Transcript Physiological Changes in the Pregnancy

Physiological changes in :
 Blood
 CVS
 Respiratory system
 Renal system
 Endocrine
 Metabolism
 Skin
 Reproductive organs
Physiological changes in the
pregnancy are aimed to
↙
To maximize nutrition
and oxygen to
developing fetus
↘
Help maternal
system adjust to the
extra stress
Increase to max
40% above non
pregnant level
↘
↙
↑↑Plasma volume
↑Erythrocytes mass
Factors contributing to fluid retention
•Sodium retention.
• Resetting of osmostat.
• ↓ Thirst threshold.
• ↓ Plasma oncotic pressure.
Consequence of blood volume expanding
↓
↓
↓
↑ Stoke volume
↑ Renal blood
flow
↑Placental blood
flow
↑↑Plasma volume>↑Erythrocyte
volume
(Heamodilution)
↓Heamoglobuline
↓heamatocrite
↓ RBC count
↓ Albumine concntration
1.
↓RBC count
2.
↑WBC
3.
Platelets count unchanged , reactivity
increase, their survival is reduced in
pregnancy.
thrombotic
↓
All clotting factors
increased
antithrombotic
↓
fibrinolytic
↓
1-Plasminogen levels
are increased during
pregnancy
2- plasma D-dimer
concentration
increases progressively
-Antithrombin III levels remain
unchanged
- protein S activity decreases
- activated protein C
resistance increase.
antifibrinolytic
↓
-α2-antiplasmin
decreased
-plsminogen activator
inhibitor increased

Iron requirement during pregnancy is increased

pregnancy without iron supplementation leads to
depletion of iron stores.

plasma folate concentration decreased due to
increase renal clearance of folat

red cell folate concentrations do not decrease
• ↑ Heart rate (10–20 per cent).
• ↑ Stroke volume (10 per cent).
• ↑ Cardiac output (30–50 per cent).
• ↓ Peripheral resistance (35 per cent)
• ↓ Mean arterial pressure (10 per cent).
• ↓ Pulse pressure.

1-The first heart sound is loud and sometimes split

2- a third heart sound is audible in 84 per cent of pregnant
women by 20 weeks gestation.

3- An ejection systolic murmur can be heard in 96 per cent
of apparently normal pregnant women.

4-diastolic murmur occurs transiently in only 20 percent of
pregnant women

5- 10 per cent develop continuous murmurs due to increased
mammary blood flow.

the heart is displaced to the left and upward and
rotated somewhat on its long axis du to progressive
elevation of diaphragm ,as result:
1.
the apex is moved somewhat laterally from its usual
position
2.
causing a larger cardiac silhouette on chest
radiograph .
3.
Normal pregnancy induces slight left-axis deviation
Respiratory system

2- the diaphragm is elevated 4 cm by the
enlarging uterus.

3-the lower ribcage circumference
expands by 5 cm.

4- increasing the ribcage subcostal angle.

Ventilation
•↑ Minute ventilation.
• ↑ Tidal volume.
•↓ERV
•↓RV
•↓FRC
•FEV1&PEV (unchang)
hyperventilation
↓
↑↑Carbonic anhydrase
↓
↓↓CO2+H2O↔H2CO3↔HCO3
↓
renal excretion
hyperventilation
↓
↑ po2
←
+H
↓
2,3-DPG
↓
right shift of oxyheamoglobulin dissociation
curve
• ↓ pCO2(30-50)%.
• ↑ pO2.
• pH alters little.
• ↑ Bicarbonate excretion.
• ↑ Oxygen availability to tissues and
placenta.
↑ Kidney size (1 cm).
 • Dilatation of renal pelvis and ureters.

IVP of normal 35 weeks
pregnancy
• ↑Renal Blood flow (60–75 per cent).
 • ↑ Glomerular filtration (50 per cent).
 • ↑ Clearance of most substances.
 • ↓ Plasma creatinine, urea and urate.
 • Glycosuria is normal

Gastrointestinal system


Pregnancy gingivitis
Decrease in the PH& increase in protein conc. of
saliva.

