Systemic changes during pregnancy

Urinary system -
Renal blood flow increased by as much as 70-80%. Kidney
enlarge in length by 1%. Renal plasma flow is increased by
50-75% maximum by 16th week and is maintained until 34 week.
Glomerular filtration rate (GFR) is increased by 50% all through
pregnancy. Increased GFR causes reduction in maternal plasma
level of creatinine. In late pregnancy, the bladder mucosa become
edematous due to venous and lymphatic obstruction specially in
primary gravida. Increased frequency of micturition is noticed at
6-8 weeks of pregnancy which subside after 12 week.


Alimentary system -
The gums become congested and spongy. Muscle tone and motility
of entire gastrointestinal tract are diminished due to high progesterone
level. Cardiac sphincter is relaxed and regurgitation of acid, gastric
content into the esophagus (This is known as Morning sickness),
may produce esophagitis and heart burn. Around 4-8 week most
woman start complaining of nausea and vomiting witch may
continued until about 14-16 week.


Liver and gall bladder - 
There is no histological changes in liver cells but the functions are
depressed. There is marked atonicity of gall bladder. This, together
will high blood cholesterol level during pregnant which can lead to
gall stone.


Nervous system - 
Some Temperamental changes are found during pregnancy and
in the puerperium. Nausea, vomiting, mental irritability and
sleeplessness are probably due to some psychological background.
Postpartum blues, depression or psychosis may develop in a
susceptible individual.

Dietary and Metabolic changes during pregnancy

Total metabolism is increased due to the needs of growing uterus and fetus. There is increased food intake during pregnancy. Gastrointestinal changes lead to characteristic alteration in the metabolism of carbohydrate, protein and fat. These changes which are brought about by human placental lactogen ensure that glucose is readily available for body and brain growth in the developing fetus and protect against nutritional deficiency. A continuous supply of glucose must be available to transfer to the fetus.

As the nutritional demand of fetus increases in 2nd half of pregnancy, and insulin resistance increases metabolisation of fat stores laid down in 1st half of pregnancy which provide extra energy to mother, However because of increase concentration of fatty acid resulting from this process , the mother is more prone to ketosis. Even and overnight fast of 12 hr will result in hypoglycemia and increased production of keton bodies. Restriction of carbohydrate in any diet may be avoided and mother may be encouraged to take bed time snacks.

Iron is very important mineral in pregnancy. Iron is absorbed in ferrous form by duodenum and jejunum. Iron is transported actively across the placenta to fetus. Total iron requirement during pregnancy is estimated approximately 1000 mg. In second half, daily requirement actually becomes very much increased to the extend of about 6-7 mg


Que.-  Why the continuous supply of glucose is necessary in pregnancy ?
           Why should pregnant woman not be skip meals ?

Ans.-  Pregnant woman should not keep fast and skip meals meals for following reasons -
          1. Maternal blood glucose level is critically important for the fetal well being.
          2. Fasting in pregnancy produce more intense ketosis known as accelerated starvation,
              that may be dangerous to fetal health.



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• Respiratory changes during pregnancy
• Vomiting in pregnancy (morning sickness)
• Changes occur during 11th week of pregnancy
• Diagnosis of pregnancy in third trimester
• Causes of IUGR
• Abruptio placentae (Early separation of placenta)

Heart and Circulatory changes during pregnancy

• The heart muscles particularly the left ventricle hypertrophy leading to enlargement of heart. The growing uterus pushes the heart upwards and to the left side.
• During pregnancy the heart rate and stroke volume ( The amount of blood pumped by the heart each beat ) increased.
• The cardiac output ( The rate which blood is pumped by heart expressed as liter/min. ) increased markedly  by end of the first trimester.
• Femoral venous pressure is markedly raised specially in the later months. It is due to pressure exerted by the gravid uterus on common iliac vein, more on right side due to dextrarotation of the uterus.

Que.-  Why the heart rate and stroke volume is increased during pregnancy ?

Ans.-  It is due to increased oxygen requirement of the maternal tissue and growing fetus. 
          Normal heart rate and stroke volume is not fulfill the needs of mother and fetus. So it is 
          increase in normal way.


