physiological changes in pregnancy mrs. mahdia samaha

Physiological changes in pregnancy

Mrs. Mahdia Samaha

04/19/23Mrs. Mahdia Samaha Kony2

Pregnancy is a load causing alterations not just in the mother’s

pelvic organs but all over the body. Fetal physiology is different from that of an adult,

but it interacts with the mother’s systems, causing adaptation and change of function in her body. These adaptations generally move to minimize the stresses imposed and to provide the best environment for the growing fetus; they

are usually interlinked smoothly so that the effects on the

function of the whole organism are minimized.

Cardiovascular system

04/19/233

Increased load on the heart in pregnancy is due to greater needs for oxygen in the tissues:

The fetal body and organs grow rapidly and its tissues have an even higher oxygen consumption per unit volume than the mother’s.

The hypertrophy of many maternal tissues, increases oxygen requirements.

The mother’s muscular work is increased to move her increased size and that of the fetus.

Mrs. Mahdia Samaha Kony

Cardiac output

04/19/234

C/O is increased in pregnancy by a rise in pulse rate with a small increase in stroke volume

Cardiac muscle hypertrophy occurs so that the heart chambers enlarge and output increases by 40%; this occurs rapidly in the first half of pregnancy and steadies off in the second.

In the second stage of labour, cardiac output is further increased, with uterine contractions

increasing output by a further 30% at the height of the mother’s pushing.


Position of the heart during preg.

04/19/235

During pregnancy the heart is enlarged and pushed up by the uterus .

The aorta is unfolded and so the heart is rotated upwards and outwards.

This produces electrocardiographic and radiographic changes which, although normal for pregnancy.


Blood pressure

04/19/236

May be reduced in mid-pregnancy pulse pressure is increased peripheral resistance generally decreases

during late pregnancy.


04/19/237 Mrs. Mahdia Samaha Kony

Blood volume

04/19/238

Maternal blood volume increases, the changes in plasma volume being proportionally greater than the increase in red cell bulk.

Haemodilution occurs Called a physiological anaemia.


The heart sounds

04/19/2310

The heart sounds are changed: A systolic ejection murmur is common. A third cardiac sound is commonly heard

accompanying ventricular filling.


The electrical activity of the heart on an electrocardiogram changes.


The ventricles become hypertrophied, the left to a greater extent than the right and therefore left ventricular, QRS deviation.

Heart valves and chamber volumes may change during pregnancy.

The heart becomes more horizontal so cardiothoracic ratio is increased and it has a straighter upper left border.

These changes can be visualized by cross-sectional echocardiography, which depends on the reflection of high frequency sound from inside the heart.

Respiratory system

04/19/2312

Changes in chest radiographs in normal pregnancy

Lungs• Show increased vascular soft tissue• Often have a small pleural effusion especially straight

afterdelivery Only when there are strong indications should chest

radiography be performed in pregnancy In early pregnancy women breath more deeply but

not more frequently under the influence of progesterone.

Alveolar ventilation is increased by as much as a half above pre-pregnant values so that PO2 levels rise and carbon dioxide is relatively washed out of the body.


Respiratory system

04/19/2313

Later the growing uterus increases intra-abdominal pressure so that the diaphragm is pushed up and the lower ribs flare out.

Expiratory reserve volume is decreased but the vital capacity is maintained by a slight increase in inspiratory capacity because of an enlarged tidal volume.

This may lead to a temporary sensation of breathlessness.


Urinary system

04/19/2316

Changes in clearance Renal blood flow is increased during early

pregnancy by 40%. The increase in glomerular filtration rate is

accompanied by enhanced tubular reabsorption Plasma concentrations of urea and creatinine

decrease.


Urinary system

04/19/2317

The muscle of the bladder is relaxed because of increased progesterone.

Increased frequency of micturition due to increased urine production is a feature of early pregnancy.

Later the bladder is mechanically pressed on by the growing uterus.


