VERY IMPORTANT TOPIC

1. ANATOMICAL CHANGES
IN PREGNANCY
MODERATOR:DR.GOVERDHAN.S
PRESENTER:DR.C.R.TEJASWINI

2. During pregnancy there is progessive anatomical,
physiological and biochemical change not only confined to
the genital organs but also to all systems of the body.
This is principally a phenomenon of maternal adaptation to
the increasing demands of the growing fetus. Unless well
understood, this physiological adaptations of normal
pregnancy can be misinterpreted as pathological.

3.  Many gestational changes begins soon after
fertilisation and continue throughout the
pregnancy.Equally astounding is that the
women is returned to her prepregnancy state
after delivery(6weeks) and lactation

4. 1.ANATOMICAL
2.PHYSIOLOGICAL
3.BIOCHEMICAL

5. Early signs of pregnancy
 Goodell sign : softening of cervix 1st sign – 6 weeks of
pregnancy
 Hegar sign :softening of the lower part of the uterus ,elicited
by bimanual examination . Seen at 6-10 weeks of pregnancy
 Osiander sign : pulsations in the lateral fornix of the vagina
 Piskacek sign :asymmetrical growth of uterus in early
pregnancy due to eccentric implantation
 Chadwick/jacquemier sign :bluish discolouration of vagina and
cervix during pregnancy

6. CHANGES IN
REPRODUCTIVE
ORGANS

7. VULVA:
Vulva becomes edematous and more
vascular; superficial varicosities may
appear specially in multiparae. Labia
minora are pigmented and
hypertrophied.

8. VAGINA
 Vaginal walls becomes hypertrophied, edematous and more vascular.
Increased blood supply of the venous plexus surrounding the walls
gives the bluish coloration of the mucosa (Jacquemier’s sign). The
length of the anterior vaginal wall is increased.
Secretion: The secretion becomes copious, thin and curdy white,
due to marked exfoliated cells and bacteria. The pH becomes acidic
(3.5–6) due to more conversion of glycogen into lactic acid by the
Lactobacillus acidophilus consequent on high estrogen level. The
acidic pH prevents multiplication of pathogenic organisms

9. .Cytology: There is preponderance of
navicular cells in cluster (small intermediate
cells with elongated nuclei) and plenty of
lactobacillus.
The vaginal wall undergoes striking changes
in preparation for the distension that
accompanies labour and delivery.these
alterations include considerable epithelium
thickening connective tissue loosening and
smooth muscle hypertrophy

10. UTERUS
The uterus expands from a pelvic organ
i.e before 12 weeks to become an
abdominal organ for the remaining of
gestation
The uterus increases in weight from 60
to 1000g

12. In length, it changes from 6.5 to 32cm
Its shape changes from
GLOBULAR
SPHERICAL(BY 12 WEEKS)
OVOID ( ABDOMINAL)

13. NON
PREGNANT
50-80 GM
7.5CMS
5-10 ML
PEAR SHAPED
PREGNANT
1000GM
35 CMS
5L
GLOBULAR
SPHERICAL
OVOID
WEIGHT
LENGTH
VOLUME
SHAPE

15. CHANGES IN ALL 3 PARTS OF
UTERUS
1.BODY
2.ISTHMUS
3.CERVIX

17. uterine expansion and increase in
weight of uterus
Growing fetus ↑ in connective
tissue
↑ Size and no.of .
Blood vessels
↑Hypertrophy and
hyperplasia of
muscle

18.  BODY OF THE UTERUS: There is increase in growth
and enlargement of the body of the uterus.
 Enlargement: The enlargement of the uterus is
affected by the following factors:• Changes in the
the muscles
 (1) Hypertrophy and hyperplasia: Not only the
individual muscle fiber increases in length and
breadth but there is limited addition of new muscle
fibers. These occur under the influence of the
hormones-estrogen and progesterone limited to
the first half of pregnancy but pronounced upto 12
weeks. (

19.  2) Stretching: The muscle fibers further elongate beyond 20 weeks due to
distension by the growing fetus. The wall becomes thinner and at term,
measures about 1.5 cm or less. The uterus feels soft and elastic in contrast to
firm feel of the nongravid uterus.
 Arrangement of the muscle fibers: Three distinct layers of muscle fibers are
evident:
 (1) Outer longitudinal—It follows a hood like arrangement over the fundus;
some fibers are continuous with the round ligaments.
 (2) Inner circular—It is scanty and have sphincter like arrangement around
the tubal orifices and internal os.
 (3) Intermediate—It is the thickest and strongest layer arranged in criss-
cross fashion through which the blood vessels run. Apposition of two double
curve muscle fibers give the figure of ‘8’ form. Thus, when the muscles
contract, they occlude the blood vessels running through the fibers and
hence called living ligature
 • There is simultaneous increase in number and size of the supporting
fibrous and elastic tissues.

