Physical Changes During Pregnancy

Let us discuss all the physical changes during pregnancy.

Vaginal Changes During Early Pregnancy

i) It becomes Vascular.

ii) Looks bluish (Jacquemier’s sign)

iii) Is soft when felt.

iv) Vaginal secretions are acidic.

v) Anaerobes become more i.e. 5 times than aerobes.

vi) Cytological studies show navicular cells i.e. pregnancy cells in clusters.

Vulva

It beomes Vascular, hypertrophied, pigmented and in some woman varicose veins appear.

UTERUS

During pregnancy there is increase in weight and ength of uterus. Changes occur in body, isthmus and ervix.

(i) Weight of Uterus

Gravid Uterus enlarges from 50 gm to 900-1000 gms.

(ii) Length of Uterus

Non-pregnant uterus measures 7.5 cm in length but in pregnancy its length increases to 35 cm.

(iii) Volume of Uterine Cavity

In non-pregnant state the volume of uterine cavity is 10 ml and increases to 5 litres.

(iv) Muscles

(a) Three distinct layers of uterine muscles develop.

(i) Outer Longitudinal layer.

(ii) Middle Vascular Layer.

(iii) Inner Circular Layer.

(b) Uterine Muscle fibres undergo hyperplasia and hypertrophy upto 12 weeks then they hypertrophy and elongate throughout pregnancy.

(c) Contractile protein (Actinomycin) increases, Muscles contract and relax.

(d) Uterine vessels increase in size and number.

Changes in Isthmus

(a) During pregnancy lower uterine segment is formed of isthmus.

(b) Upto 12 weeks Isthmus elongates. Then it forms thin lower uterine segment unfolding its cavity from above downward to be included in the uterine cavity.

(c) It dilates during last trimester as hemispherical segment.

(d) At term it measures 7.5 cm-10cm in length.

(vi) Cervix-Cx

(a) During pregnancy Cx becomes vascular oedematous and soft.

(b) Its length becomes double & volume inceases.

(c) Mucosa hypertrophies.

(d) Endocervical epithelium grows.

(e) Mucus production increases to plug the canal.

(f) Cervical stoma synthesis protein fibrils collagen.

(g) During labour and pre-labour, collagen decreases due to lysis by collagenase enzyme.

(h) Ground substances (Glycosaminoglycans) increases and loosens, thus cervix becomes soft.

FALLOPIAN TUBES

a) They hypertrophy, become vascular with patchy decidua.

b) Ovaries hypertrophy and become vascular.

c) Ovulation ceases (Stops) throughout pregnancy.

d) Corpus Luteum of menses persists and enlarges to 2.5cm till 8th week on HCG effect of trophoblast.

e) Progesterone of corpus luteum supports decidua upto 7 weeks of pregnancy.

CHANGES IN BREAST

a) The vascularity and size of breast increases.

b) Total weight becomes 0.4 kg & volume 1½ times more.

c) Enlarged breasts from 16th week secretes a clear sticky yellowish fluid called colostrum.

d) Areola becomes dark pigmented (Primary Areola) with 5-15 hypertrophied sebaceous glands (Montgomery’s Tubercle)

e) Second zone of pigmentation appears around primary areola (secondary areola) during second trimester.

SKIN

a) There is Patchy Pigmentaion on face and cheeks called chloasma gravidarum.

b) From the symphysis pubis to xiphisternum there is linear black pigmentation called Linea Nigra.

(c) During 2nd half of pregnancy, below the umbilicus appears whitish pink streaks or lines more towards the flanks. These are called striae gravidarum.

CHANGES IN HAIR GROWTH

Proportion of hair growth rises to 95% from 85% (non-pregnant) with hair falling during puerperium.

Pregnancy Weight Gain by Trimester

As we all know pregnancy is a growth period. Thus a pregnant woman gains 11kg weight on an average varying from 6-15kg from a singleton pregnancy.

This has been distributed as follows:

First trimester 1 kg

Second trimester 5 kg

Third 5 kg

On the other hand the total weight gain in terms is as written below:

1. REPRODUCTIVE WEIGHT GAIN = 6 KG

It includes

2. NET MATERNAL WEIGHT GAIN

At the end maternal weight gain promotes fetal weight gain.