Urinary system

04/19/2318

The ureters become larger, wider, and of lower tone.

Sometimes stasis occurs in the ureters; therefore proliferation of bacteria and the development of urinary infection is more likely to occur.


Endocrine system

04/19/2320

All the maternal endocrine organs are altered in pregnancy, largely because of the increased secretion of trophic hormones from the pituitary gland and the placenta.


Pituitary gland

04/19/2321

The pituitary gland is increased in size during pregnancy, mostly because of changes in the anterior lobe.

Anterior lobe Prolactin. Within a few days of conception the rate

of prolactin production increases. Prolactin affects water transfer across the

placenta andtherefore fetal electrolyte and water balance. It is later concerned with the production of milk,

both initiating and maintaining milk secretion.


Anterior lobe of the pituitary gland

04/19/2322

Gonadotrophins. The secretions of both follicular stimulating hormone and luteinising hormone are inhibited during pregnancy.

Growth hormone. The secretion of growth hormone is inhibited during pregnancy, probably by human placental lactogen.

Adrenocorticotrophic hormone concentration increases slightly in pregnancy despite the rise in cortisol concentrations.

Thyrotrophin secretion seems to be the same as

that in non-pregnant women. Mrs. Mahdia Samaha Kony

Posterior lobe of the pituitary gland

04/19/2323

Oxytocin which is released from the pituitary gland during labor to stimulate uterine contractions.

Its secretion may also be stimulated by stretching of the lower genital tract.

Oxytocin is also released during suckling and is an important part of the let down reflex.


Thyroid gland

04/19/2324

Pregnancy is a hyperdynamic state and so the clinical features of hyperthyroidism may sometimes be seen.

The basal metabolic rate is raised and the concentrations of thyroid hormone in the blood are increased, but thyroid function is essentially normal in pregnancy


Adrenal gland

04/19/2325

The adrenal cortex synthesises cortisol from cholesterol.

In pregnancy there is an increase in adrenocorticotrophic hormone concentration along with an increase in total plasma cortisol concentration because of raised binding globulin concentrations.

The cortex also secretes an increased amount of renin, possibly because of the increased oestrogen concentrations.


Adrenal gland

04/19/2326

Renin produces angiotensin I, which is associated with maintaining blood pressure.

Increase production of aldosterone Retention of sodium by the kidneys Results in edema Usually recommend no added salt intake. Some renin also comes from the uterus and the

chorion


Adrenal glands

04/19/2327

Increase production of aldosterone Retention of sodium by the kidneys Results in edema Usually recommend no added salt intake.


Placenta

04/19/2328

The oestrogen, progesterone, and cortisol endocrine functions of the placenta.

In some susceptible women, progesterones may soften critical ligaments so that joints are less well protected and may separate (e.g. separation of the pubic bones at the symphysis).


`INTEGUMENTARY SYSTEMCAUSES:1.Hormonal alterations2.Mechanical stretching Hyper pigmentation is stimulated by APGH

melanotropin. Darkening of the nipples, areola,, axillae, and

vulva at 16th week gest. Facial melasma(cholasma), or mask of preg: is

a brown hyper pigmentation of the skin over the cheeks, nose, and forehead especially in the dark woman


Linea nigra:

Is a pigmented line extend from the symphysis pubis to the fundus in the midline, it is known as linea alba before preg. Not all pregnant women develop LN.

Stria gravidarum, or stretch marks, appear in 50% to 90% of pregnant women at the second half of preg.

It reflect separation within the underling connective tissue (collagen)

Common sites are the abdomen, thighs, breasts. Its color vary; in with light skin: pinkish In dark skinned women: lighter than the surrounding

tissue. In multiparas: appears silvery in light skinned women

and purplish in in dark skinned women.


Gum hypertrophy (epulis): is a red, raised nodule on the gums that bleeds easily. Advice woman to avoid trauma, it will disappear after delivery.

