physiological changes during pregnancy.pptx

All about physiological changes

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.

26. CUTANEOUS CHANGES PIGMENTATION : 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.

27. 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.

28. 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 .

29. 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.

30. 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.

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