21. Vascular system—
Whereas in the nonpregnant state, the blood supply to
the uterus is mainly through the uterine and least
through the ovarian but in the pregnant state, the latter
carries as much the blood as the former.
There is marked spiralling of the arteries, reaching the
maximum at 20 weeks; thereafter, they straighten out.

22. Doppler velocimetry has shown uterine artery
diameter becomes double and blood flow
increases by eight fold at 20 weeks of
pregnancy.
 This vasodilatation is mainly due to estradiol
and progesterone. Veins become dilated and
are valveless. Numerous lymphatic channels
open up. The vascular changes are most
pronounced at the placental site.

23.  Position: Normal anteverted position is exaggerated upto 8
weeks. Thus, the enlarged uterus may lie on the bladder
rendering it incapable of filling, clinically evident by frequency
of micturition.
Afterwards, it becomes erect, the long axis of
the uterus conforms more or less to the axis of the inlet.
As the term approaches, specially in multiparae with lax
abdominal wall, there is a tendency of anteversion. But in
primigravidae with good tone of the abdominal muscles, it is
held firmly against the maternal spine.

24.  Lateral obliquity: As the uterus enlarges to occupy
the abdominal cavity, it usually rotates on its long
axis to the right (dextrorotation).
This is due to the occupation of the rectosigmoid
in the left posterior quadrant of the pelvis.
This makes the anterior surface of the uterus to turn
to the right and brings the left cornu closer to the
abdominal wall. The cervix, as a result, is deviated to
the left side (levorotation) bringing it closer to the
ureter.

25.  Uterine peritoneum: The peritoneum maintains the
relation proportionately with the growing uterus.
The uterosacral ligaments and the bases of the
broad ligament rise upto the level of the pelvic
brim.
 This results in deepening of the pouch of Douglas.
Large areas of the lower lateral walls of the uterus
remains uncovered by peritoneum. These places are
filled up by loose and vascular connective tissues.

26. Afterwards, it becomes erect, the long axis of the
uterus conforms more or less to the axis of the inlet.
approaches, specially in multiparae with lax
abdominal wall, there is a tendency of anteversion.
But in primigravidae with good tone of the abdominal
muscles, it is held firmly against the maternal spine.

27. Contractions (Braxton-Hicks)
Uterine contraction in pregnancy has been named after Braxton-
Hicks who first described its entity during pregnancy.
From the very early weeks of pregnancy, the uterus undergoes
spontaneous contraction. This can be felt during bimanual
palpation in early weeks or during abdominal palpation when the
uterus feels firmer at one moment and soft at another.
Although spontaneous, the contractions may be excited by
rubbing the uterus. The contractions are irregular, infrequent,
spasmodic and painless without any effect on dilatation of the
cervix.

28.  The patient is not conscious about the contractions.
 Near term, the contractions become frequent with
increase in intensity so as to produce some discomfort
to the patient. Ultimately, it merges with the painful
uterine contractions of labor. In abdominal pregnancy,
Braxton-Hicks contraction is not felt.

29. During contraction
there is complete closure of the uterine veins with partial
occlusion of the arteries in relation to intervillous space resulting
in stagnation of blood in the space. This diminishes the placental
perfusion, causing transient fetal hypoxia which leads to fetal
bradycardia coinciding with the contraction

30.  Endometrium : The decidua is the endometrium of
the pregnant uterus. It is so named because much
of it is shed following delivery.
 Decidual reaction : The increased structural and
secretory activity of the endometrium that is
brought about in response to progesterone
following implantation is known as decidual
reaction.