Nail growth can be accelerated, but soft and thin. Oil skin and acne Vulgaris may appear Clear and radiant skin in some women. Hirsutism is commonly reported Increased blood supply to skin lead to increased

perspiration Women feel hotter during preg. Related to increase

progesterone which leads to increase basal metabolic rate.


Genital tract

04/19/2332

The uterus changes in pregnancy; the increase in bulk is due mainly to hypertrophy of the myometrial cells, which do not increase much in number but grow much larger.

Oestrogens stimulate growth, and the stretching caused by the growing fetus and the volume of liquor provides an added stimulus to hypertrophy.


Genital tract

04/19/2333

The blood supply through the uterine and ovarian arteries is greatly increased so that at term 1.0–1.5 L of blood are perfused every minute.

The placental site has a preferential blood supply, about 85% of the total uterine blood flow going to the placental bed.


Genital tract

04/19/2334

The cervix, which is made mostly of connective tissue, becomes softer after the effect of oestrogen on the ground substance of connective tissue encourages an accumulation of water.

The ligaments supporting the uterus are similarly stretched and thickened.


Musculoskeletal Systems

04/19/2335

Relaxation and increased mobility of pelvic joints. Posture is affected with shift in center of gravity

forwards. Backache Waddling gait( the proud walk of pregnancy) Increase in lumbosacral curve( lordosis) Aching, numbness, and weakness of the upper

extremities may result. Slight relaxation and increased motility of the pelvic

joints Obesity and multifetal pregnancy tend to increase

pelvic instability


Estrogen and relaxin hormones aid in relaxation and softening

During the third trimister the rectus abdominis muscle may separate, allowing the abdominal content to protrude at the midline. The umbilicus flatness or protrudes.


Nervous system

04/19/2337

Mood changes during pregnancy Post-partum blues Usually mild, but true psychosis may develop in rare

cases. Food cravings: Unusual/strange food combinations Non-food substance (pica) Compression of the pelvic nerves sensory changes

in the legs Lordosis pain Edema involve the peripheral nerves carpal tunnel

syndrome.Mrs. Mahdia Samaha Kony

Carpal tunnel syndrome. Parasthesia Pain in the hands radiating to the elbow The sensation are caused by edema that compresses the

median nerve beneath the carpal ligament of the rest. Smoking and alcohol consumption can impair the

microcirculation and worsen the symptoms The dominant hand mostly affected Symptoms regress after pregnancy Acrosthesia: numbness and tingling of the hands Tension headache is common A light headnes, faintness, are common in early pregnancy Hypocalcemia may cause neuromuscular

problems( tetany)


Gastrointestinal System

04/19/2339

Heartburn, flatulence, and nausea and vomiting with reduced peristalsis

Slower peristalsis also results in constipation Appetite: early in preg. The woman has nausea

and vomitting due to increase hCG and altered carbohydrate metabolism

pica: nonfood cravings such as ice, clay, and changes in the dietary intake due to changes in the sense of taste.


Mouth The gum become hyperemic, spongy, and

swollen during pregnency. Bleeding gums, with softening of gums

with >>estrogen. Ptylism in some women: excessive salivation


Esophagus, stomach and intestine Hiatal hernia occurs after the 7th or 8th month of preg in about 15%-

20%

It occurs in mulipara than nullipara

Increased estrogen production cause decrased secretion of hydrochloric acidthre fore peptic

ulcer is uncommon during pregnency

Increased progesterone production causes decrease tone and motility of smooth muscle Resulting in esophageal regurgitation, slower emptying

time of the stomach.As a result woman may experience indigestion or heart

burn ( pyrosis) Increased progesterone, cause loss of muscle tone and

decrease peristalsis result in increase water absorption from the colon and cause constipation


Gall bladder and liver The gall bladder is often distended because fo

decrease its muscle tone Increase emptying time and thickening of the

pile caused by prolonged retention Increased progesterone lead to

hypercholestremia which may increase the chance of GB stone formation during pregnancy


physiological changes in pregnancy mrs. mahdia samaha

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