Physiological changes in pregnancy

1. PHYSIOLOGICAL
CHANGES IN
PREGNANCY

2. VULVA:
• Oedematous, more vascular
• Superficial varicosities may appear
more
• Labia minora- pigmented and
hypertrophied
VAGINA :
• Oedematous, increased
vascularity
• Hypertrophied
• CHADWICK SIGN / JACQUEMIER
SIGN- Bluish discolouration of
vulva/ vagina due to increased
vascularity at 8th
week of
gestation.
• Increased volume of vaginal
discharge
thick and whitish discharge
Acidic pH (3.5-6)
REPRODUCTIVE TRACT CHANGES

3. CERVIX:
Hyperplasia and Hypertrophy of elastic tissue, connective tissue and cervical
glands.
Lead to marked softening of cervix (GOODELL’S SIGN) , by 6 weeks of pregnancy
Marked proliferation of endocervical mucosa with downward extension beyond
Squamocolumnar junction
Erosion ( ectopy ) cervix
These can also become hyperactive and mucosal changes and stimulate basal cell
hyperplasia or CIN.
Which regress spontaneously after delivery.

4. • CERVICAL SECRETIONS:
Rich in Immunoglobulins and cytokines-
acts as barrier to protect uteric contents
against infections.
BEADING – In some female as a result of
progesterones cervical mucus show poor
crystallization on glass slide.
FERNING – Due to amniotic fluid leakage ,
cervical mucus shows arborization of Ice like
crystals.
ENDOCERVICAL GLAND HYPERPLASIA
+
HYPERSECRETORY APPEARANCE OF
CERVICAL GLANDS – ARIAS STELLA
REACTION.

5. ISTHMUS :
Area between anatomical and
histological internal Os.
Till 12 weeks – Hypertrophies and
elongates to 3 times its original
length
After 12 weeks – It progressively
unfolds from above downwards and
circularly arranged muscle fibres ,
they function as sphincter and help to
retain fetus in uterus

6. UTERUS
In non pregnant uterus~ 70 grams, almost solid, volume is 10 ml.
In pregnant uterus~1100 grams, thin walled muscular organ of capacity 5L to 20L.
TILL 12 WEEKS-Uterine enlargement is due to- uterine hypertrophy and hyperplasia with fibrous tissue
accumulating in external muscle layer.- Gradually term Myometrium- 1-2 cms.
AFTER 12 WEEKS- Growth of uterus is due to pressure exerted by expanding products of conception.
MAXIMUM ENLARGEMENT- Occurs in Fundus of Uterus.

7. MYOCYTE ARRANGEMENT: 3 Strata
1. Outer hood like layer- over the
fundus.
2. Middle dense muscular fibres
3. Sphincter like fibres- Around fallopian
tube and internal os.
Myocyte has a double curve , so
interlacing any of the 2 cells for a figure
of eight.

8. UTERINE SHAPE AND POSITION.
• 1st
Few Weeks- Original Piriform/ Pear shape
• By 12th
week- corpus and fundus become
globular and it extends into pelvis
• Beyond 36 weeks- Spherical
Uterus – DEXTROROTATION (due to rectosigmoid on
left side of pelvis)
UTERINE CONTRACTILITY.
Braxton Hicks Contractions are irregular , spasmodic,
painless contractions without any dilatation of cervix.
Intrauterine pressure- <8mmhg.
Changes in uterine shape

9. VASCULAR SUPPLY-
In Non pregnant state- Main blood supply is
from Uterine Artery.
In Pregnant state- Blood supply from both
Uterine Artery and Ovarian Artery.
Due to Estradiol and Progesterone veins become
dilated and valveless leading to Vasodilatation.

10. OVARIES : During pregnancy maturation of follicle is suspended
Corpus Luteum- It contributes to progesterone production till 12 weeks of
gestation and found Maximum during 6-7 weeks of pregnancy (~2.5 cm)
Till 7 weeks , surgical removal of corpus leutum- will cause rapid fall in
progesterone levels and spontaneous abortion, and it causes decrease in
Relaxin and Hcg.
Theca luetein cysts- HYPER REACTIO LUTEIN REACTION are exaggerated
physiological follicle stimulation . B/L Ovaries are involved.
Linked with marked increased in serum Hcg levels.