31.  The well developed decidua differentiates into three layers
 (1) Superficial compact layer consists of compact mass of decidual
cells, gland ducts and dilated capillaries. The greater part of the
surface epithelium is either thinned out or lost.
 (2) Intermediate spongy layer (cavernous layer) contains dilated
uterine glands, decidual cells and blood vessels. It is through this
layer that the cleavage of placental separation occurs.
 (3) Thin basal layer containing the basal portion of the glands and is
apposed to the uterine muscle. Regeneration of the mucous coat
occurs from this layer following parturition

32.  After the interstitial implantation of the blastocyst into the compact
layer of the decidua, the different portions of the decidua are
renamed as
 (1)Decidua basalis or serotina — the portion of the decidua in
contact with the base of the blastocyst
 (2) Decidua capsularis or reflexa — the thin superficial compact
layer covering the blastocyst
 (3) Decidua vera or parietalis — the rest of the decidua lining the
uterine cavity outside the site of implantation. Its thickness
progressively increases to maximum of 5–10 mm at the end of the
second month and thereafter regression occurs with advancing
pregnancy so that beyond 20th week, it measures not more than 1
mm.

35. ISTHMUS
There are important structural and functional changes in the isthmus during pregnancy.
During the first trimester, isthmus hypertrophies and elongates to about 3 times its
original length. It becomes softer. With advancing pregnancy beyond 12 weeks, it
progressively unfolds from above, downwards until it is incorporated into the uterine
cavity.
The circularly arranged muscle fibers in the region function as a sphincter in early
pregnancy and thus help to retain the fetus within the uterus. Incompetency of the
sphincteric action leads to mid-trimester abortion and the encirclage operation done to
rectify the defect is based on the principle of restoration of the retentive function of the
isthmus

38. CERVIX
Stroma: There is hypertrophy and hyperplasia of the elastic and
connective tissues. Fluids accumulate inside and in between the fibers.
Vascularity is increased specially beneath the squamous epithelium of
the portio vaginalis which is responsible for its bluish coloration.
There is marked hypertrophy and hyperplasia of the glands which
occupy about half the bulk of the cervix. All these lead to marked
softening of the cervix (Goodell’s sign) which is evident as early as 6
weeks.
It begins at the margin of the external os and then spreads upwards. It
not only provides diagnostic aid in pregnancy but the changes in the
cervix facilitate its dilatation during labor.

39. Epithelium: There is marked proliferation of the endocervical
mucosa with downward extension beyond the squamocolumnar
Junction
 .This gives rise to clinical appearance of ectopy (erosion)
cervix. Sometimes, the squamous cells also become
hyperactive and the mucosal changes simulate basal cell
hyperplasia or cervical intraepithelial neoplasia (CIN).
 These changes are hormone induced (estrogen) and regress
spontaneously after delivery.

40.  Secretion:
The secretion is copious and tenacious-physiological
leucorrhea of pregnancy. This is due to the effect of
progesterone. This mucous is rich in immunoglobulins and
cytokines. The mucus not only fills up the glands but forms a
thick plug effectively sealing the cervical canal. Microscopic
examination shows fragmentation or crystallization (beading)
due to progesterone effect.

41.  Anatomical:
 The length of the cervix remains unaltered but becomes bulky.
The cervix is directed posteriorly but after the engagement of
the head, directed in line of vagina. There is no alteration in the
relation of the cervix. There is unfolding of the isthmus;
beginning 12 weeks onwards and takes part in the formation of
the lower uterine segment. Variable amount of effacement is
noticed near term in primigravidae. In multiparae, the canal is
slighly dilated.

43. Fallopian tube
 As the uterine end rises up and the fimbrial end is
held up by the infundibulo-pelvic ligament, 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 one-third, because of marked
growth of the fundus. The total lengthis somewhat
increased. The tube becomes congested. Muscles
undergo hypertrophy. Epithelium becomes flattened
and patches of decidual reaction are observed.

44. OVARY:
 The growth and function of the corpus luteum reaches its maximum at 8th
week when it measures about 2.5 cm and becomes cystic.
 It 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.
 Colloid degeneration occurs at 12th week which later becomes calcified at
term. Hormones-estrogen and progesterone secreted by the corpus luteum
maintain the environment for the growing ovum before the action is taken
over by the placenta.

45.  These hormones not only control the formation and
maintenance of decidua of pregnancy, but also inhibit
ripening of the follicles.
 Thus both the ovarian and uterine cycles of the normal
menstruation remain suspended. Luteoma of pregnancy
results from exaggerated, luteinization reaction of the
ovary.

46. BREAST
 The changes in the breasts are best evident in a
primigravida. In multipara who has once lactated, the
changes are not clearly defined.
 SIZE: Increased size of the breasts becomes evident even in
early weeks. This is due to marked hypertrophy and
proliferation of the ducts (estrogen) and the alveoli
(estrogen and progesterone) which are marked in the
peripheral lobules.

47.  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. Quite often, the “axillary tail”
(prolongation of the breast tissue under cover of the
pectoralis major) becomes enlarged and painful. There may
be evidence of striation due to stretching of the cutis.

48.  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.

51.  SECRETION: Secretion (colostrum) can be squeezed out of
the breast at about 12th week which at first becomes sticky.
Later on, by 16th week, it becomes thick and yellowish.
 The demonstration of secretion from the breast of a woman
who has never lactated is an important sign of pregnancy.
In latter months, colostrum may be expressed from the
nipples. For normal changes and lactation

52. CUTANEOUS CHANGES
 PIGMENTATION: The distribution of pigmentary
changes is selective.
 1. 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.
 2. Breast: The changes are already described (vide
supra).

54. Abdomen:
 Linea nigra: It is a brownish black pigmented area in the
midline stretching from the xiphisternum to the symphysis
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
as similar changes are observed in women taking oral
contraceptives. The pigmentation disappears after
delivery.

56. Striae gravidarum:
These are slightly depressed linear marks with varying
length and breadth found in pregnancy. They are
predominantly found in the abdominal wall below the
umbilicus, sometimes over the thighs and breasts.
These stretch marks represent the scar tissues in the
deeper layer of the cutis. Initially, these are pinkish but
after the delivery, the scar tissues contract and
obliterate the capillaries and they become glistening
white in appearance and are called striae albicans.

57.  Apart from the mechanical stretching of the skin,
increase in aldosterone production during
pregnancy are the responsible factors.
 Controlled weight gain during pregnancy and
massaging the abdominal wall by lubricants like
olive oil may be helpful in reducing their formation.
Apart from pregnancy, it may form in cases of
generalized edema, marked obesity or in Cushing’s
syndrome

58. OTHER CUTANEOUS CHANGES
 These include vascular spider and palmar
erythema which are due to high estrogen level.
level. Mild degrees of hirsutism may be
observed and in puerperium the excess hair is
lost.

59. WEIGHT GAIN
 In normal pregnancy, variable amount of weight gain is a
constant phenomenon. 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. The total weight gain at term
is distributed approximately as follows

61. Importanceof weight checking
 Single weight checking is of little value except to identify the
overweight or underweight patient. Periodic and regular
weight checking is of importance to detect abnormality.
 Rapid gain in weight of more than 0.5 kg (1 lb) a week or
more than 2 kg (5 lb) a month in later monthsof pregnancy
may be the early manifestation of pre-eclampsia and need
for careful supervision.
 Stationary or falling weight may suggest intrauterine growth
retardation or intrauterine death of fetus.

62.  During pregnancy, there is variable amount of retention of
electrolytes—sodium (1000 mEq), potassium (10 g) and
chlorides.
 The sodium is osmotically active and partially controls the
distribution of water in various compartments of the body.
Causes of increased sodium retention during pregnancy
are:
 (1) increased estrogen and progesterone
 (2) increased aldosterone consequent on the activation of
the renin-angiotensin system and possibly
 (3) due to increased antidiuretic hormone. The amount of
water retained during pregnancy at term is estimated to be
6.5 liters.

63.  The increased accumulation of fluid in the tissue
spaces mainly below the uterus is due to
(1) diminished colloid osmotic tension due to
hemodilution driving the fluid out of the vessels
(2) increased venous pressure of the inferior
extremities. Thus, slight edema of the legs is not
uncommon, in otherwise normal pregnancy.

64.  Ideally weight gain should depend on pre-
pregnancy body mass index (BMI) level
 Weight gain for a woman with normal BMI (20–26)
is 11–16 kg.
 An obese woman (BMI > 29) should not gain more
than 7 kg. whereas an under weight woman (BMI <
19) may be allowed to gain upto 18 kg.
 Maternal nutrition and weight gain during
pregnancy is directly related to the newborn weight.
However, it may not be a specific indicator as there
are other factors for low birth weight infant

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