Tanoj Patidar MSC NURSING. TOPIC : systemic changes during antenatal period OBGY and midwifery Nursing

1. BY- TANOJ PATIDAR
MSC NURSING

2.  The major respiratory changes in pregnancy are caused by the
mechanical effects of the enlarging uterus, the increased total body
oxygen consumption and the respiratory stimulant effects of
progesterone.
 As pregnancy progresses, the enlarging uterus places pressure
upward toward the lungs and elevates the position of the diaphragm.
This results in lower intrathoracic pressure and decreased resting lung
volume, creating a decreased functional residual capacity (FRC) in the
lungs.
 Reduction in the expiratory reserve volume and the residual volume
of the lungs contribute to the reduced FRC. The movement of the
diaphragm and the thoracic muscles is not impaired by the enlarging
uterus; thus, the vital capacity of the lugs is unchanged.

3.  With the pregnancy , total body oxygen consumption increase about
15-20% , primarily due to increase needs of the uterus and its content.
 More oxygen is required for increased renal and cardiac work with
the small increments needed for the work of the respiratory muscles
and the breasts.
 During pregnancy , the increases in cardiac output and alveolar
ventilation are greater than those needed to meet increased
oxygen consumption . Therefore, despite the rise in total oxygen
consumption , the arteriovenous oxygen difference and arterial
PCO2 fall , indicating hyperventilation.

4.  Progesterone increases ventilation, making the respiratory
center more sensitive to CO2.
 In hyperventilation of pregnancy, the PCO2 falls to a level of
27-32 mm Hg, producing respiratory alkalosis. There is
corresponding rise in the arterial PO2 to about 106-108 mm
Hg in the first trimester, with a slight downward trend as
pregnancy progresses.

5. TESTS DESCRIPTION CHANGE IN
PREGNANCY
Respiratory rate Breaths per minute unchanged
Inspiratory capacity Maximum volume air inspired
from the resting level
Increased about 5%
Tidal volume Volume air inspired and
expired each breath
Rises 40% in pregnancy
Functional residual capacity Volume air in lung at resting
expiratory level
Decreased about 80%
Vital capacity Maximum volume air forcibly
inspired
Unchanged , may be small
decreased at term
Minute ventilation Volume air inspired or
expired in 1 minute
Increased about 40%
Expiratory reserve volume Maximum volume air expired
after normal expiration
Decreased about 15%

6. Dyspnea is common during pregnancy. While the respiratory rate dose
not change during pregnancy , there is a rise in minute ventilation ,
reflecting about a 40 % increase in tidal volume at term . The
increased size of the uterus and the corresponding displacement of
abdominal contents also may affect respiration ,while airway
resistance is generally unchanged.
This may be related to greater differences between non-pregnant and
pregnant PCO2 levels in susceptible women. there are no substantial
differences in pulmonary function tests between pregnant women with
dyspnea and those who do not experience this symptom.

7. Besides morning sickness, several gastrointestinal system changes
occur during pregnancy .
Mouth and gums: Vascular swelling of the gums is called as epulis of
pregnancy . The gums become hyperemic and softened, with an
increased tendency towards bleeding after brushing the teeth. These
changes do not lead to an increased incidence of the tooth decay and
usually regress spontaneously after delivery. Additional vitamin C in
the diet may decrease of tendency. Consultation with dentist should be
encouraged if the bleeding gums become a persistent problem.
Stomach and intestines: The intestine and stomach are displaced
upward by the enlarging uterus. These positional changes may alter
the physical findings in certain disease, such as appendicitis. The
appendix is usually displaced some what laterally and upward and at
time may be located as high as the right flank. This also accounts for
the increase in gastric reflux and the resulting sensation of
“heartburn”.

8. Mobility and Muscular tone: The motility in the gastrointestinal
tract is decreased, resulting in a prolonged gastric emptying time and
a longer intestinal transit time. A generalized relaxation of the smooth
musculature of the gastrointestinal tract occurs under the influence of
progesterone constipation and heartburn often result.
Muscular tone around the stomach and esophagus is altered, resulting
in lower intraesophageal pressures, higher intragastric pressures, and
slower esophageal peristalsis. All of these changes contribute to gastro
esophageal reflux.
Digestion: Appetite may be decreased in early pregnancy in
association with nausea. As the digestive system become accustomed
to its new conditions, the appetite is increased. Because of organ
displacement and diminished tone, stomach emptying time is
decreased, and feelings of fullness are increased.

