Physiological changes during pregnancy

presentation on physiological changes during pregnancy.

1. PHYSIOLOGICAL CHANGES DURING PREGNANCY Anju Bista MSc nursing

2. Pregnancy is very crucial, during pregnancy there is progressive anatomical, physiological and psychological changes occur in genital organs including all systems of body. It is phenomena of maternal adaptation towards changes in the body with increasing demand of growing fetus Introduction

3. Changes in body system

4. Genital organs:- vulva:- vulva becomes oedematous and more vascular; superficial varicosities may specially in multi – parae . libia minora are pigmented and hypertrophied. Changes in reproductive system

5. Vaginal walls becomes hypertrophied , oedematous and more vascular.increased blood supply the venous plexus surrounding the walls gives the bluish coloration of mucosa( jacquemier’s sign). Pulsation of the uterine arteries feels through the lateral fornices called osiander’s sign. The length of the anterior vagina wall is increased . Vagina:-

6. T he secretion becomes copious, thin and curdy white due to marked exfoliated cells and bacteria. The ph becomes more acidic(3.5- 6) due to more conversion of glycogen into lactic acid by the lactobacillus acidophilus. Contd …

7. There is enormous growth of the uterus during pregnancy .after conception ,the uterus develops to provide a nutritive and protective environment in which the fetus will develop and growth . The uterus which in non pregnant state weight about 60 gm, with a cavity of 5- 10 ml and measures about 7.5 in length, at term ,weights 900-1000gm and measures 35cm length . Uterus :-

8. The capacity is increased by 500 to 1000 times. Changes occur in all the part of the uterus body ,isthmus and cervix. Uterus Contd …

9. There is increase in growth and enlargement of the body of the uterus. The uterine enlargement is not a symmetrical one. The fundus enlarges more than the body . The enlargement of the uterus is affected by the following factors: Changes in muscles Hypertrophy and hyperplasia. Stretching.  Uterine ligaments show hypertrophy. Body of the uterus :

10. Dextro -rotation:- the uterus is tilted and twisted to the right in 80% of case. Lower uterine segment (LUS) the LUS is formed from the isthmus formed from the 4th month to reach 10 cm at full term . Contd...

11. The deciduas is a name given to the endometrium during pregnancy ; progesterone and estrogen initially produces by corpous luteum causes the deciduas to become thicker and richer and more vascular at the fundus and in the upper body of uterus. The decidua provides a glycogen rich environment for the bastocyst until the trophoblast cells begins to form the placenta. When placenta is formed; it is able to produce its own hormone. Deciduas :

12. Estrogen is responsible for the growth of uterine muscle. Increased in size of the muscle fibers is known as hypertrophy and increase in their number is referred to as hyperplasia . Myometrium :

13. The uterus is able to stretch in this way because progesterone encourages relaxation of smooth muscle. After 16 weeks of gestation, uterus begins to generate small wave of contraction known as Braxton hick’s contraction which is painless although some women experience pain. Myometrium contd …

14. It is a layer of peritoneum. It does not totally cover uterus.it allows for the unrestricted growth of uterum . Perimetrium :

15. There is structural and functional change in the isthmus during pregnancy. During 1 st trimester , isthmus hypertrophies and elongates to about 3 times its original length. With advancing pregnancy beyond 12 weeks, it progressively unfolds from above, downward until it is incorporated into the uterine cavity It’s become softer . Isthmus:

16. The cervix becomes soft and secretes more mucus. Its color changes from pink to bluish due to more vascularity.There is hypertrophy and hyperplasia of the elastic and connective tissues. The cervix undergoes a marked softening which is referred to as the Goodell's sign."It begins at the margin of the external os and then spread upwards . Cervix:

17. It serves to seal the uterus and to protect the fetus and fetal membranes from infection. The mucus plug is expelled at the end of the pregnancy. This may occur at the onset of labor or precede labor by a few days. When the mucus is blood-tinged, it is referred to as a "bloody show’’. Additional changes and softening of the cervix occur prior to the beginning of labor. Contd …

18.   It is placed almost vertical by the side of the uterus. At term,its attachment to the uterus is placed at the lower end of the upper 1/3 rd ,because of the marked growth of the fundus .   Fallopian tube:

19. Ovary looks bright orange, later on becomes yellow and, finally pale. Regression occurs following decline in the secretion of human chorionic gonadotropin ( hCG ) from the placenta. The follicle-stimulating hormone (FSH) ceases its activity due to the increased levels of estrogen and progesterone secreted by the ovaries and corpus luteum . The FSH prevents ovulation and menstruation . Ovary:

20. The corpus luteum produces progesterone which helps maintain the lining of the endometrium in early pregnancy It functions until about the 10th to 12th week of pregnancy when the placenta is capable of producing adequate amounts of progesterone and estrogen. It slowly decreases in size and function after the 10th to 12th week Contd …

21. The changes in the breast are best evident in a primi gravida . In multipara who has once lactated , the changes are not clearly defined. During pregnancy , the breast changes in both size and appearance. Breast:

22. The increases in size is due to the effects of estrogen and progesterone. Estrogen stimulate the growth of mammary ductal tissue, progesterone promotes the growth of lobes ,lobules and alveoli. Fullness, tingling and heaviness of the breast begin in the early weeks of gestation in response to increased level of estrogen and progesterone. Contd …

23. Changes in circulatory system

24. Blood volume : The blood volume starts to increase from about 6 th week;expands rapidly thereafter to maximum 40-50% above the non pregnant level at 30-32 weeks . Plasma volume: total plasma volume increases by 1250ml. RBC: it is increased to the extent of 20-30%,ie by 350ml. Haematological changes :

25. Hemoglobin : it increases by 18-20%,ie by 85 gm. Neutrophilic leukocytosis occurs to the extent of 10-15000/cu mm and even to 20,000/cu mm in labour . Platelets level decrease up to 15% than in non-pregnant state. Cntd …

26. Even though the total Hb mass increases during pregnancy, there is apparent fall in total hb concentration .At term, the fall is about 2 gm % from the non pregnant value.

27.   Non pregnant Pregnancy near term change Blood volume 4000 5500 1500 Plasma volume 2500 3750 1250 Redcell volume 1400 1750 350 Hb 475 560 85

28. Heart and c irculation:

29. Due to elevation of the diaphragm consequent to the enlarged uterus, the heart is pushed upwards and outwards with slight rotation to left . Anatomical Change:

30. The cardiac output starts to increase from 5 th week of pregnancy, reaches its peak 40-50 % at about 30-34 weeks. Cardiac output is lowest in sitting or supine position and highest in left or left lateral or knee chest position Cardiac output increases further during labour (+50%) and immediately following delivery(+70%) over the pre- labour values Cardiac output returns to pre- labour values by One hour following the delivery and to pre-pregnant value level by another 4 week time. Cardiac output

31. The increase in cardiac output is caused by: Increased blood volume. To meet the additional oxygen required due to increased metabolic activities during pregnancy. The increase in cardiac output is chiefly affected by increase in stroke volume and pulse rate.

32. Systemic vascular resistance (SVR) decreases due to the smooth muscle relaxing effect of progesterone, NO, prostaglandins. In-spite of large increase in cardiac ouput , maternal B.P decreases due to decrease in SVR. There is overall decrease in diastolic blolod pressure (DBP) and Mean Arterial Pressure (MAP) by 5-10 mm ofHg . Blood pressure:

33. Femoral venous pressure is markedly raised specially in later months. It is due to the pressure exerted by the gravid uterus on the common iliac veins, more on the right side due to the dextro -rotation of the uterus . V enous pressure:

34. Non-pregnant Pregnant change Cardiac output(co) ( litre/min ) 4.5 6.26 +40% Stroke volume(ml) 65 75 +27% Heart rate (/min) 70 85 +17% Venous pressure 8-10cm H2o 20cmH2o +100% Systemic vascular resistance -21%   H aemodynamic changes during pregnancy:

35. Uterine blood flow is increased from 50ml/min in non pregnant state to about 750 ml(near term). The increase is due to the combined effect of utero-placental and feto -placental vasodilatation. Renal blood flow (normal 800 ml) increases by 400 ml/min at 16 th week and remains at this level till term. The blood flow through the skin and mucus membrane reaches a maximum of 500ml/min by 36 th week . R egional distribution of blood flow:

36. With the enlargement of uterus, especially in later months, there is elevation of the diaphragm(4cm) and breathing becomes diaphragmatic. Respiration :

37. Mucosa of the upper respiratory tract shows hyperaemia and congestion .A state of hyper ventilation occurs during pregnancy leading to increase in tidal volume. It is probably due to the progesterone acting on the respiratory centre and also to increase in sensitivity of the centre to carbondioxide . The women feels shortness of breath. Contd …

38. NON PREGNANT PREGNANCY NEAR TERM CHANGE Respiration rate 15 15 unaffected Vital capacity 3200 3300 Almost unaffected Tidal volume 475 675 +40% Residual volume 965 765 -20% Total lung capacity 500 4750 -5%

39. Urinary system :

40. Striking anatomical and physiological changes are seen in the urinary system comprising of the kidneys ,ureters and the urinary bladder with the enlargement of the uterus.