Blood in Pregnancy

1. BLOOD VOLUME

The blood volume is markedly raised during pregnancy.The blood volume starts to increase from about 10th week, expands rapidly thereafter to maximum 40% above the non-pregnant level at 30-32 weeks. Up to term, the level is essentially unchanged.

2. PLASMA VOLUME

The plasma volume increases during pregnancy. This is due to the increased circulating steroids (oestrogen, progesterone and aldosterone). A 1.25 litre rise in total plasma volume occurs.

3. R.B.C. AND HAEMOGLOBIN

The R.B.C. volume is increased about 250ml, the amount to be regulated by increased demand of oxygen transport during-pregnancy.

4. LEUCOCYTES

Neutrophilic leucocytosis can reach levels of 15,000 to 20,000 cu/mm and even higher during labour. The growth in both mature and immature neutrophil numbers is what caused the increase.

5. TOTAL PROTEIN

Total protein rate increases from normal 180gm in non-pregnant women to 230 gram at term. However due to haemodilution, the plamsa protein concentration falls from 7 gm% to 6 gm%. In the same manner. Albumin level is decreased in pregnancy and globulin level is slightly increased and albumin globulin ratio is decreased to 1.1 from 1.7: 1.

6. BLOOD COAGULATION FACTORS

Fibrinogen level is raised by 50% from 200-400 mg% in non-pregnant to 300-600 mg% in pregnancy. ESR values are significantly greater (by a factor of four) during pregnancy. Up to 15 minutes following delivery, there is a reduction in fibrinolytic activity.

Cardiovascular Changes in Pregnancy

1. CARDIOVASCULAR CHANGES

Heart works more during pregnancy, increases its volume by 10% but no change in ECG except slightly left axis deviation.

2. CARDIAC OUTPUT

In supine position cardicac output per beat increases from 3rd month, rises to 30% above normal at 30th week, remains at 15% above during last month Cardiac Output increases due to increased heart rate stroke volume.

3. PULSE RATE

Near term increased by 10/min.

4. BLOOD PRESSURE

Remains within normal limits with midpregnant drop in Blood Pressure in some women.

5. VENOUS PRESSURE

Femoral venous pressure rises from 10cm water (pregnancy) to 30 cm water. This is brought on by the gravid uterus’ pressure on the pelvic veins. One-third of circulation blood volume goes to lower limbs due to venous dilation on progesterone effect. As a result physiological oedema of feet and ankle occurs and also that of piles and varicose veins in legs.

6. BLOOD VOLUME

Increases from 3rd month, reaches a peak of 25% rise (1000 ml) at 32 weeks and then plateaus off till term.

7. RED CELL VOLUME

(a) Red cell volume increases by 200 ml (5-10%)

(b) Due to hemodilution the hematocrit value falls in peripheral blood.

(c) GSR increases to 40-45 mm (first hour) due to increased fibrinogen content.

(d) Due to increased consumption platelete count slightly decreases.

(e) Clotting factors rise (factor VII, VIII, IX, X) Plasma antithrombin III and fibrinolytic activity decreases.

(g) There is no marked change in bleeding and clotting times.

CHANGES IN RESPIRATORY SYSTEM IN PREGNANCY

(a) Mucosa of upper respiratory tract shows hyperaemia and congestion.

(b) Tidal Volume rises to 700ml.

(c) Plasma bicarbonate and cations (Na, K, Ca) falls.

(d) Blood pH rises from 7.40 (non-pregnant) to 7.44.

(e) Respiratory rate rises from 15-18/min.

WATER AND ELECTROLYTE METABOLISM IN PREGNANCY

(a) Water requirement increases in pregnancy.

(b) Water retention comes to 6.5L during pregnancy.

(c) Thirst increases during pregnancy.

(d) Daily requirement of water comes to 2½ L.

(e) Sodium retention occurs as

Total 20 gm

1. Mother 10gm
2. Fetus 10 gm

Potassium retention Occurs to 10 gm

1. Mother 3.5 m (1/3rd)
2. Fetus 6.5gm 2/3^rd

CHANGES IN URINARY TRACT DURING PREGNANCY

1. BLADDER

(a) During early pregnancy due to effect of gravid uterus there occurs frequency of urine.

(b) Late pregnancy urine frequency is due to fetal head pressure.

(c) Bladder muscles Hypertrophy.

(d) Intra vesical pressure rises throughout pregnancy.

