2. Introduction
❖ Occur in response to physiological stimuli provided
by the fetus or placenta
❖ Most return to her pre pregnancy state after
delivery and lactation
❖ Can be misinterpreted as pathological but can
unmask or worsen preexisting disease
❖ Every organ system undergoes anatomical and
functional change
❖ The aim is to maximize nutrition and oxygen to
the developing fetus and help the maternal system
adjust to the extra stress.
2
3. Regulation
By the feto-placental unit through hormones produced
by the placenta and the fetal adrenals.
❖
Estrogen
❖
Progesterone
❖
Human placental lactogen
❖
Growth hormone
❖
Cortisol
❖
Mellanocyte stimulating hormone
4. Hormone Physiological action in pregnancy
Estrogen Uterine growth; Breast growth; liver enzyme changes; increased
peripheral insulin resistance; increased proliferation of blood vessels in
uterus; hematopoiesis
Progesterone Uterine smooth muscle relaxation; peripheral arteriolar and other blood
vessels relaxation; Increased peripheral blood flow due to vascular
relaxation; increased respiratory rate due to effect on respiratory center
Human
placental
lactogen
Increased peripheral insulin resistance; Increased lipolysis and ketone
body production
Growth
hormone
Increased peripheral insulin resistance
Cortisol Fluid and electrolyte retention leading to increased total body water and
electrolytes; Increased insulin resistance
Mellanocyte
stimulating
hormone
Dark coloration of the breast, areola, linea nigra
5. Knowledge about…
Helps in
❖ understanding normal laboratory measurements,
❖ knowing the drugs likely to require dose
adjustments, and
❖ recognizing women who are predisposed to
medical complications during pregnancy.
7. Systemic changes
❖ Weight
❖ Abdominal wall
❖ Skin & mucous
membranes
❖ Breasts
❖ Hematologic changes
❖ Circulatory system
❖ Respiratory system
❖ Urinary system
❖ Alimentary system
❖ Endocrine system
❖ Musculoskeletal
system
❖ Immune system
7
8. Local changes
◼ Uterus
❑ in size in a few months and then to return
essentially to its original state within a very few
weeks
❑ In the non-pregnant woman weighing about 70 g
≈1-1.1kg
❑ Cavity of 10 mL or less-- at terms averages 5 l
❑ Size 5-6 times: from 7x5x3cm35x25x22cm
8
9. Cont’d
◼ Position:
❑ It changes as pregnancy advances ( pearl-spherical-
ovoid)
❑ Early an exaggerated anteflexion
❑ 12th week rises from the pelvis and contacts the
anterior abdominal wall
❑ Rotates somewhat to the right
❑ In supine, the uterus falls back to rest on the
vertebral column and the adjacent great vessels
9
10. Cont’d
• The initial stimulus to uterine hypertrophy is
hormonal (estrogen and progesterone )—up to 6 wks
• After 12 weeks, the increase of the uterus is due to
the effect of pressure exerted by the expanding
products of conception
• Uterine enlargement is most marked in the fundus
10
11. Cont’d
Contractility
• From the 1st trimester onward, the uterus undergoes
irregular contractions, which normally are painless
• They can be detected by abdominal examination after 2nd
trimester
• Until the last month of gestation they are infrequent, but
increase in frequency during the last week or two
• Late in pregnancy, these contractions may cause some
discomfort and account for so-called false labor
11
12. Lower uterine segment
◼ From the beginning of the 2nd trimester until the last
few weeks of pregnancy the isthmic portion
hypertrophies and becomes indistinguishable from
the rest of the uterine muscle
◼ Late in pregnancy and most particularly during labor
the lower uterine segment becomes thinned out
12
13. Uteroplacental blood flow
◼ The uterine blood flow in normal term pregnancy
averages 450 to 650 mL/min ( 50 ml/min in the non
pregnant state)
◼ Increase in maternal-placental blood flow during
gestation occurs principally by means of
vasodilatation
13
14. Cervix
◼ Pronounced softening and cyanosis of the cervix
occurs as early as 1 month after conception
◼ These changes are apparent 5th-6th week
◼ By the end of pregnancy glands occupy half of the
entire cervical amass
◼ Normal pregnancy-induced changes represent an
extension, or eversion, of the proliferating
columnar endocervical glands
14
16. Ovaries
❖ Maturation of new follicles is suspended
❖ Only a single corpus luteum can be found and
function as source of progesterone
❖ First 6 to 7 weeks of pregnancy
❖ Ovarian vascular pedicle increased during
pregnancy from 0.9 cm to approximately 2.6 cm at
term
16
17. Fallopian Tubes
◼ Musculature of the fallopian tubes undergoes little
hypertrophy during pregnancy
◼ Epithelium of the tubal mucosa becomes somewhat
flattened
17
18. Vagina
◼ Becomes deeply congested and cyanotic
◼ In preparation for the distension that occurs in labor:
➢ Mucosa thickens
➢ Connective tissue becomes less dense
➢ Muscular coat hypertrophies
18
19. vulva
◼ vascularity & hyperemia develops in the skin and
muscles of the perineum and vulva
◼ There is softening of the normally abundant
connective tissue of these structures
19
20. Systemic Changes
◼ Metabolic changes
❑ Maternal basal metabolic rate is increased by 10
to 20 percent
❑ Increased by an additional 10 percent in women
with twin gestations
◼ Weight
❑ Hormonal changes are responsible for a
considerable in weight during pregnancy
❑ Women gain an average of approximately 12.5
kg, and it may be approximated as follows
20
22. Abdominal wall, skin & mucous membranes
Striae Gravidarum (“stretch marks”)
▪ Pink to purple, linear patches located on the
abdomen, breasts, buttocks and thighs
▪ Show dermal and epidermal atrophy
▪ Seen in 50% of pregnant women
▪ Related with the effect of adrenocortical
hyperactivity
▪ After delivery discoloration gradually fades
22
24. Cont’d
◼ Hyper pigmentation
❑ Develops in up to 90 % of women
❑ linea nigra; Darkening of lower midline of the
abdomen from the umbilicus to the pubis
❑ Cloasma or mask of pregnancy
24
26. Breasts
◼ Start enlarging since 8th week of pregnancy
◼ Delicate veins become visible beneath the skin
◼ Nipples become
❑ in size
❑ Deeply pigmented
❑ Erectile
◼ The primary areola deepens in color and secondary
areola develops at periphery
26
27. HEMATOLOGIC CHANGES
◼ Blood volume
❑ Retention of sodium and water has important
hemodynamic consequences
❑ 40–45% above non pregnant levels after 32-34
wks
❑ Expands most rapidly during second trimester
❑ Results from an increase in both plasma and
erythrocytes
27
28. Cont’d
◼ Total red cell volume
❑ Begins to rise at 10 wks rises until term
❑ Average 450 ml (increase by 33%)
◼ Plasma >RBC
❑ Hemodilution
❑ Physiologic anemia of pregnancy
28
30. Cont’d
❑ Advantage of increase in blood volume
➢ Protects mother from possibility of haemorrhage
➢ Helps fill the expanded vascular system created by
◼ vasodilatation
◼ low -resistance vascular pool with in the
uteroplacental unit
➢ Protect the mother and fetus against the deleterious
effects of impaired Venous Return in the supine and
erect position
➢ To provide an abundance of nutrients and elements
to support the rapidly growing placenta and fetus
30
31. Cont’d
Hemoglobin Concentration and Hematocrit
❑ Hemoglobin concentration at term averages 12.5
g/dL
◼ <11 g/dl abnormal in late gestation
❑ Iron requirements
✓ In normal pregnancy 1 g
✓ 200 mg is excreted
✓ 300 mg is transferred to fetus
✓ 500 mg is needed for the mother
✓ Daily average requerement is 6-7 mg/day
31
32. CIRCULATORY SYSTEM
◼ Heart
❑ Position and size-- little and pushed by the
elevation of the diaphragm
❑ Heart rate-- about 10-15 beats/min
❑ Heart sounds
◼ 1st and 3rd sounds become louder.
◼ Systolic ejection murmurs develop in most of
the women
❑ EKG --slight deviation of the electrical axis of
the left 32
34. Cont’d
◼ Cardiac output
❑ Begins to 5th week 40% 20-24 weeks
❑ Fluctuates markedly with changes in body position
◼ lowest in sitting or supine position
◼ highest in Rt and Lt lateral and knee chest
position
34
35. Blood pressure
❑ during 2nd TM (nadir at 24 to 26 weeks)
❑ Supine position-femoral venous pressure rises
◼ Stagnation in the lower extremities
◼ Dependent edema
◼ Systemic vascular resistance decrease
❑ Smooth muscle relaxing effect of progesterone
❑ Presence of a vasodilator on artery and vein
(NO,PG)
35
36. Cont’d
◼ Supine Hypotension
❑ 10 % of women
❑ Compression effect of gravid uterus
❑ Can occurs with hemorrhage or spinal analgesia
❑ Relieved by
❑ Left lateral position
❑ Placing a wedge under the woman's right side
❑ Adjusting the operating table to a 30º left lateral
tilt
36
38. RESPIRATORY SYSTEM
◼ Alterations are largely due to anatomical changes
❑ Diaphragm rises about 4 cm
❑ Sub costal angle widens
❑ Transverse diameter of thoracic cage increases
about 2 cm
❑ Circumference of the thoracic cage increases about
6 cm
38
39. Cont’d
◼ Respiratory rate is essentially unchanged,
◼ Tidal volume and resting minute ventilation increase
significantly as pregnancy advance
◼ Increase in minute ventilation is
❑ Due to the stimulatory effects of progesterone
❑ Low expiratory reserve volume, and
❑ Compensated respiratory alkalosis
◼ Functional residual capacity and the residual volume
are decrease
❑ Consequence of the elevated diaphragm
39
42. URINARY SYSTEM
◼ Kidneys
❑ Size ↑ because ↑ vasculature & Interstitial
volume
◼ Ureters
❑ Dilatation of the calyces, renal pelvis and ureters
◼ Prominent on the right side
◼ Seen as early as the 1st TM
◼ Present in 90% of women by the 3rd trimester
❑ Smooth Muscle relaxation by progesterone 42
43. Cont’d
◼ Urinalysis
❑ Glucosuria during pregnancy may not be abnormal
due to impaired tubular reabsorptive capacity for
filtered glucose
❑ Proteinuria normally is not evident during
pregnancy except occasionally in slight amounts
during or soon after vigorous labor
❑ Hematuria is often the result of contamination
during collection .If not, suggests urinary tract
disease
43
44. Gastrointestinal system
• Gums are often swollen and bleed easily
• Ptyalism can be found, almost always associated
with nausea
• Heartburn because of reflux oesophagitis resulting
from regurgitation of gastric acid
• No increase in liver size during human pregnancy
• Total alkaline phosphatase activity almost doubles
(placental alkaline phosphatase isozymes).
44
46. Cont’d
◼ Gastric tone, secreting activity, and motility are
◼ Relaxation of smooth muscle of colon
❑ Constipation is a common complaint
◼ Hemorrhoids are common
◼ Gallbladder is distended and hypotonic
❑ Bile is quite thick.
❑ Predisposes to formation of gallstones
46
47. ENDOCRINE SYSTEM
◼ Pituitary
❑ Enlarges by 135% -proliferation of prolactin
producing cells in the anterior pituitary
◼ Thyroid gland
❑ Thyroid stimulating factors of placental origin
are produced e.g. hcG
❑ Decreased availability of iodide for maternal
thyroid
◼ Increase renal loss of iodide
◼ Transfer of iodide to the foetus
47
48. Adrenal gland
◼ There is a steady in total plasma cortisol
◼ Plasma levels of adrenaline and noradrenalin are the
same as in the non pregnant state
48
49. MUSCULOSKELETAL SYSTEM
◼ Progressive lordosis
◼ mobility of the sacroiliac, sacrococcygeal & the
pubic joints
◼ During the last trimester: aching, numbness, and
weakness in the upper extremities
49
50. summary
o Pregnancy is not a disease
o Profound changes in physiology and anatomy
o Affects most organ systems
o Can dramatically impact disease states,
susceptibility, and treatment
o Almost all of us will encounter and treat pregnant
women
o Even if you don’t know it
o Under-appreciation of changes will lead to
suboptimal treatment or outright mistakes
50
