Obstetrics

2. Changes occur in:
 CARDIO VASCULAR SYSTEM
 RESPIRATORY SYSTEM
 GASTROINTESTINAL SYSTEM
 URINARY SYSTEM

3. 1.HEART
 The heart is pushed upwards and rotated
by elevation of the diaphragm.
 Apex beat is felt at the fourth intercostal
space and lateral to the midclavicular line.
 Straightening of the left border.
 Exaggerated impression of cardiac
enlargement.
CARDIOVASCULAR SYSTEM

4. Mild increase in size due to increased venous
filling.
Changes in ECG are also seen

5. 2.CARDIAC OUTPUT
 Increase in cardiac output of almost 40%
both due to increase in stroke volume and
pulse rate.
 This begins early in pregnancy and atleast
2/3rds of this increase is in the 1st
trimester.
 Oxygen consumption at rest increases to
meet the needs of fetus and to support the
increased metabolic rate of the mother.

6.  CO increases still more in labour.
15% in 1st stage of labour.
50% in 2nd stage of labour.
 Following delivery there is an immediate rise in
CO due to:
> Relief of inferior vena caval obstruction
> Uterine contraction that empties the blood
to systemic circulation.

7.  CO increases by 60-80% followed by rapid
decline to prelabour value within 1 hour.
 CO returns to normal after 2 weeks following
delivery.

8. 3.BLOOD PRESSURE
 Even though CO increases,there is no
change in BP as peripheral resistance
decreases massively.
 Diastolic Blood pressure falls in the second
trimester and it may return to normal in the
third trimester.

9. 4.SUPINE CAVAL SYNDROME
 Turning from lateral to supine position may
result in a 25% reduction in cardiac output.
 In supine position, pressure of gravid
uterus on IVC reduces venous return to
heart and this leads to fall in the stroke
volume and cardiac output.

10. 5.RENIN ANGIOTENSIN II
 Renin is produced by maternal kidney and
placenta.
 Angiotensinogen is produced by the
maternal and the fetal liver.
 As a result all components of this axis are
increased in normal pregnancy.

11. RESPIRATORY SYSTEM
ANATOMICAL CHANGES
 Lower ribs flare out.
 Subcostal angle increases 68 to 103 degree
 Transverse diameter of the chest increases by
2 cm.
 Diaphragm rises about 4 cm.

12. FUNCTIONAL CHANGES
 Increase in ventilation is achieved by an
increase in Tidal Volume by 40% (500-
700ml)
 Pregnant women does not breath more
frequently, but she breath more deeply.
 No change in vital capacity.

13.  O2 consumption increases by 30-40 ml per
minute to supply the fetus and for extra
metabolism in pregnancy.
Physiological dyspnoea is present due to the
increased tidal volume.
Increased ventilation decreases PCO2 slightly.

14.  The reduced PCO2 from maternal
hyperventilation helps in CO2 transfer from
fetus to mother and facilitates oxygen
release to fetus.
 Functional residual capacity and residual
volume are decreased due to the elevated
diaphragm.
 The total haemoglobin mass and total
oxygen carrying capacities are increased.

15. GASTROINTESTINAL
SYSTEM
ANATOMICAL CHANGES
 Enlarging uterus compresses the rectum
resulting in an increased sensation of need
to defecate.
 Pregnancy displaces the bowels upwards
and sidewise. Tenderness of acute
appendicitis may not be over McBurney’s
point during pregnancy.

16. Lower esophageal sphincter is defunct
resulting in reflux esophagitis.
Haemorrhoids are also common due to
pressure by the gravid uterus.

17. FUNCTIONAL CHANGES
 Nausea and Vomiting
 It is due to reduced mobility of the gut in
pregnancy and by the hCG in circulation.
 Women tend to have better appetite and eat
more.
 They also have strong likes and dislikes for
particular foods termed “pica”.

18.  Increased demand cause increased
absorption of iron and calcium.
 Heart Burn is common due to reflux of acid
secretion into the lower oesophagus.
 Constipation is due to progesterone induced
relaxation of the gut.

19. Gastric emptying is also reduced.
Gallstones occur at a high frequency due to
raised cholesterol level and increased
saturation of bile estrogens.

20. URINARY SYSTEM
ANATOMICAL CHANGES
 Small enlargement in the size of the kidney
and dilatation of the renal pelvis.
 Ureters become atonic and dilated both due to
the pressure of the gravid uterus and the high
progesterone level.
 It makes women more prone to ascending
infection and pyelonephritis.

21. FUNCTIONAL CHANGES
 Renal blood flow increases by 80% in the
second trimester, but falls in the third
trimester.
 GFR increases by 50%.
 Serum creatinine level falls in pregnancy due
to increased renal clearance.

22. Serum urea and uric acid level also
decreases in pregnancy.
Glucose may be present in urine due to
defective tubular reabsorption of glucose
results in lowering of renal threshold in
pregnancy (Nl- 180mg/dl).
5% of pregnant women may show
proteinuria.

23. Exit