9. Women may need small, frequent meals, rather than three large meals
diet teaching should focus on food quality rather than quantity to
provide optimal nutrition. Adequate dietary intake of fiber and fluids
can help to decreased constipation.
Liver and Gall Bladder: No characteristic changes in liver
morphology occur during normal pregnancy, but some of the
laboratory tests for hepatic function are altered :
 Total alkaline phosphates activity in serum doubles, reaching levels
that would be abnormal in the non-pregnant state.
 Serum cholinesterase activity normally falls during pregnancy
Leucine aminopeptidase activity (serum) is markedly elevated.
 Gall bladder function is affected by decreased tone and distention ,
leading to prolonged emptying time and incomplete evacuation. This
may account for the increased predisposition to gallstones during
pregnancy.

10. Along with increase in frequency of urination , the renal system also
under goes certain changes :
 The urine in pregnancy usually is increased in amount and has a lower
specific gravity .
 There is a decrease in the renal threshold for glucose ,and urine may
test positive for sugar, even without other symptoms of diabetes.
While “spilling sugar” or lactosuria is common, it should be
investigated within the course of antenatal care.
 Renal function tests may be altered , including the flowing:
 Decreased plasma creatinine
 Decreased urea concentration
 Decreased urine concentration
 The ureters become markedly dilated during pregnancy, particularly
the right ureters. .

11.  Renal plasma flow and the glomerular filtration rate begin to increase
in early pregnancy, reaching a plateau by midpregnancy at about 40%
above nonpregnant levels. This persists unchanged until term. The
exact mechanism of these changes is unclear; although partially
related to the increased plasma volume in pregnancy, the renal
changes reach a peak relatively early in pregnancy, before the
maximum increase in plasma volume occurs.
 Plasma concentrations of rennin, rennin substrate, and angiotensin 1
and 2 are increased during pregnancy. Rennin levels remain elevated
throughout pregnancy; some of this elevated rennin may represent a
different high molecular weight form or inactive form of the enzyme .
The uterus and kidneys can produce rennin , and high concentrations
of rennin are found in the amniotic fluid. The role of rennin in
amniotic fluid is not fully understood.

12.  The bladder usually functions efficiently during Pregnancy .The
urinary frequency experienced in the first few months of pregnancy is
caused by hormonal effects and pressure exerted on the bladder by the
enlarging uterus. Mechanical frequency is observed again when
lightning occurs before the onset of labor. Urinary tract infection,
especially cystitis, are not uncommon during pregnancy and may be
related to urinary stasis and inadequate emptying of the bladder.

13. The fetoplacental-maternal unit is very important in the normal
functioning of pregnancy. This maternal endocrine adaptation to
pregnancy is comprised of hypothalamus, pituitary, parathyroid,
thyroid, and adrenal glands, and ovaries which are responsible for the
maintenance of the fetoplacental-maternal unit.
PLACENTA: The placenta function as the major Endocrine gland
during pregnancy, secreting four Hormones that are vital to
maintaining the pregnancy. The early chorionic villi of the Implanted
ovum secrete human chorionic gonadotropin (HCG), which prolongs
the life of the corpus luteum. The result is the continued production
of estrogen and progesterone, which are necessary to maintain the
endometrium. During pregnancy, HCG appears in maternal blood
and is excreted in the mothers Urine, allowing diagnosis of
pregnancy by tests Discussed later in the chapter under the heading
“Laboratory Evaluation”.

14. The chorionic cells of the placenta produce another unique hormone,
human chorionic Somatomammotropin, which also is known as
Human placental lactogen (HPL). This hormone is detectable in
placental cells as early as the third week after ovulation and is found
in Maternal serum by the sixth week. It influence Somatic cell growth
of the fetus and facilitates preparation of the breasts for lactation.
In addition, the placenta takes over the Production of estrogen and
progesterone from the ovaries and after the first 2 months of
Gestation, becomes the major source of these Two hormones.
The increase in these hormones In the maternal organism is thought to
be responsible for many important changes that take place during
pregnancy , Such as the growth of the uterus and the development of
the breasts . in the breasts , the development of the duct system is
promoted by estrogen ,and the development of the lobule–alveolar
system is promoted by progesterone.

15. THE PITUITARY BODY: The pituitary gland enlarges somewhat
during pregnancy but is not essential for the maintenance of
pregnancy .The anterior lobe of this small gland ,located at the base of
the brain ,is called the master clock ,which , under the influence of the
hypothalamus , controls the menstrual cycle. In addition to
gonadotropins , the anterior lobe secretes hormones that act on the
thyroid and adrenal gland and another hormone that influence the
growth process. Production of these hormones continues during the
pregnancy. Gonadotropin, on the other hand , are no longer cyclically
released. The estrogen and progesterone produced by the placenta
inhibit their release from the pituitary gland .
The posterior lobe of the pituitary secretes an oxytocic hormone,
oxytocic , which has a strong stimulating effect on the uterine muscle.

