Physiological changes in pregnancy affect many body systems. The reproductive tract undergoes changes like increased vascularity in the vulva, vagina and cervix to accommodate birth. The breasts enlarge due to ductal and alveolar growth in preparation for lactation. Metabolic changes increase calorie and protein needs to support the growing fetus. The uterus expands dramatically under the influence of hormones to carry the pregnancy.

1. PHYSIOLOGICAL
CHANGES IN
PREGNANCY: PART -
1
PRESENTER – DR. KAJAL GUPTA
MODERATOR – DR. MAYURI AHUJA

2. INTRODUCTION
Physiological changes begin soon after fertilisation and continues throughout pregnancy.
Following changes will be discussed:
Reproductive tract
Breast
Skin
Metabolic changes

3. VULVA AND VAGINA
 increase in vascularity and hyperaemia in the skin and
muscles of the perineum and vulva
 Increased vascularity leads to violet discolouration of vagina
and cervix
 epithelial thickening, connective tissue loosening, and
smooth muscle cell hypertrophy.
 all women show greater hiatal distensibility of vagina to
facilitate delivery.

4. • Vaginal ph decreases during pregnancy (~3.5)
• due to increase doderlline bacteria more glycogen is
converted into lactic acid .

5. CERVIX
 About 1 month after
conception, the cervix begins to
soften and had bluish tone.
 increase vascularity edema and
collagen change
 hypertrophy and hyperplasia of
the cervical glands

6.  Rearrangement of collagen-rich tissue aids the cervix in retention
of the pregnancy and dilatation.
 Endocervical mucosal cells produce copious amounts of tenacious
mucus
 It obstruct the cervical canal to protect the uterine contents
against infection
 At labour onset, , this mucus plug is expelled, resulting in a bloody
show
CERVIX

7. SIGNS IN PREGNANCY
Chadwick’s Sign
A dark blue to purple –red congested
appearance of vaginal and cervical
mucosa
Hegar’s Sign
Occurs in first trimester
Softening of uterus at isthmus
Goodell’s sign
Softening of uterus after 6 weeks

9. CERVICAL RIPENING
 connective tissue remodelling
 lowers collagen and proteoglycan concentrations
raises water content
 result of progesterone

10. UTERUS
UTERINE ENLARGEMENT
 stretching ,hypertrophy and hyperplasia of muscle cells
 stimulated by estrogen and progesterone
it occurs maximum in fundus
Fibrous tissue accumulates
• MYOMETRIUM
muscle layer of uterus thicken and strengthen during first half of pregnancy
 Gradually becomes thin in second half.
By term, the myometrium is only 1 to 2cm thin.

11. UTERUS
NON PREGNANT
UTERUS
PREGNANT UTERUS
Muscular structure Almost solid Relatively thin walled
weight Approx. 70 grams Approx. 1100 grams at term
volume ≤ 10ml 5L at term (avg)

12. • By the end of 12 weeks, the enlarged
uterus extends out of the pelvis.
• It gradually increases in size reaching
xiphi-sternum at 38 weeks
• The longitudinal axis of the uterus
corresponds to the pelvic inlet axis.

13. BRAXTON HICKS CONTRACTIONS
 In second trimester, can be
detected by bimanual examination
 unpredictable and sporadic and
usually nonrhythmic
 may cause some discomfort and
account for false labour.
 Intrauterine pressure : 5-25mm of
Hg.

15. UTEROPLACENTAL BLOOD FLOW
• Placental perfusion depends on total uterine
blood flow (uterine, ovarian and collateral)
• Uteroplacental blood flow increase
progressively
• Approx. 450 mL/min in the mid trimester
• Nearly 500 to 750 mL/min at 36 weeks.
• Fall in vascular resistance accelerates the
flow velocity
• Shear stress in vessels lead to
circumferential vessel growth.
• Nitric oxide—a potent vasodilator has role

16. OVARIES AND FALLOPIAN TUBE
 Ovulation ceases during pregnancy
 maturation of new follicles is suspended.
 corpus luteum functions during the first 6 to 7 weeks of pregnancy
 diameter of the ovarian vascular pedicle increased from 0.9 cm to
approx. 2.6 cm at term..
 The fallopian tube musculature, myosalpinx, undergoes little
hypertrophy

17. BREAST
 Breast become tender in early pregnancy.
 From second month, the breasts grow in size.
 Colostrum- can be seen as early as 12weeks of pregnancy
 Colostrum is deficient in potassium, fat and carbohydrate.
 Colostrum is rich in immunoglobulin and vitamins.

18.  Hypertrophy and proliferation of
ducts due to estrogen
 increaseda lveoli due to estrogen
and progesterone.
 Hypertrophy of connective tissue
 Increased ducts due to effect of
estrogen.

19.  The nipples become
considerably larger, more
deeply pigmented
 Areolae become broader and
more deeply pigmented and
more erectile

20.  Scattered through areola, the
glands of Montgomery
 Hypertrophic sebaceous glands.
 Enlargement of these called
Montgomery tubercle

21. SKIN CHANGES
 STRIAE GRAVIDARUM
In mid pregnancy, reddish, slightly depressed streaks develop in the
abdominal skin and in the skin over the breasts and thighs.
 STRIAE ALBICANS
In multiparas, glistening, silvery lines ,representing previous stretch
marks.

22. .

23.  LINEA NIGRA
In the midline of the anterior
abdominal wall
Dark brown-black pigmentation the
Due to increased melanocyte
secreting hormone.

24.  Brownish patches of varying size appear on the face and neck,
giving rise to chloasma or melasma gravidarum—the mask of
pregnancy.
 Angiomas / vascular spiders, common on the face, neck, upper
chest, and arms.
 Minute, red skin papules with radicles branching out from a central
lesion.
 All the skin changes are due to increased estrogen except increase
basal body temperature which is due to progesterone.

26. METABOLIC CHANGES
Basal Metabolic Rate
 Increases by 20% by third trimester
30% in twins
 Total energy demand associated in pregnancy is 77000 kcal
 85, 285, and 475 kcal/d during the first, second, and third trimester,
respectively

27. • Pregnancy is an anabolic state.
• Total serum calcium decreases
• Foetus is dependent on mother for: glucose, thyroxine,
calcium
• Vit. D requirement during pregnancy: 10mcg(400IU)/day
• Calcium requirement in pregnancy: 1200mcg/day

29. WEIGHT GAIN
 weight gain of approx. 12.5 kg
mainly by -
 uterus and its contents
 breasts
 expanded blood and extravascular extracellular fluid
volumes.
 smaller fraction from accumulation of cellular water, fat, and
protein.

31. PROTEIN METABOLISM
• The products of conception, uterus and maternal blood are relatively
rich in protein
• placenta concentrates amino acids into the fetal circulation by facilitated
transport
• placenta also involved in protein synthesis, oxidation, and
transamination of some nonessential amino acids
• average requirements
• 1.22 g/kg/d of protein for early pregnancy
• 1.52 g/kg/d for late pregnancy.

32. WATER RETENTION
 Due to reset in osmotic threshold for thirst
 Vasopressin secretion
 Drop in plasma osmolarity of 10 mosm/kg.
 The amount of extra water that gets accumulated during
pregnancy (approx. 6.5 L)

33. CARBOHYDRATE
 mild fasting hypoglycaemia, postprandial hyperglycaemia, and hyperinsulinemia .
 peripheral insulin resistance, for supply of glucose to the fetus.
 insulin sensitivity in late normal pregnancy is 30 to 70 percent lower
 Insulin resistance is maximum between 24 to 28 weeks
 hormones such as progesterone, placentally derived growth hormone, prolactin,
human placental lactogen (HPL) and cortisol has role in this.
 Hepatic gluconeogenesis is augmented.
 Plasma concentrations of free fatty acids, triglycerides, and cholesterol are also
higher in the fasting state.

34. LIPID
 there is increase levels of lipid , lipoproteins and apolipoprotein in plasma
 increase insulin resistance due to estrogen.
 Triacylglycerol and cholesterol levels in very low-density lipoproteins (VLDLs),
low-density lipoproteins (LDLs), and high-density lipoproteins (HDLs) are
increased during the third trimester

35. ELECTROLYTES
 During normal pregnancy
1000 mEq of sodium
300 mEq of potassium
(nearly retained)
 serum concentrations are diminished slightly ( expanded plasma volume)
 Magnesium
both total and ionized magnesium concentrations are significantly lower
during normal pregnancy.

36. CALCIUM
 Total serum calcium levels, decrease during pregnancy.
 Serum ionized calcium level remains unchanged
 the fetal skeleton needs approximately 30 g of calcium (80% is
deposited in third trimester)
 demand is largely met by a doubling of maternal intestinal calcium
absorption mediated partly by 1,25-dihydroxyvitamin D3 and
adequate dietary intake.

37. IODINE
 Requirements increase during normal pregnancy
1.Greater thyroid hormone production for maternal euthyroidism
2.Transfer thyroid hormone to the fetus
3.Fetal iodine requirements , fetal thyroid hormone production
augmented renal clearance of iodine
4.Glomerular filtration rate increases by 30 to 50 percent.