Que.-  Why BP does not rise in pregnancy, although the cardiac output increased ?

Ans.-  In pregnancy, the BP does not rise because of the reduction in peripheral resistance. 
          The capacity of vein and venules increase. Arterial wall reflex and dilate due to the 
          effect of progesterone.

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Plasma protein changes during pregnancy

During the first 20 weeks of pregnancy, the plasma protein concentration reduced as a result of the increased plasma volume. This leads to lowered osmotic pressure contributing to edema of the lower limbs seen in late pregnancy.

Important - 

Plasma protein concentration falls from 7 gm% to 6 gm% due to hemodilusion. This result in diminished viscosity of the blood and reduce colloid osmotic tension because of marked fall in albumin level from 4.3 gm% to 3 gm%, a fall about 30%. And only slight rise of globulin (mainly alpha-globulin).

Plasma protein changes - 

	Non   Pregnant	Pregnancy  Near Term	Changes
Total protein (gm)	180	230	Increased
Plasma protine     concentration               (gm/100ml)	7	6	Decreased
Albumin        (gm/100ml)	4.3	3	Decreased
Globulin      (gm/100ml)	2.7	3	Slightly  Increased
Albumin : Globulin	1.7 : 1	1 : 1	Decreased

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Blood or Hematological changes during pregnancy

During pregnancy, there is increased vascularity of the enlarging uterus with the interposition of uteroplacental circulation.


Principal blood changes during pregnancy -


                                                 Non pregnant           Pregnancy             Changes
                                                                                near term

         Blood volume (ml.) -             4000                      5500                   + 30-40 %

       Plasma volume (ml.) -            2500                      3750                   + 40-50 %

      Red cell volume (ml.) -            1400                       1750                   + 20-30 %

    Total hemoglobin (gm) -             475                        560                     + 18-20 %

Hematocrit (whole body) -              38 %                      32 %                   Diminished


Important - 

• There is increase in plasma volume which reduce the viscosity of blood and improves capillary blood.
• As increase in plasma volume is greater than that of red blood cell mass, hemodilution occurs. It is characterized by a lowered RBC count and hemoglobin level.

Que.-  Why the high volume of blood is required in pregnancy ?

Ans.-  A higher circulating volume is required for the following functions -

• To provide extra blood flow for placental circulation.
• To supply the extra metabolic needs of the fetus.
• To provide extra perfusion of kidney and other organs.
• To compensate for blood loss at delivery.

Related  Articles :

• Plasma protein changes during pregnancy
• Diagnosis of pregnancy in first trimester
• Factors responsible for abortion
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Weight gain in pregnancy

In early weeks, the patient may loose weight because of nausea and vomiting. The weight gain is progressive until the last 1-2 week. 

The total weight gain during the course of pregnancy for a healthy woman is average 12 kg.

Reproductive weight gain - 6 kg
                Net weight gain - 6 kg


Reproductive weight gain -

   Fetus - 3.3 kg

   Placenta - 0.6 kg
   Liquor - 0.8 kg

   Uterus - 0.9 kg
   Breast - 0.4 kg

Cutaneous changes during pregnancy

The distribution of pigment changes in selective -

Face - (Chloasma gravidarum or pregnancy mask) -

• It is an extreme form of pigmentation around the cheek, forehead and around the eyes. Disappears spontaneously after the delivery.

Breast - 

• Increase size of breast becomes evident even in early weeks. This is due to marked hypertrophy and proliferation of ducts and alveoli. Vascularity is increased which results in appearance of bluish vein which running under skin. The nipples become larger, erectile and deeply pigmented. 
• About 5th month, a less pigmented area forms around the primary areola witch is known as secondary areola.

Abdomen -

• Linea nigra - It is brownish black pigmented area in the middle stretching from xiphisternum to pubic symphysis. Pigmentary changes are due to probably melanocyte stimulating hormone (MHS) from the anterior pituitary. Pigmentation disappear after delivery.
• Straie gravidarum - These are slightly depressed liner mark with varying length and width found in pregnancy. They are predominantly found in abdominal wall below the umbilicus, sometimes over the thigh and breast.

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