Physiological Changes during Pregnancy
Genital organs
1. Vulva
Hypertrophy
Oedematous
Hyperemia (more vascular)
Labia minora more pigmented
2. Vagina
Chadwick's sign/Jacquemier's sign
(Bluish discoloration of mucosa).
Hypertrophy
Oedematous
Hyperemia
Secretion; white vaginal discharge due to acidic PH. Prevent multiplication of pathogenic organism (PH 3.5 - 6).
Cytology; Navicular cells in clusters (boat shaped epithelial cell).
3. Uterus
Parts of uterus;
1. Body
2. Isthmus
3. Cervix
1. Changes in Body
Uterus Dimension Pregnant Non-pregnant
Weight of uterus 1000gm 50gm
Thickness 0.6mm 1.5mm
Length 28-32cm 7cm
Width 22-24cm 4cm
Volume 1500ml 10ml
Changes in muscle;
1. Outer; longitudinal
2. Inner; circular
(Sphincter like arrangement around tubal orifices and internal OS.
3. Intermediate; thickest and strongest layer
Arranged in criss-cross (form 8), in between blood vessel run.
4. Hypertrophy and hyperplasia
Increase muscle size and enlargement of organ/tissue.
5. Stretching
Muscle fibres elongated (20 weeks) due to distension by growing fetus.
Uterine wall become thinner at term.
6. Softening of uterus
7. Vascular system
Blood supply; uterine artery, ovarian artery.
Uterine artery (20 weeks) diameter double increases, blood flow increases.
Vasodilation due to estrogen and progesterone.
Vein becomes dilated and valveless.
Numerous lymphatic channel open up.
Vericose vein; when valve not work properly.
Blood collect in legs and pressure builds up.
Valves (one way valves) inside vein help keep blood flowing in right direction.
8. Layers
Ectometrium
Myometrium
Endometrium; changes to decidua
9. Uterus shape
In non-pregnant woman; Pyriform
At 12 week pregnancy; Globular
At 28 week; Oval
At term (36 week); spherical
10. Position
Normal anteverted position.
Errect; 12 weeks
Term; anteverted
11. Contraction
Braxton-Hicks (contraction are irregular, infrequent, spasmodic and painless without any effect on dilatation of cervix.
During contraction complete closure of uterine vein with partial occlusion of artery, may cause diminished placental perfusion; cause transient hypoxia lead to fetal bradycardia.
11. Endometrium
Endometrium in non-pregnant women changes in decidua in pregnancy.
2. Isthmus
During first trimester isthmus hypertrophies.
Isthmus part found during pregnancy.
Elongation and formation of lower uterine segment (12 week).
3. Cervix
Hypertrophy
Hyperplasia
Goodell's sign; marked softening of cervix (6 week).
In non-pregnant woman cervix is hard.
Mucus plug formation; egg like mucus plug formation mixed with blood called show forms in cervical canal in early pregnancy to seal the cervix.
Show; tinged with blood
Operculum; mucus plug
Stroma in cervix;
Hypertrophy and hyperplasia of elastic and connective tissues, composed of fibromuscular collagen protein. Vascularity increased, bluish discoloration.
Increase progesterone breakdown of collagen fibres, cervix dilate and start labor process.
5. Fallopian Tube
Hypertrophy, vascular, length increased.
Epithelium becomes flattened and patches of decidual reaction observed.
Endometrium grow during pregnancy work like mattress/bed provide protection to fetus, act as bed/ mattress.
Implementation of embryo in upper segment of uterus, marked as growth of fundus.
6. Ovary
Hypertrophy
Vascular
Edematous
Ovulation cessation
Oestrogen and progesterone secreted by corpus luteum (13-22 weeks).
7. Breast
Vascularity
Felling of fullness
Hypertrophy of breast
Proliferation of duct and alveoli ducts.
Bluish vein prominent, under skin.
Breast milk; watery secretion, colostrum secretion manually sequeeze (12th week), inactive form because of increase progesterone and decrease prolactin.
At 16 weeks become thick and yellowish.
Hyperpigmentation of primary areola and secondary areola.
Around the nipple (hypertrophy of sebaceous gland) called montgomery's tubercles.
Prickling, tingling, sensation and in around 3-4week.
Nipple becomes larger, erectile and deeply pigmented.
Striation due to stretching of breast skin.
8. Cutaneous changes
1. Chloasma gravidarum or pregnancy mask.
Pigmentation around; check, forehead, around nose, eye.
Disappear spontaneously after delivery.
9. Abdomen
1. Linea nigra
Brownish black pigmented area in midline stretching from xiphisternum to symphysis pubis.
Pigmentation disappears after delivery.