16. Extract of the pituitary gland that contains oxytocin are widely used in
obstetrics for the following :
 To stimulate or augment contraction during labor
 To stimulate the uterus to contract after delivery , thereby diminishing
postpartum hemorrhage
 To stimulate lactation .
 THYROID GLAND: During pregnancy , there is slight to moderate
enlargement of the thyroid . This hypertrophy of thyroid tissue is not
associated with increased thyroid activity , although an elevation in
the basal metabolic rate increases throughout the course of pregnancy
. This is a reflection of the increased oxygen consumption as a result
of the metabolic activity of the products of conception.

17. Other parameters for the measurement of thyroid function display
changes. The serum protein –bound iodine ,butyl extractable iodine,
and thyroid (T4) levels increase, and the elevated levels are
maintained until shortly after delivery. The increase is not due to
increased thyroid activity ,but to an elevation in the level of thyroid –
binding protein normally present in the blood. Thus although the
amount of circulating thyroid hormones and therefore the total
concentration of hormone are elevated ,the actual amount of unbound
or available hormone remains within normal limits. The
triiodothyronine up take test displays decreased values in pregnancy,
which indicates an increase in the binding of circulating
triiodothyronine. A similar increase in the level of thyroid –binding
proteins is seen in the non pregnant client after the administration of
estrogen ,and it is likely that in pregnancy, the increase is a reflection
of the high level of circulating estrogen.

18. ADRENALS: The adrenal cortex hypertrophies during pregnancy ,and
its activity increase . The actual secretion of cortisol by the adrenals is
unchanged ,although the metabolism of cortisol is altered as a result
of the influence of estrogen. There is an increase in the production by
the adrenal glands of aldosterone , the hormone responsible of the
retention of sodium by the kidneys.
This increase begins early in pregnancy and continues throughout. The
result of the increase is decreased ability of the kidneys to handle salt
during pregnancy, leading to some fluid retention and either occult or
overt edema.
OVARIES: The ovaries ,except for the activity of the corpus luteum of
pregnancy, remain relatively quiescent. Gonadotropins levels are low,
because their release is inhibited by the estrogen and progestrone
produced by the placenta. Thus, follicular activity in the ovary is
suppressed and there is no further ovulation until after delivery.

19. Metabolic changes in pregnancy reflect the increased demands of the
growing fetus on the body. Weight gain, associated with the presence
of the fetus, placenta, fetal membranes, and amniotic fluid, is
minimally affected by metabolic changes.
Protein Metabolism: There is a positive nitrogenous balance
throughout pregnancy at time, the fetus and placenta contain about
500gm chiefly distributed in the uterus, breasts and the maternal
blood. As the breakdown of amino acid to urea is suppressed, the
blood urea level falls to 15-20 mg% blood uric acid and cretonne
level, however either remain in changed or fall slightly. Amino acid
are actively transported across the placenta to the fetus.

20. Carbohydrate Metabolism: Pregnancy has a marked influence on
carbohydrate metabolism . In general, levels of fasting blood sugar are
lower and insulin requirements are elevated in many women. This
mechanism may actually Induce gestational diabetes of mellitus,
which is responsible for babies of high birth weight (macrosomia) and
other complications.
Fat Metabolism: An average of 3-4kg of fat is stored during
pregnancy mostly in the abdominal wall, breast hips and thighs.
Plasma lipids and lipoproteins increase appreciably during the later
half of pregnancy due to increased estrogen, progesterone HDL and
lepton levels.

21. Lipid Metabolism: HDL level increase by 15% LDL is utilized for
placental steroid synthesis. This hyperlipidemia of normal pregnancy
is not atherogenic leptin, a peptide hormone , is secreted by the
adipose tissue and the placenta. It regulates the body fat metabolism.
Iron metabolism: Iron is absorbed in ferrous from duodenum and
jejunum and is released into the circulation as transferring. About
10% of ingested iron is absorbed. Iron is transported actively across
the placenta to the fetus. Iron requirement during pregnancy is
considerable and is mostly limited to the 2nd half of pregnancy
specially to the last 12 weeks. Total iron requirement during
pregnancy is estimated approximately 100mg.