ANATOMICAL AND
PHYSIOLOGICAL CHANGES PHYSIOLOGICAL CHANGES
DURING PREGNANCY
O BJECTIVES O BJECTIVES
At the end of the lecture, the student will be able to explain changes during pregnancy
di
regarding:
| Reproductive organs.
| Respiratory system
| Respiratory system.
| Endocrine system.
| Musculo-skeletal system.y
| Cutaneous system.
| Maternal weight.
| Nervous system.
Reproductive organs I Uterus:
I. Uterus:
| It increases in weight from 50 to 1000 gm. In size, it changes from 6.5 to 32 cm.
size, it changes from 6.5 to 32 cm.
| In the non- pregnant state, the uterus isp g , situated in the pelvic cavity. During pregnancy, it expands into the abdominal cavity. This is caused by: The growing fetus increased caused by: The growing fetus, increased connective tissues and size and number of blood vessels supplying the uterus.pp y g
Uterine positional changes during
pregnancy
|
Cervix
During pregnancy, it is closed. A mucus plug forms over the cervix, providing a protective barrier between the vagina and
th t i t t
the uterine contents.
|
Ligamentous supports
During pregnancy, they become elongated and hypertrophied They elongated and hypertrophied. They support and control the uterus in its movement from the pelvic cavity into thep y abdominal cavity.
RESPIRATORY SYSTEM
Ph i l i ll d i h b d
| Physiologically, during pregnancy, the body is in a state of hyperventilation due to high level of progesterone
level of progesterone.
| Breathing becomes more costal than
| Breathing becomes more costal than abdominal. Additionally, most women are mouth-breathers.
mouth breathers.
|
Anatomically, the diaphragm is
progressively elevated because of
progressively elevated because of
expansion and elevation of the rib
cage. Uterine pressure during the
cage. Uterine pressure during the
first and second trimesters does not
appear to be a factor in this
appear to be a factor in this
phenomenon.
METABOLIC AND ENDOCRINE CHANGES
1 Increase of endocrine hormones 1. Increase of endocrine hormones
A. Relaxin is a hormone secreted by the corpus luteum which is the endocrine body located in the ovary.
¾ It softens the connective tissue during pregnancy in preparation for labor when the pelvis must in preparation for labor when the pelvis must open to allow the fetal birth. Joints other than pelvis can also be affected.
¾ Relaxin peaks in early and late pregnancy.
Women with chronic joint instability may notice Women with chronic joint instability may notice an increase in symptoms during these times.
¾ It may be increased in the non-pregnant
¾ It may be increased in the non pregnant women after ovulation and throughout the menstrual period. This may cause softening
f h j i d i of the joints and pain.
B Oth j h i d i B. Other major hormones increase during pregnancy including estrogen, progesterone and placental lactogen.p g
Progesterone is sometimes called the
"hormone of pregnancy" and it has many roles relating to the development of the roles relating to the development of the fetus:
| It converts the endometrium to its secretoryy stage to prepare the uterus for implantation.
| At the same time, it affects the vaginal
ith li d i l ki it
epithelium and cervical mucus, making it thick. If pregnancy does not occur, progesterone levels decreases leading to progesterone levels decreases, leading to menstruation.
| During implantation and gestation, progesterone appears to decrease the maternal immune response to allow for the acceptance of the pregnancy
the pregnancy.
| In addition, it inhibits lactation during. The fall
| In addition, it inhibits lactation during. The fall in progesterone levels following delivery is one of the triggers for milk production.
2. Edema which is present in the hands, feet face and eyelids This is due to both feet, face and eyelids. This is due to both sodium and water retention and circulating hormones by the placenta,g y p , ovaries, and adrenal cortex that cause increased capillary permeability.
MUSCULOSKELETAL SYSTEM
Abd i l l t t h t th i t f th i
| Abdominal muscles stretch to the point of their elastic limit by the end of pregnancy.
| Hormonal influence on the ligaments produces systemic decrease in ligamentus tensile strength
d i i bilit f t t t d
and an increase in mobility of structures supported by those ligaments and may predispose the woman to joint injury especially in thej j y p y weight-bearingg g joints of the back, pelvis and lower extremities.
P
OSTURAL CHANGESDuring pregnancy, changes occur to
d f bd i l h
accommodate for abdominal growth:
a. Postural changes include forward head rounded shoulders increased head, rounded shoulders, increased lumbar lordosis, hyperextended knees and pronated feet.
b. The center of gravity shifts forward,
lti i b l di t b
resulting in some balance disturbance.
c. Muscular changes are also typical and
i l d h t d hi fl l b k
include shortened hip flexors, lower back musculature, and pectorals. Abdominal muscles neck and upper back muscle muscles, neck, and upper back muscle groups elongate. This may promote stretch weakness.
Postural changes in pregnancy
d. Bones and joints:
There is tendency to decalcification of There is tendency to decalcification of bones, sublaxation of joints due to softening of ligaments by relaxin hormone. It is more marked in sacroiliac joint and symphysis pubis, leading to
ddli it waddling gait.
CUTANEOUS SYSTEM
Due to overstretching of the skin, the elastic fibers Due to overstretching of the skin, the elastic fibers may rupture together with small blood vessels, so red streaks appear; known as striae gravidarum.
Th ll k d belo the
They are usually more marked below the umbilicus, on the breasts and may appear on the buttocks and thighs. In some women they are not marked or even don't appear during pregnancy.
After labor, the red striae become pale and white due to fibrosis and are known as striae albicantes.
Stria Gravidarum
Pigmentation: It is due to suprarenal changes, it usually begins to appear after the 4th month of pregnancy The pigmentation may appear
pregnancy. The pigmentation may appear : commonest sites are anywhere but the
1. Linea nigra: It is a line of pigmentation
between the umbilicus and the symphysis pubis.
2 Increased pigmentation of the nipple as primary 2. Increased pigmentation of the nipple as primary areola and appearance of secondary areola.
3. Cloasma gravidarum or mask face of pregnancy which is butterfly pigmentation of the forehead, nose, upper lip and the adjoining parts of the checks.
Thi i t ti ll di b t
This pigmentation usually disappears but may persist in some cases.
Butterfly pigmentation
MATERNAL WEIGHT GAIN
In normal pregnancy, the average gain is 0.3 K / k t 18 k 0 45 K / k f 18 Kg/wk up to 18 weeks, 0.45 Kg/wk from 18 28 weeks and a rate of 0.35 ‐ 0.4 Kg/week until
term.
Failure to gain weight and sometimes slight weight loss may occur in the last 2 weeks.
The average weight gain for the primigravidae is 12.5 Kg. and is
b bl b t 9 K f th
probably about 9 Kg for the multigravidae.
Acute excessive weight gain is commonly associated with abnormal fluid retention.
C
AUSES OF WEIGHT GAINWeight gain is caused by:
1. Fetus weight 3.63-3.88 Kg 1. Fetus weight 3.63 3.88 Kg
2. Placental weight 0.48-0.72 Kg 3. Amniotic fluid 0.72-0.97 Kgg
4. Uterus and breasts 2.42-2.66 Kg 5. Blood and fluid 1.94-3.99 Kgg
6. Muscle and fat 0.48-2.91 Kg Total = 9.70-14.55Kg
NERVOUS SYSTEM
-Functional changes may appear especially in neuroticg y pp p y women being sleepy and depressed while others become irritable, excited and suffer from insomnia
insomnia.
- The nausea and vomitingg may have a neuroticy element.
- Change of appetite such as refusal of some types of food.
-Neuralgias