Reduction of lower esophageal
sphincter tone .

Increasing gastric acidity

-Delayed gastric emptying

-Prolonged gastrointestinal transit time
may lead to constipation

-Physical findings such as telangiectasia and palmar erythema appear in up to 60 per
cent of normal pregnancies

-hepatic protein production increased

- an increase in serum alkaline phosphatase secondary to fetal and placental
production is observed in pregnancy.

-s. alanine transaminase &s.aspartate transaminase shown to be lower during
pregnancy,

-LDH unchanged

-the increased production and plasma levels of fibrinogen and the clotting factors VII,
VIII,X and XII.

- plasma cholesterol levels rise by around 50 per cent in the third trimester and
triglycerides may rise to two or three times normal levels.

Pitutery hypertrophy
 Increase prolactine (15 folds higher than
non pregnant)
 Suppression of gonadotrophines


Increase in the production of thyroid binding
globulin.

Increase in the total thyroid hormones.

There is a fall in TSH and arise in the fT4 in the 1st
trimester.

it is followed by a fall in fT4 with advanced
gestations.

Relative deficiency in the iodide.
-↑ total cortisol
-↑Free cortisol
-Loss of diurnal
variation of cortisol
↓
- Production of
placental ACTH
-↑CBG
↓
1- 10 fold increase in
aldosterone &
deoxycocorticosterone
↓
↓
minrelocorticoides
- Increase placental
production
- Increase activiy of renin
&angiotonsine
Increase the level
of ACTH&CRH
↓
Glucocorticoides
Placental
production of
ATH&CRH
Pregnancy specific
↓
-HCG
-HPL
hypothalmas
pituitary
↓
CRH
-GnRH
-
↓
-HGH
-ACTH
-PRolactin
steroids
↓
ostriol
progesterone

Is produced by trophoblast cells.

The B-subunit is pregnancy specific and used
as a sensitive pregnancy test

maintaining the function of the corpus luteum

circulating hCG values reach peak by 10
weeks & fall off after 12 weeks
Pregnancy is
hypermetabolic
state
↙
BMR increased by
(10-20)%
↘
Additional total
energy requirement
is about 300
kcal/day

Is consist of :
1- products of conceptions
2- increase of various maternal tissue
3- increase maternal fat stores

Ranges of weight gain recommended
during pregnancy for women with :

Low BMI (< 20) is 12.5 kg -18 kg

Normal BMI is 11.5 – 16kg

In the first half of pregnancy:
1- fasting plasma glucose concentrations
are reduced
2- little change in insulin levels.

In the 2nd half of pregnancy:
1- an increase in glucose values
2- significant increases in plasma insulin
concentrations

This suggests relative insuline resistance caused
by diabetogenic hormones of pregnancy
After 8th week pregnancy, there is increase
in circulating concentrations of:

triacylglycerols,

fatty acids,

cholesterol

phospholipids all

In early pregnancy:
oestrogen, progesterone and insulin promote the
accumulation of maternal fat stores in early pregnancy
and inhibit lipolysis.
 In
late pregnancy: fat mobilization is enhanced
to allow pregnant women:
- to use stored lipid for energy needs
- Minimize protein catabolism
- preserving glucose and amino acids for the fetus.


total plasma calcium concentrations is decrease
There is little change in the circulating concentration of unbound
calcium

The fetal demand for calcium is about6.5 mmol per day

There are three methods of maternal adaptation to provide
calcium in favour of developing fetus:
1- increasing gut absorption
2- mobilizing skeletal calcium reserves
3-`restricting renal losses.

• Hyperpigmentation.

• Striae gravidarum.

• Hirsuitism.

• ↑ Sebaceous gland activity
Linea nigra
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