Prolactin is present in the amniotic 1uid in

high concentration and is pro'a'ly importantto prevent fetal dehydration

Parathyroid =land

tudies have shown that all mar&ers of 'oneturnover increased during pregnancy and thatcalcium needed for fetal growth and lactationmay 'e drawn at least in part from maternals&eleton

PT0 initially decreases during $sttrimester

then progressively increases duringpregnancy 'ecause of lower calciumconcentration

Physiological hyperparathyroidism in

pregnancy ensures an ade/uate supply ofcalcium to the fetus

Calcitonin level are also increased to protect

maternal s&eleton calci*cation

Adrenal =land

"ndergoes little if any morphological change

erum concentration of serum cortisol is

increased 'ut much of it is 'ound 'ytranscortin

ncreased secretion of aldosterone was noted

in as early as $ wee&s of pregnancy reachinga'out $mg4day 'y the +rdtrimester ofpregnancy

ncreased aldosterone secretion in normal

pregnancy a!>TA! JT>M

Progressive lordosis is a characteristic feature

7ones and ligaments undergo remar&a'le

adaptation during pregnancy