41. During pregnancy , each kidney increases in length by 1-1.5cm, with a concomitant increase in weight. The renal pelvis is dilated. The ureters are dilated above the brim of the bony pelvis. The ureters also elongate, widen, and become more curved. Thus there is an increase in urinary stasis, this may lead to infection. Renal Dilatation

42. The absolute cause of hydro nephrosis and hydro ureter in pregnancy is unknown, there may be several contributing factors :  Elevated progesterone levels may contribute to hypotonia of the smooth muscle in the ureter. The ovarian vein complex in the suspensory ligament of the ovary may enlarge enough to compress the ureter at the brim of the bony pelvis, thus causing dilatation above that level.

43.   The glomerular filtration rate(GFR) increases during pregnancy by about 50% . The renal plasma flow rate increases by as much as 25-50%. Even though the GFR increased dramatically during pregnancy, the volume of the urine passed each day is not increased. With the increase in GFR, there is an increase in endogenous clearance of creatinine . Renal Function:

44. Increased levels of urinary glucose also contribute to increased susceptibility of pregnant women to urinary tract infection. Proteinuria changes little during pregnancy and if more than 500mg/24hour is lost, a disease process should be suspected. Contd …

45. Levels of the enzyme renin, which is produced in kidney, increase early in the first trimester, and continue to rise until term. Contd …

46. After the 4 th month of pregnancy the bladder trigone (base of bladder) is lifted and there is thickening of its intraureteric margin owing to the enlarging uterus, hyperemia of all the pelvic organs and hyperplasia of the muscles and connective tissue. Bladder pressure increases and may result in reduced bladder capacity. Urinary bladder

47. The muscles of the internal sphincter relax which, along with pressure from the pregnant uterus on the bladder causes a significant number of women to experience some degree of stress incontinence Urgency of micturition and urge incontinence also increases in pregnancy, partly because of the effects of progesterone on the detrusor muscles. These all usually resolve during the puerperium . Contd …

48. Gastro intestinal system:

49. During pregnancy, nutritional requirements, including those for vitamins and minerals, are increased, and several maternal alterations occur to meet this demand. The mother`s appetite usually increases, so that food intake is greater. Some women have a decreased appetite or experience nausea and vomiting. These symptoms may be related to relative levels of human chorionic gonadotrophin ( hCG ). GI SYSTEM:

50. Salivation may seem to increase due to swallowing difficulty associated with nausea ,and if the pH of the oral cavity decreases, tooth decay may occur. Due to the effect of estrogen, gum becomes congested and spongy and may lead to bleed on touch and gingivitis. Oral cavity:

51. Transit time of food throughout the gastrointestinal tract may be so much slower that more water than normal is reabsorbed, leading to constipation. Gastric production of hydrochloric acid is variable and sometimes exaggerated, especially during the first trimester. More commonly, gastric acidity is reduced. Oral cavity condt …

52. Gastric production of mucus may be increased. Esophageal peristalses is decreased, accompanied by gastric reflux because of the slower emptying time and dilatation or relaxation of the cardiac sphincter. Gastric reflux is more prevalent in later pregnancy owing to elevation of the stomach by the enlarged uterus. Contd …

53. Gallbladder function is also altered during pregnancy because of the hypotonia of the smooth muscle wall. Emptying time is slowed and often incomplete. Bile can become thick, and bile stasis may lead to gallstone formation . Gallbladder :

54. There are no apparent morphologic changes in the liver during normal pregnancy, but there are functional alterations. Serum alkaline phosphatase activity can double, probably because of increased placental alkaline phosphatase isoenzymes . Thus, a decrease in the albumin/globulin ratio occurs normally in pregnancy . Liver:-

55. The female endocrine system consists of the pituitary, the pineal body, the thyroid, the adrenal and the thymus glands, along with the pancreas and the ovaries. All of them undergo changes during pregnancy in order to prepare the mother’s body to effectively meet the challenges associated with pregnancy, childbirth and breastfeeding Endocrine system:

56. Some of the most significant changes occur in the pituitary and thyroid glands to meet the nutritional needs of the baby in the uterus, restricting reproductive organs and passing on genetic information. Endocrine system

57. Morphological changes : During normal pregnancy,the pituitary increases in weight by 30-50% and is enlarged to about twice its normal due to the hyperplasia of acidophilic prolactin secreting cells. Physiological changes: P osterior pituitary: Near the end of term, the posterior pituitary will begin to secrete oxytocin that was produced in the hypothalamus and stored there. It will serve to initiate labor. Pituitary gland:

58. Anterior pituitary: At birth, the anterior pituitary will begin to secrete prolactin. It is increased 10 times. This stimulates the production of breast milk. Growth hormone level is elevated due to syncytiotrophoblast of the placenta. ADH and TSH remains unchanged. Cntd …

59. Morphological changes:Hyperplasia of the thyroid gland occurs and slight generalized enlargement of the gland, however pregnant women remain euthyroid . Physiological changes:- Maternal serum iodine levels fall due to increased renal loss and transplacental shift to the fetus. TSH remains normal.total T4 and T3 increases but free T4 and T3 levels remains unchanged. Calcitonin secretions increases by 20%. Thyroid gland:

60. M orphological changes: There is slight enlargement of the adrenal cortex. Physiological changes: There is significant increase in the serum levels of aldosterone, deoxycorticosterone (DOC), cortico steroid binding globulin (CBG),cortisol and free cortisol. The adrenal cortex:

61. M orphological changes: Parathyroid hyperplasia occur. Physiological changes: The concentration of PTH doesn’t change during pregnancy. PTH doesn’t cross the placenta but the calcium ions do cross along the concentration gradient. The parathyroid gland:

62. During pregnancy, there occur hyperinsulininsm particularly during third trimester but there are several anti-insulin factors and tissue insulin resistance which modify the action of insulin during pregnancy which results in gestational diabetes. Pancreas :

63. During these adaptations various changes occur that has impact on the skeletal system, which can develop variety of problems such as back pain, separation of the pelvic bones, transient osteoporosis, and tendonitis , strain in the axial skeleton and pelvis. Musculoskeletal system:

64. Exaggerated lordosis of the lower back, forward flexion of the neck, and downward movement of the shoulders typically occur to compensate for the enlarged uterus and change in center of gravity . There is widening and increased mobility of the sacroiliac joints and pubic symphysis in preparation for the fetus' passage through the birth canal.

65. In normal pregnancy, variable amount of weight gain is a constant phenomenon. Inearly 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. W eight gain:

66. The total weight gain at term is distributed approximately as follows: Reproductive weight gain: 6 kg Net maternal weight gain – 6kg Fetus – 3.3kg, placenta- 0.6kg and liquor-0.8kg.   Uterus : 0.9 kg and breast -0.4 kg .   Accumulation of fat and protein – 3.5 kg     Increased in blood volume- 1.3kg. Increased in extracellular fluid - 1.2kg.

67. Pigmentation : the distribution of pigmentary changes is selective. Face: its is an extreme form of pigmentation around the cheek, forehead and around the eyes. Abdomen: Linea nigra - brownish black pigmentation. Stria gravidum . Sweat glands will be active ,more body secreation . Cutaneous changes:

68. Compression of pelvic nerve or vascular stasis caused by enlargement of the uterus may result in sensory changes in the legs. Edema involving the peripheral nerve may result in carpal tunnel syndrome. Neurologic changes:

69. Forthcoming parenthood causes psychological changes in mother ,physical stress, hormonal changes, coping with changing body shape and yet going about in life and performing daily living attending to the need of the family and children all together may affect the emotional equilibrium of the would be mother . The formost psychological changes that can affect the pregnant lady are mood swings. Being angry and unreasonable , feeling good and depressed successively, being tensed and changing body shape and hormone level .   Psychological changes during pregnancy.

70. Some other psychological changes are: Mood swings. Moodiness irritability ,pregnancy can bring a roller roster of emotions. Fear. Forgetfulness. Weepiness.

71. Marshall, J & raynor , M.Myles textbook for midwives.17 th edi .(2014). churchill livingstone . Dutta , DC.textbook of obstetrics .9 th edi.new central book agency.pvt.ltd . REFERENCES: