Physiological changes in pregancy- 2021

Physiological changes in pregancy
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Physiological changes in pregancy


During pregnacy there are progress anatomical and psychological changes

These changes does not occur at the general organs but also to all the system of the body.

This is due to increasing  demands of the growing fetus


I. Changes in gential organs


1. Vulva

– It becomes edematous and hyperemic

– The labia minora become pigmented and hypertrophed.


2. Vagina

– It becomes hypertrophied vascular and edematous

– The vaginal secretion becomes coupon, thin and curly white

– The PH becomes more acidic


3. Uterus

– There is increase in size of uterus

– It measures 35 cms in length and 900-1000 gms

Changes occurs in all the parts of uterus

– The uterine muscles undergo hypertrophied and hyperplasia

– The fundus enlarged more than the body of the uterus.

– The 3 distinct layer if uterus muscles can be made out.

– In a turn the uterus differentiate into an active upper segment which is more muscluar and a passive lower  segment which is least muscular.

– The cervix is deviated to the left side, bringing it closer to the ureter due to lateral obliquity.


II. Breast

There is increase in the size of the breast due to hypertrophy and proliferation of the ducts alveoli.

The vascularity increase which result in the appearance of bluish vein running under the skin.

The nipple becomes larger, erctile and are deeply pigmented.

The sebaceous glands which remains invisible in the non- pregnant state becomes hyoertropheid over the aerola during pregnancy and are called as montgomery’s tubercles.

Secondary areola is seen in the 2nd trimester.

Secretions may also been seen at about 12 week of pregnacy

Breast weight is increased approximately to 500-800gm.


III. Endocrine system

– Changes are brought about by progesterone, estrogen and relaxin hormones.


a. Effect of progesterone

– Reduction in tone of smooth muscles resulting in nausea, reduced peristalsis, constipation, bladder toned is decreased, dilation of veins and decreased diastolic pressure.

– Increased in body temperature

– Development of breast alveolar & glandular milk producing cells.


b. Effects estrogen

– Increased growth of uterus and breat duct

– Increased levels of prolaction for lactation

– Material calcium metabolism

– Higher level  may result in increased vaginal glycogen resulting in thrush


c. Effects of relaxin

– Replacement of collagen  in pelvic joint, capsule, cervix, resulting in greater extensibility, liability.

– Inhalation of myometrial activity.

– Helps in distension of uterus and provides additional supporting connective tissues.

– Has a role in cervix ripening

IV. Cutaneous changes:

There is formation of cholsma gravidum or pregnacy mark in the form of pigmentation around the check which us patchy or diffused and it disappears after delivery.

It also shows formation of linea nigra which is a brownish black pigmentation in the midline of the abdomen stretching from the xiphisternum to the public symphysis.

It is usally disapper after delivery.

Striae gravidarum are normally slightly depressed  linear marks with varying length & breath. These are seen just below the umbilicus.

These are pinkish during delivery which becomes glistening white after pregnacy and is then called as striae albicans.


V. Weight gain

A pregnant lady puts on about 10-12 kg of weight.

In early pregnancy the lady may loose weight due to nausea and vomiting but later the weight gains is progressively imcreased to about 2 kg every month.


VI. CVS changes

Increase in blood volume by 40%

Increased in plasma level than red cells and Hb level falls by 80%. This is called as physiological anemia due to pregnacy.

During 3rd trimester, the weight of fetus may compress the aorta and IVC against the lumbar spine  in lying position causing dizziness, unconsciousness and is called as pregnacy hypertensive syndrome.

Increased in cardiac output by 40%

Stroke volume increased by 30%

Heart rate increased by 30%

Heart rate increased by 15 beats / min


VII. Respiratory system

Respiratory rate increases from 15-18 breath/min

Alveolar ventilation increases

Tidal volume increased upto 40%

Diaphragm is raised by 40 mm

Chest diameter is increased by 20 mm

Co2 tension is decreased

PaO2 – 92 mm of Hg

PaCo2 – 30 mm of Hg


VIII. GIT  and uninary system

Nausea and vomiting due to response by human  chronic gonadotrophin.

 •Delayed gastric emptying and thus shows constipation

Increased concentration of bile in gall bladder.

There is increased in the size and weight of kidney and dilation of the renal pelvis.

Dilation of ureter causes pooling and stagnation of urine resulting in U.T.I


IX. Musculoskeletal system

Increased joint laxity

Increased lumbar lordosis due it changes in COG and pelvic tilting.

The distance between the two rectus abdominal muscles widens and the linea alba may split under the strain called as diastasis recti.

Edema of ankle due to water retention

Compression of nerves causing carpel tunnel syndorme.


X. Psychological and emotional changes

 Mood swings



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