2. URETERS

(a) Renal pelvis and ureters dilate (due to progest- erone and around uterine pressure effect) from 12th week, becomes maximum at Mid-Pregnancy and subsides by 6th week post partum.

(b) Right one cliates more.

(c) Kinking of ureters and urinary stasis occur & these favour infection.

(d) Glomerular, renal blood flow increases during pregnancy.

3. RENAL FUNCTION

(a) There is increase in glomerular filtration rate.

(b) In late pregnancy water and salt excretion decrease and urinary output is reduced.

(c) Due to increased GFR plasma urea and creatinine decrease.

(d) Rate of urine formation slightly increases because of increased load to excretory products.

CHANGES IN METABOLISM DURING PREGNANCY

CHANGES IN METABOLISM OCCUR IN

(a) Protein metabolism.

(b) Carbohydrate metabolism.

(c) Calcium metabolism.

(d) Iron metabolism.

CHANGES IN PROTEIN METABOLISM

(a) Protein storage occurs.

(b) Conversion of amino acid to urea is suppressed.

CHANGES IN CARBOHYDRATES

(a) Normal pregnancy shows fasting hypoglycaemia (10mg% lowered glucose level) Post Prandial hyperglycaemia (raised blood glucose by 20-25mg %).

(b) Hyperinsulinaemia due to tissue resistance to Insulin.

(c) Foetal drainage causes fall in fasting blood glucose. Raised postprandial blood glucose is necessary to feed the foetus. Carbohydrate intakes increase during pregnancy to provide glucose and more calories.

(d) Fat is stored during pregnancy from glucose for future Lactation.

CHANGES IN FAT METABOLISM

(a) There is increased absorption of fat in later months of pregnancy. An average of 3-4kg fat is stored during pregnancy mostly in the abdominal wall, breasts, hips and thighs.

(b) Plasma lipids increases during pregnancy from 700mg% to 1050 mg% (c) Cholesterol rises from 120mg% to 280mg%

CHANGES IN IRON METABOLISM DURING PREGNANCY

(a) In pregnancy iron demand is increased and this iron is absorbed in ferrous form from duodenum & jejunum & is released into the circulation as transferrin.

(b) Iron is transported actively across the placenta to fetus.

(c) Total iron requirement during pregnancy is estimated approximately 1000mg.

(d) From daily breakdown of 40ml blood (0.8% red cell mass amounts to 21mg serum iron. Available food iron & iron from broken down RBC go to.

(f) Bone Marrow to form Hb (Haemoglobin) (ii) Storage 500mg in Reticulo-epithelial system “(liver spleen Bone Marrow)

(e) Iron storage is drained for Hb formation when enough Iron is not available from food and drug.

(i) Daily requirement of Iron for pregnant woman

Fetus – 400 mg

Placenta – 150 mg

Expanded red cell – 200 mg

= +750

Daily loss Img = – 280 mg

Requirement 1030 mg

then 1030 ÷ 280 days

= 3.8 mg daily requirement

This Iron requirement becomes highest during last 3 months of pregnancy since Fe is stored in fetal liver.

Requirement of Fe in food doubles during pregnancy i.e 35-40mg. This can meet daily 3.5 mg.

PHYSIOLOGICAL CHANGES DURING PREGNANCY IN THE ALIMENTARY SYSTEM

(a) In early pregnancy Nausea, Vomiting and loss of appetite occur in 50% women.

(b) Later appetite increases.

(c) The gums become congested, spongy and may bleed to touch.

(d) Due to high progesterone level, muscle tone and the motility of the entire GI tract is diminished.

(e) Heart burning occurs due to reflex of stomach contents through reflux cardiac sphincter of esophagus.

(f) There is a toxicity of gut that leads to constipation.

CHANGES IN THE NERVOUS SYSTEM

In some cases during pregnancy the nervous system gets affected. The changes are listed below:

(a) There are some sort of temperamental changes during pregnancy and puerperium.

(b) In a few due to psychological background Nausea Vomiting, mental irritability and sleeplessness is present.

(c) Due to Vitamin B1 deficiency (thiamine) there may be generalised Neuritis.

(d) Sometimes Compression of the Lumbosacra Trunk by the fetal head or by the prolapsed Intervertebral disc may produce features of sciatica or paralysis of some muscles of the leg.

(e) In the later months of Pregnancy Carpal Tunnel Syndrome may occur.

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