2. Striae gravidarum
Pink stretch mark on abdominal skin.
3. Striae albicans
Silver like stretch mark.
10. Weight gain
Total weight gain during pregnancy; 11 kg
1kg in first trimester.
5kg in second trimester.
5kg in third trimester.
11. Hair growth
During pregnancy 80% hair growth due to diet.
After delivery hair growths falls.
12. Body water metabolism
During pregnancy, retention of electrolytes; sodium, potassium and chlorides and water.
The amount of water retained during pregnancy; 6.5litre.
Pregnancy is a state of hypervolemia.
Causes of increased sodium retention during pregnancy are;
1. Increased estrogen and progesterone.
2. Increase the renin- angiotensin activity.
3. Increases aldosterone
4. Changes in osmoregulation (process by which regulate water and electrolytes).
Polyhydraminos; too much amniotic fluid
Oligohyrominos; too little amniotic fluid
If loss weight; intrauterine growth retardation
13. Haematological changes
Non pregnant Pregnancy (near term) Total increment
Blood volume ; 4000ml 5500ml 1500ml
Plasma volume; 2500ml. 3750ml 1250ml
Red cell volume; 1400ml. 1750ml 350ml
Total Hb(gm). 475. 560. 85
Haematocrit. 38%. 32%. -
(Whole Body)
14. Cardiovascular system
Due to elevation of diaphragm, heart pushed upwards and outward with slight rotation to left, consequent to enlarged uterus.
Pulse rate slightly increase.
Mammary Murmur; continuous hissing murmur (due to increased blood flow).
Through internal mammary vessels (internal thoracic artery).
Doppler echocardiography shows; increase in left ventricular and diastolic diameters.
Cardiac output (CO); increase from 5th week of pregnancy.
CO lowest in sitting or supine position.
CO highest in right or left lateral or knee chest position.
Cardiac output increases during labor, mean arterial pressure (MAP) also rises.
Blood Pressure
Systemic vascular resistance (SVR) decrease due to vasodilation.
Smooth muscle relaxing effect of progesterone, prostaglandins, atrial natriuretic peptide (ANP).
Venous pressure
Distensibility of veins.
Stagnation blood in venus system.
Development of oedema, vericose vein.
Supine hypotension syndrome (postural hypotension).
During late pregnancy; gravid uterus produce compression effect on inferior vena cava, when patient in supine position, result in hypotension, tachycardia, syncope.
Normal BP restore by turning patient to lateral position.
15. Metabolic changes
Metabolism is increased due to needs of growing fetus and uterus.
Protein metabolism
Carbohydrates metabolism
Fat metabolism
Lipid metabolism
Iron metabolism
16. Respiratory system
With enlargement of uterus; elevation of diaphragm by 4 cm.
Increase 18-20 breaths due to increase cardiac output.
Pregnancy is a state of respiratory alkalosis.
Maternal O2 consumption increased due to increase demand of fetus, placenta and maternal tissue.
17. Urinary system
Hypertrophy of uterus, renal pelvis, calyces.
Increase frequency of urination at 12 week.
GFR (glomerular filtration rate) increased throughout pregnancy.
Increased GFR causes reduction in maternal plasma level of creatinine, blood urea nitrogen (BUN), uric acid.
Frequency problem relieved after 30 weeks, because descend of fetus.
Ureters;
Ureters become atonic cause dilatation and elongation of ureters due to high progesterone level.
Stasis of ureters can cause due to UTI.
Stress incontinence may late in late pregnancy due to urethral sphincter weakness.
Renal function;
GFR increases.
Rate of urine formation increases.
Dilatation of ureters, Renal pelvis, calyces
Kidney enlarge in length; 1cm.
18. Gastrointestinal system
Gum becomes spongy; may bleed to touch.
Cardia sphincter relax; due to increase progesterone.
Delay empty of stomach/ diminished gastric secretion.
Morning sickness/nausea/vomiting due to increase hCG.
Regurgitation of acid gastric content.
Heart burn/oesophagitis.
Muscle tone and motility of entire gastrointestinal tract diminished.
Risk of peptic ulcer disease reduced.
Atonicity of gut lead to constipation.
When uterus grow enter into abdominal cavity, and also press on parts of digestive tract and displaced backward leads constipation.
Straining can cause hemorrhoids/anal fissure/ piles.
19. Calcium metabolism
Increase need of calcium by growing fetus.
Calcium absorption from intestine and kidney are doubled due to rise in level of vitamin D.
18. Lordosis in pregnancy
(Inward curvature of lumbar spine)
Pregnant woman moves towards abdomen, resulting in an increase in lumbar lordosis (occurs in late 2nd and early 3rd trimester).
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