The document outlines the physiological changes that occur during a normal pregnancy, which lasts about 40 weeks and is divided into three trimesters. It details transformations in the reproductive system, cardiovascular, metabolic, respiratory, urinary, gastrointestinal, endocrine, and integumentary systems, emphasizing changes such as increased blood volume, altered hormonal levels, and physical adaptations of organs. Additionally, it includes information on weight gain trends and skin changes during pregnancy.

1. PHYSIOLOGICAL
CHANGES DURING
PREGNANCY

2. NORMAL PREGNANCY
 Pregnancy is the term used to describe the period in
which a fetus develops inside a woman's womb or uterus.
A normal pregnancy last about 40 weeks and grouped
into 3 trimesters.
 Pregnancy is roughly divided into 3 stages known as
trimesters of about 3 months each : first trimester –
conception to 12 weeks. second trimester – 13 to 27
weeks. third trimester – 28 to 40 weeks.

3. REPRODUCTIVE SYSTEM
Genital organs
 Vulva
-Oedematous
-Hyperaemic
-Labia minora pigmented and hypertrophied
 Vagina
-Vaginal wall hypertrophied,oedematous and
more vascular
-Bluish discolouration of the mucosa
(jacquemier’s sign/chadwick’s sign)

4. -The length of anterior vaginal wall is increased
 Secretion
-Copious, thin and curdy white
-The ph becomes acidic (3.5-6)
 Uterus
-The uterus in non pregnant state measures about
7.5 cm in length and 50 gram.
-At term weighs 900-1000 gm and measures 35 cm
in length.
-Changes occurs in the body, isthmus and cervix of
the uterus.

5.  Body of the uterus
-There is increase in the growth and enlargement
of the body of uterus.
-It is due to changes in the muscles as a result of
progesteron and oestrogen. It causes
hyperplasia and hypertrophy of muscle fibers.
>Vascular system
-spiraling of the uterine arteries are more
pronounced at the placental site.
>Weight
-Weight of the uterus is increased due to the
increased growth of the uterine
muscles,connective tissue and vascular
channels.

6. >Shape
-Uterus becomes globular at 12 weeks oval by
28 weeks, spherical beyond 36 wks.
>Position
-The enlarged uterus may lie on the bladder,
afterwards it becomes erect.
>Endometrium
The endometrium of the pregnant uterus is
called decidua. It differentiated into 3
layers.
-superficial compact layer
-intermediate spongy layer
-thin basal layer

7.  Isthmus
>During first trimester : It hypertrophied and
elongates .
>Beyond 12 wks :The circularly arranged muscle
fibers around the cervix function as a sphincter
in early pregnancy and helps to retain the fetus
with in the uterus.
 Cervix
-There is hypertrophy and hyperplasia of the elastic
and connective tissues.

8. BODY WATER METABOLISM
 During pregnancy the amount of water
retained at term is about 6.5 liters .
 The water content of the fetus,placenta, and
amniotic fluid is about 3.5 liters.
 There is active retention of
sodium ,potassium and water.

9. HAEMATOLOGICAL CHANGES
 Blood volume : is raised during pregnancy from
6 th wk.
 Plasma volume :Total plasma volume is
increased to the extend of 1.25 liters.
 RBC and haemoglobin :increase in volume about
350 ml.
 Leucocytes :Neutrophilic leucocytosis occurs to
the extend of 20,000/cu mm in labour.
 Total plasma protein :increases from normal 180
gm to 230 gram.

10.  Blood coagulation factors
-Fibrinogen level is raised
-ESR raises
-Platelet count is raised
-Increased in activities of clotting factors like
IX,VII, VIII, and II.

11. HEART AND CIRCULATION
 Due to the enlargement of the uterus the
diaphragm is elevated and the heart is
pushed upwards and outwards.
 Cardiac output increases by 5 th wk of
pregnancy.
 Blood pressure is decrease due to relaxing
smooth muscle effect of progesteron ,nitrous
oxide and prostaglandins.

12.  Venous pressure
-Femoral venous pressure is increased from 8-10 cm
of water in non pregnant state to about 20 cm of
water in pregnancy.
 Supine hypotension syndrome(postural
hypotension)
-During late pregnancy the gravid uterus produces a
compression effect on the inferior vena cava when
the patient in supine position.
-This result in production of hypotension,
tachycardia and syncope.
-The normal blood pressure is quickly recovered by
turning the patient to lateral position.

13. METABOLIC CHANGES
The metabolism is increased due to the needs of
the growing fetus and uterus.
 Protein metabolism
-As the breakdown of the aminoacid to urea is
suppressed the blood urea level is falls to 15-20
mg %.
-Amino acids are actively transported across the
placenta to the fetus.
-Maternal gain of protein is about 500 gm
(distributed in the uterus ,breast and maternal
blood.)

14. Carbohydrate metabolism
 Transfer of increased amount of glucose from
mother to fetus .
 Insulin secretion is increased
 Hypertrophy and hyperplasia of beta cells of
pancreas.
 Plasma insulin level is increased due to
oestrogen ,progesteron,human placental
lactogen,cortisol and prolactin.

15. Fat metabolism
 An average of 3-4 kg of fat stored during
pregnancy mostly in the abdominal wall ,
breast, hips and thighs.
Iron metabolism
 Iron is absorbed in ferrous form from
duodenum and jejunum and is released in to
the circulation as transferrin.
 Total iron requirement during pregnancy is
estimated approximately 1000 mg.

16. SYSTEMIC CHANGES
Respiratory system
 A state of hyperventilation occur during pregnancy
leading to increase in tidal volume (Amount of air
enter in to the lungs). It is due to progesteron
acting on the respiratory center.
Acid base balance
 The hyperventilation causes changes in the acid
base balance.
 The arterial PaCo2 falls from 38 to 32 mm Hg and
Pa O2 rises from 95mm Hg to 105 mm Hg.
 These facilitate transfer of Co2 from the fetus to
the mother and O2 from the mother to fetus.

17. URINARY SYSTEM
Kidney
 Dilatation of the ureter and renal pelvis.
 The kidneys enlarge in length by 1 cm.
 Glomerular filtration rate is increased.
Ureter
 Dilatation of the ureter above the pelvic brim.
 Ureter become atonic due to high progesteron
level.
 Hypertrophy of the muscles of the ureter due
to oestrogen

18. Bladder
 Congestion with hypertrophy of the muscles and
elastic tissues of the wall.
 In later pregnancy the bladder mucosa becomes
oedematous.
 Frequency of micturition in later pregnancy due
to pressure on the bladder by the presenting
part.

19. ALIMENTARY SYSTEM
 The gums become congested and spongy may
bleed to touch.
 Muscle tone and motility of the entire
gastrointestinal tract are dimnished due to
progesteron level.
 Cardiac sphincter is relaxed and regurgitation
of gastric acid content in to the oesophagus
may produce heart burn.

20. Liver and gallbladder
-Atonicity of the gallbladder
-Changes in the liver alkaline phosphatase.

21. NERVOUS SYSTEM
 -Nausea, vomiting ,mental irritability,
sleeplessness due to some psychological
background.
 Compression of median nerve under the
carpal ligament over the wrist joint lead to
pain and parethesia in the hands and arm.
(Carpal tunnel syndrome)

22. ENDOCRINE SYSTEM
Pituitary gland
 During normal pregnancy the pituitary increases in
size and weight.
 Pituitary gonadotrophin levels are low due to
increased levels of oestrogen and progesteron.
The thyroid
 Hyperplasia and slight enlargement of the thyroid
gland.
 Renal clearance of iodine is increased due to
increased glomerular filtration rate.
 Maternal iodine level fall due to increased renal
loss and also transplacental shift to the fetus.

23.  Iodine intake during pregnancy should be increased
from 100 -150 microgram/day to 200
microgram/day
The adrenal cortex
 There is slight enlargement of the adrenal cortex.
 There is increased in the serum level of
aldosterone, deoxycorticosterone and cortisol.
The parathyroid gland
 Maternal parathyroid hyperplasia occurs during
pregnancy .
 The concentration of parathyroid hormone is
normal during pregnancy.
Pancreas
 In pregnancy there is hyperinsulinism particularly
during 3 rd trimester.

24. BREAST CHANGES
SIZE:
 Increased size of the breasts.
 This is due to marked hypertrophy and
proliferation of the ducts (estrogen) and the
alveoli (estrogen and progesterone)
 There is also hypertrophy of the connective
tissue stroma.
 Myoepithelial cells become prominent.
 Vascularity is increased which results in
appearance of bluish veins running under the
skin.
 There may be evidence of striation due to stretching
of the cutis

25. NIPPLES AND AREOLA:
 The nipples become larger, erectile and deeply
pigmented.
 Variable number of sebaceous glands (5–15) which
remain invisible in the nonpregnant state in the
areola, become hypertrophied and are called
Montgomery’s tubercles.
- Those are placed surrounding the nipples.
- Their secretion keeps the nipple and the areola
moist and healthy.
- An outer zone of less marked and irregular
pigmented area appears in second trimester and is
called secondary areola.

27. CUTANEOUS CHANGES
PIGMENTATION:
1. Face (chloasma gravidarum or pregnancy mask):
It is an extreme form of pigmentation around the
cheek, forehead and around the eyes.
- It may be patchy or diffuse; disappears
spontaneously after delivery.

28. Abdomen:
Linea nigra:
 It is a brownish black pigmented area in
the midline stretching from the
xiphisternum to the symphysis pubis.
 The pigmentary changes are probably due
to melanocyte stimulating hormone from
the anterior pituitary. However, estrogen
and progesterone may be related to it. The
pigmentation disappears after delivery.

29. Striae gravidarum:
 They are predominantly found in the
abdominal wall below the umbilicus,
sometimes over the thighs and breasts.
Striae gravidarum: reddish or purple lesions
that develop due to overstretching of the
abdominal skin as the gravid uterus expands
(commonly referred to as stretch marks).
 Striae albicans: mature stretch marks which
appear silver-like in colour and are less
pronounced.

31. WEIGHT GAIN
WEIGHT GAIN:
 In early weeks, the patient may lose weight
because of nausea or vomiting.
 During subsequent months, the weight gain is
progressive until the last 1 or 2 weeks, when
the weight remains static.
 The total weight gain during the course of a
singleton pregnancy for a healthy woman
averages 11 kg (24 lb).
 This has been distributed to 1 kg in first
trimester and 5 kg each in second and third
trimester.

32. REFERENCES
 Dutta D.C; Text book of obstetrics; sixth
edition Kolkata, new central book agency (P)
LTD , 2004;
 Jacob Annamma ;A comprehensive text book
of midwifery ;First edition, new delhi.
Jaypee brothers medical publishers (P) LTD,
2005 .
 Fraser .diane M; myles text book for
midwives; fifteenth edition, elesevier
publications limited,2009.

33. THANK YOU