3. The Uterus
Size :increase from 7.5 x 5 x 2.5 cm in non
pregnant states to 35 x 25 x 20 cm at term.
Its capacity increases from 10 ml
in non- pregnant state to 5000 ml at term
Weight : increases from 50 gms in
non pregnant state to1000gms at term .
4. The Uterus
Shape :pyriform in the nonpregnant state ,
becomes globular at 8th week , then pyriform by
16th week till term .
Position :the uterus is usually dextroflexed
(deviated to the right) and dextrorotated (twisted
on itself from left to right this due to the
presence of the rectosegmoid colon on the left side
5.
6. The Uterus
Contractility :
start from the first trimester onwards , as
irregular painless contractions ( Braxton –
Hicks contractions).
7. The Uterus
Myometrial changes –
Hypertrophy (estrogen effect) more than
hyperplasia (progesterone effect) till 14th week,
then the fetus exerts a direct stretch.
Formation of Lower Uterine Segment : from the
isthmus and lower half inch of the body. After 12
weeks, the isthmus (0.5cm) starts to expand
gradually to formL.U.S which measures 10cm at
term .
8.
9. The Cervix
1- It becomes hypertrophied , soft and bluish in
colour due to oedema and increased vascularity.
2 - Soon after conception , a thick cervical
secretion obstructs the cervical canal forming a
mucous plug
3- The endocervical epithelium proliferates and
or everted forming cervical ectopy .
10. The Vagina
The vagina becomes soft , warm , moist with
increased secretion and violet in colour due
to increased vascularity.
Increase in mucosal thickness, loosening of
the connective tissue, and hypertrophy of
smooth muscle cells.
11. Changes in the Ovaries
- Both ovaries are enlarged due to increased
vascularity and oedema particularly the ovary
which contains the corpus luteum.
-Corps Luteum : continues to grow till 7 – 8
weeks , then it stops growing, it becomes
inactive and starts degeneration at 12 weeks
(degeneration is completed after labor)
13. increased pigmentation:
•Linea alba becomes linea nigra
•Butter fly pigmentation of the face
•The perineum
Due to increased melanocyte stimulating
hormone or estrogen or ACTH
14.
15. Striae gravidarum : They are
pinkish lines on the abdomen
After labor striae gravidarum
becomes striae albicans (white lines)
17. The Heart
- Position : the apex is displaced upwards and
to the left so that it lies in the 4th intercostal
space outside the midclavicular line as the
diaphragm is elevated progressively during
pregnancy.
-The pulse rate : resting pulse rate increases
by 10- 15 beats/min.
18. The Heart
Heart sounds:
(1) an exaggerated splitting of the first heart sound with
increased loudness of both components.
(2) no definite changes in the aortic and pulmonary
elements of the second sound.
(3) a loud, easily heard third sound.
Murmers :
Systolic functional murmurs may heard over the left sternal
edge .
19. The Heart
ECG Ghanges : No characteristic ECG changes other
than slight left-axis deviation as a result of the
altered heart position.
Cardiac Out Put : increases mainly by increased
stroke volume rather than increased heart rate
reaching a maximum of 40% above the non-pregnant
level at 20 weeks to be maintained till term.
It is directed to the utero placental circulation because
of its low vascular resistance
20. The Vascular System
Arterial Blood Pressure :
decreased in mid trimester to increase again
in 3rd trimester.
This is due to: Decreased Peripheral
resistance (mainly affect diastolic B.P.)
21. The Venous Pressure
Increased venous pressure in the lower limbs due to :
1.Back pressure from the compressed I.V.C. by the
pregnant uterus .
2.Mechanical pressure of the uterus on pelvic veins .
3.Increased venous return from internal iliac veins -
-> increase pressure in external iliac veins.
It predispose to : Oedema , varicose veins and piles
22. The Vascular System
Supine Hypotension:
May occurs in late pregnancy due to
compression on the I.V.C. by the large
pregnant uterus , resulting in decreased
venous return, decreased C.O.P. and low B.P.
to the extent that fainting may occure
24. Blood Volume :it increases steadily from early
pregnancy to reach a maximum of 35-45 % above
the non-pregnant level at 32 week then it plateau.
The increase in plasma volume is more than the
increase in red blood cell mass (Hb mass) resulting
in haemodilution ( physiological anaemia ).
However,the minimal Hb. accepted is 10 – 11gm%
25. White Blood Cells :
increase(from 7.000 / mm3 to 10.500 / mm3 during
pregnancy and up 16.000 / mm3 during labor
26. Coagulation system:
Platelets either increasd or decreased. (controversial).
Fibrinogen doubled to 600 mg %
Factor VIII tripled .
Factor VII & factor X are doubled
Factor XI & factor XIII slight decrease
Fibrinolytic activity decreas.
Therefore pregnancy is a hypercoagulative state . All these changes are
reversed after labour
28. The enlarged uterus displaces the diaphragm up
to ± 4 cm .
This results in :
1. The diaphragmatic mobility is reduced and
respiration becomes mainly thoracic .
2.Widen the subcostal angle and increases the
transverse diameter of the chest
29. Respiratory rate is unchanged during
pregnancy . The functional residual capacity
and the residual volume are decreased as a
consequence of the elevated diaphragm while
the tidal volume increases significantly
31. The kidneys
Renal blood flow and glomerular filtration rate increases by 50
% .
This leads to :
1.There is decrease serum creatinine and uric acid (due to increase
creatinine cleareance) .
2. Decrease blood urea .
3. Increase kidney excretion of glucose due to increase filtration
load and decrease renal threshold leading to renal glucosuria
32. The Ureters
Dilatation of the ureters and renal pelvis due to
:
i - Relaxation of the ureters by the effect of
progesterone and relaxin
ii - Pressure against the pelvic brim by the uterus
particularly on the right side due to dextroposed
uterus and dilatation of the right ovarian vessels .
33. The Bladder
Frequency of micturition in early pregnancy
due to :
i - Pressure on the bladder by the enlarged
uterus .
ii - Congestion of the bladder mucosa .
36. Gingivitis :
There is increased vascularity and tendency for bleeding as well as
hypertrophy of the gum.
Epulis: of pregnancy may develop.
Ptyalism :It is excessive salivation
due to failure to swallow saliva.
37. Nausea and Vomiting ( morning sickness ):
it appears at 4 weeks and disappear spontaneously after 14
weeks It may be hormonal, psychological or allergic.
Appetite Changes :
The pregnant woman dislikes some foods and odours while
desires other
38. Decrease tone and motility all over GIT (progesterone, relaxin
)
• Cardiac sphincter atony, gastro esophageal reflux and Heart
burn
• Decreased Motility of stomach ,Dyspepsia and indigestion
• Decreased Motility of large intestine leading to constipation
• Pyloric sphincter atony leading to regurge of alkaline secretions
from the intestine to the stomach and decreased gastric acidity.
This causes lack of iron absorption and increased iron deficiency
anemia.
39. Haemorrhoids due to :
i - Mechanical pressure on the pelvic veins.
ii - Laxity of the walls of the veins by
progesterone
iii - Constipation.
41. Weight gain :
The average weight gain in pregnancy is 10 - 12
kg.
Out of the 11 kg weight gain
6 kg is composed of maternal tissues (breast, fat,
blood and uterine tissues)
5 kg of fetal tissue , placenta and amniotic fluid.
43. Carbohydrate Metabolism :
Pregnancy is potentially diabetogenic
- Fasting hypoglycemia
-Postprandial hyperglycemia
-hyperinsulinaemia
- Renal glucosuria may occur in the middle of
pregnancy .