11. Theca leutin cysts Can be found in:
• Normal pregnancy
• Placentomegaly accompanying Diabetes Mellitus, Anti D alloimmunization,
Multifetal gestation.
• Pre eclampsia and hyperthyroidism
Fallopian tube:
Musculature of fallopian tube (hydrosalpinx) undergoes hypertrophy during
pregnancy endoslpinx become flat.
Decidual cells may develop but a continuos membrane is not formed .

12. SYSTEMIC CHANGES:
1. Respiratory Changes-
Increase in- Tidal Volume
Inspiratory capacity
Minute Oxygen uptake
Minute ventilation(40%)
Decrease in- Functional Residual
Capacity
Expiratory Reserve
Volume
Residual Volume
Total Lung Volume
No Change- Respiratory rate
Vital Capacity
Inspiratory reserve volume

13. Mild respiratory alkalosis(compensated)
Diaphragm rise by 4 cms and increase in transverse thoracic diameter by 2 cms
2. GIT-
• Due to increase in progesterones decrease in tonr of lower esophageal
sphincters and increase in gastric pressure leading to increase in GERD.
• No change in gastric emptying time
LIVER: Total Protein increases
S. Protein concentration decreases
Oncotic Pressure decreases ( leading to physiological edema)
ALP increases physiologically
AST/ALT- decreases
(But in HELLP syndrome AST/ALT increases)

14. 3. Renal changes:

15. • Renal Plasma Flow-increases
• Glomerular Filteration Rate – increases
• S. Creatinine – decreased
• BUN- decreased
• Uric Acid- decreased
• Physiological Hydroureter- due to high levels of progesterones

16. 5. HEMATOGICAL CHANGES :
• Blood volume- Raised (progressively and inconsistently)
6th
week of gestation –
maximum (40%-50%)
above the non pregnant levels at 30-34 weeks of gestation.
• Plasma volume- Raised Maximum- 50%)
6th
week of gestation –
plateau- 30 weeks
Total plasma volume- increases to 1.25 L
• RBC and Hemoglobin- Raised to 20%-30%
Starts to increase from 10th
week of gestation and continues till
term without plateauing.
RBC mass increases - 30%
Reticulocyte Count increases - 2%

17. Disproportionate increase in plasma and RBC volume – Hemodilution (fall in hematocrit)
• Leucocytes and immune system- Neutrophilic leucocytosis( due to estrogen and
cortisol) .
Suppression of humoral and cell mediated immune system- transition to antibody
mediated immunity.
• Total Plasma Protein:

18. • Blood Coagulation Factors- HYPERCOAGULABLE STATE
Clotting factors ( 1,7,8,9,10) – Increase
Clotting Factors(2,5,12)- Unchanged/ Mild Increase.
Clotting factors (11,13)- slightly decreased
Overall , effective to control blood loss and hemostasis.

19. 5. CARDIOVASCULAR CHANGES :
Anatomical- Heart pushed upward and outward- slight
rotation to left.
Abnormal clinical findings-
• Apex Beat- shifted to 4th
intercostal space
• Pulse rate- slightly raised
• Systolic murmur- in apical or pulmonary area
• Mammary murmur- Over the tricuspid area
• S3 may be heard
• Doppler echocardiography- Increase in LVED
diameters
• ECG- normal- LAD

20. Cardiac output-
• Cardiac output= stroke volume x
heart rate
• CO, during labour- increases by 50%
Immediately following delivery-
increases by 70%
Blood Pressure-
• BP= CO x SVR
• BP decreases , MAP decreases by 5-
10mmhg
• SVR decreases , due to smooth
muscle relaxation.

21. Venous Pressure-
• Antecubital VP unaffected
• Femoral VP- markedly raised.
Central hemodynamics-
• Blood volume, cardiac output, heart rate increase
• SVR, PVR, Colloidal osmotic pressure significantly fall
• Therefore, CVP and MAP PCWP – NO SIGNIFICANT CHANGE

22. Regional distribution of blood flow:
Progesterone, estrogen, nitric oxide, prostaglandins, ANP
SMOOTH MUSCLE RELAXATION –> VASODILATATION
UTERINE BLOOD FLOW – 50ml/min to 750ml near term (uteroplacental and fetoplacental
vasodilatation)
Pulmonary blood flow +2500ml/min
Renal blood flow + 400ml/min at 16th
week and remains till term
Skin and mucous membrane – 500ml/min by 36th
week
Heat sensation , sweating and stuffy nose

23. SUPINE HYPOTENSION SYNDROME: