PHYSIOLOGICAL CHANGES DURING PREGNANCY

⁷5 pp 0PHYSIOLOGICAL CHANGES DURING PREGNANCY

• Physiological changes during pregnancy are the normal changes in woman’s body  that occur to support the growth and development of the fetus .
• THERE ARE MANY  PHYSIOLOGICAL CHANGES OCCUR DURING PREGNANCY IN ALL SYSTEM OF THE BODY
• 1-Changes in Reproductive system
• 2- Changes in cardiova
• 3- Changes in Urinary system
• 4- Changes in Gastrointestinal system 
• 5-Changes in Endocrine system
• 1-PHYSIOLOGICAL CHANGES  IN PREGNANCY OF REPRODUCTIVE SYSTEM
• Uterus
• Cervix
• Vagina

        CHANGES IN VULVA

• Vulva becomes swollen (edematous) during pregnancy.
• Blood supply increases, so it looks more vascular.
  .
• Superficial veins become enlarged (varicosities).
  These varicose veins are common in multiparous women.
• Labia minora become darker due to pigmentation.
  Labia minora increase in size (hypertrophy).
  All these changes are normal during pregnancy.
• CHANGES  OCCUR iN UTERUS  DURING PREGNANCY
• 1-WEIGHT –
• In non pregnant state the weight of the uterus is 50 gm but after pregnancy it is 20 times increase and teached  to 1000 gms .
• 2-VOLUME –
• In non pregnant state the volume of the uterus is -10 ml but after pregnancy it is increased to around  5 litres
• 3-SHAPE –
• the uterus shape change during pregnancy. Elongated to oval by second month of pregnancy
• Round shape of uterus ( by midgestation)
• Oval to elongated shape at term
• 4_CHANGES IN MUSCLE LAYER OF UTERUS
• Hyperplasia and hypertrophy occur in muscle fibers during pregnancy.
• 1-Outer longitudinal layer
  Location: Outer surface of the uterus
  Muscle fibers: Run lengthwise (top to bottom)
  Function:
  Helps in pushing the fetus downward during labor
  Contributes to contractions
  2. Middle vascular layer -the middle layer arranged in criss-  -cross pattern.and give the figure of ‘8’ form .(What “figure of 8” means in the uterus?
  The circular muscle fibers of the uterus wrap around the blood vessels and cervix in a special way.
  When you look from above, their arrangement looks like the number 8 )
  This is why it is called figure-of-8 fibers
• This middle layer muscle fibres called as living ligature
• A ligature is a surgical tie used to stop bleeding.
  These muscle fibers naturally squeeze blood vessels after childbirth.
  So they act like a living, natural tie (ligature) to prevent postpartum bleeding.
• Location: Middle layer of the myometrium
  Muscle fibers:
  Special feature: Rich in blood vessels
  Function:
  Provides blood supply to the uterus and placenta
  Helps in strong contractions during labor
  Important for controlling bleeding after delivery
  3. Inner circular layer
• Location: Just beneath the endometrium (inner lining)
• Muscle fibers: Run around the uterine cavity (circular)
• Function:
• Helps in closing the uterine cavity
• Supports placental attachment
• Plays a role in labor contractions and involution
• CHANGES IN POSITION OF THE UTERUS 
• During early pregnancy (up to 8 weeks), the uterus is anteverted and this position. The enlarged uterus lies on the urinary bladder, making it unable to fill properly.
• This leads to frequency of micturition (frequent urination).
• After 8 weeks, the uterus rises upward and becomes more erect.
• The long axis of the uterus aligns with the axis of the pelvic inlet.
• Near term, in multipara (women with previous births), due to lax abdominal muscles, there is more anteversion.
• In primigravida (first pregnancy), strong abdominal muscles hold the uterus firmly against the maternal spine.
  Thus, the position of the uterus changes throughout pregnancy depending on growth and muscle tone of the uterus.
• As the uterus grows, it moves upward into the abdominal cavity
•  While growing, it rotates slightly to the right side (called dextro-rotation).
•  This happens because the rectosigmoid colon is present on the left side.
•  Due to this, the uterus cannot expand on the left, so it shifts to the right.
• The front (anterior surface) of the uterus turns toward the right side.
• The left cornu of the uterus comes closer to the abdominal wall.
• As a result, the cervix shifts toward the left side (called levorotation).
•  This brings the cervix closer to the left ureter.

• CHANGES IN SHAPE OF THE UTERUS 

•  In the non-pregnant state, the uterus has a pyriform (pear) shape.
•  In early pregnancy, this pyriform shape is maintained.
•  By around 12 weeks, the uterus becomes globular (round).
• This happens due to uniform enlargement of the uterus.
•  As pregnancy progresses, the uterus continues to increase in size.
•  By around 20 weeks, it again becomes pyriform or ovoid (oval shape).
•  In late pregnancy (after 36 weeks), the uterus becomes more spherical (rounded).
• These shape changes occur due to growth of fetus and stretching of uterine muscles.

• VASCULAR SYSTEM CHANGES IN UTEROUS 

• In the non-pregnant state, the uterus receives blood mainly from the uterine artery and less from the ovarian artery.
• n pregnancy, both uterine and ovarian arteries supply equal amount of blood.
•  The arteries become spiral in shape, reaching
• maximum spiraling at about 20 weeks.
• After 20 weeks, these arteries straighten out.
  The uterine artery diameter doubles and blood flow increases about 8 times.
• This increase is due to hormones like estrogen and progesterone.
•  The veins become dilated and valveless, allowing easy blood flow.
•  Many new lymphatic channels develop to support increased circulation.
• These vascular changes are maximum at the placental site, and the uterus enlarges unevenly, with fundus growing more than the body.
• BRAXTON -HICKS CONTRACTION 
• Braxton Hicks contractions are mild uterine contractions that occur during pregnancy.
• They are named after John Braxton Hicks, who first described them.
• These contractions start very early in pregnancy and happen naturally.
• They can be felt as the uterus becoming hard and then soft again.
• They are irregular, infrequent, and painless.
• They do not cause opening (dilatation) of the cervix.
• Most women do not notice them in early pregnancy.
  Near term, they become more frequent and slightly uncomfortable.
• Finally, they change into true painful labour contractions.
• CHANGES IN LENGTH OF THE UTERUS –
• Before pregnancy the length of the uteus is 7.5cm

After pregnancy the length of the uterus increases to 35 cm

• CHANGES IN BREADTH OF THE UTERUS
• Breath increases from 5cm to 22.5cm
• CHANGES IN THICKNESS OF UTERUS 
• Thickness increases from 2.5cm to 20cm
• CHANGES IN ISTHMUS
• Cervix and isthmus form lower uterine segment.it dilates during last trimester measures 7.5cm to 10 cm in length
• CHANGES IN CERVIX
• Cervical changes occur early in pregnancy due to hormones.
• The tissues (stroma) of the cervix increase in number and size (hyperplasia and hypertrophy).
• More fluid collects in and between these tissues, making it soft.
• Blood supply (vascularity) increases, especially below the surface layer.
• This causes a bluish color of the cervix.
• The glands in the cervix also grow and become larger.
• All these changes make the cervix very soft, called Goodell’s sign.
• This softening starts as early as 6 weeks of pregnancy.
• It helps in early diagnosis and makes cervical dilatation easier during labour.
• Cervical secretion –
• During pregnancy, the cervix produces more mucus (secretion).
• This secretion becomes thick, sticky, and increased in amount.
• It is called physiological leucorrhoea of pregnancy (normal discharge).
• This happens mainly due to the hormone progesterone.
• The mucus contains protective substances like immunoglobulins and cytokines.
• It helps to protect the uterus from infection.
  The thick mucus forms a plug in the cervical canal (mucus plug).
• This plug seals the uterus and protects the baby.
  Under microscope, the mucus shows changes due to progesterone effect.
• The cervix does not change in length but becomes thick and soft.
• In early pregnancy, the cervix is directed backward (posterior).
• After the fetal head engages, it becomes aligned with the vagina.
• The relation of the cervix with surrounding structures remains unchanged.
• The isthmus starts unfolding from 12 weeks of pregnancy.
• It helps in forming the lower uterine segment.
  In primigravida, cervix becomes thin (effacement) near term.
• In multipara, the cervix may be slightly dilated before labor.
• CHANGES I VAGINA
• In early pregnancy increased  blood circulation to the vagina so that the color form light pink to purple blue which is known as ‘chadwick’s sign
• CHANGES IN OVARIES
• The corpus luteum grows and works actively in early pregnancy.
• It reaches its maximum size around 8 weeks (about 2.5 cm) and may look cystic.
• Its color changes from bright to yellow, then becomes pale later.
• After some time, it starts shrinking as placental hormones take over.
• This happens due to decreased human chorionic gonadotropin (hCG) from the placenta.
  Around 12 weeks, it undergoes degeneration and may become calcified by term.
• It produces estrogen and progesterone to support early pregnancy.
• These hormones maintain the uterine lining (decidua) and prevent new ovulation.
  So, both ovarian and uterine cycles stop during pregnancy, and sometimes a luteoma (ovarian enlargement) can occur.
• Decidual reaction means the ovary shows temporary changes during pregnancy.
  Because of high pregnancy hormones,
• some cells on the surface of the ovary change into special pregnancy cells called decidual cells.
• This change is called metaplasia, which means one type of cell changes into another type.
• These decidual cells appear in patchy layers on the ovary.
• The same hormones also affect some immature or undeveloped follicles in the ovary.
• These follicles may change into structures similar to the corpus luteum, a process called luteinization.
• All these changes are normal in pregnancy and help the body support the developing baby 
• CHANGES IN FALLOPIAN TUBE
• During pregnancy, the uterus grows upward, especially the fundus (top part).
• Because of this, the fallopian tube is lifted up and becomes almost vertical.
• The fimbrial end is held in position by the infundibulopelvic ligament.
• The tube is attached to the uterus slightly lower due to the large growth of the fundus.
• Its total length increases a little during pregnancy.
• The tube becomes congested (more blood flow occurs).
• The muscle layer of the tube becomes thicker (hypertrophy).
• The inner lining (epithelium) becomes flat.
  Some areas also show decidual reaction

 

 

---

          CHANGES  IN  BREAST

• Breast changes in pregnancy are more noticeable in primigravida (first pregnancy).
  
• The breasts increase in size early in pregnancy.
  This happens due to growth of ducts and alveoli (milk-producing parts).
  
• The connective tissue also becomes thicker (hypertrophy).
  
• Myoepithelial cells increase, helping in milk ejection later.
  
• Blood supply increases, so veins (called Louis veins) become visible under the skin.
  
• The axillary tail of the breast enlarges and may become painful.
  
• Skin stretching may cause marks or irritation (striae). 

        NIPPLES AND AREOLA 

 

1. During pregnancy, the nipples become larger, erect, and darker (pigmented)
2. Small glands around the areola (5–15 in number) become enlarged.
3. These glands are called Montgomery’s tubercles.
4. They were not visible before pregnancy but now become prominent.
5. They are present around the nipple.
6. Their secretion keeps the nipple soft, moist, and healthy.
7. In the second trimester, another lightly pigmented outer area appears.
8. This is called the secondary areola.

      SECRETION

• Colostrum (first milk) can be squeezed from the breast from about 12 weeks of pregnancy.
• At first, it is clear and sticky.
  By around 16 weeks, it becomes thick and yellowish.
• Colostrum is the early milk produced before actual breastfeeding starts.
• If a woman who has never breastfed shows breast secretion, it is a sign of pregnancy.
• In later months, more colostrum can be expressed from the nipple.
• This is a normal change during pregnancy.
  It prepares the breast for feeding the baby after birth.

         WEIGHT GAIN  DURING PREGNANCY

• Total weight gain during pregnancy is -12 kg

          REPRODUCTIVE WEIGHT GAIN 

• ,- Fetus – 3.3 kg
• 2- placenta -0.6 kg ( 600 gms )
• 3 – Liquor -0.8 kg ( 800 gns)
• 4-Uterus -0.9 kg -900 gms
• 5- Breast – 0.4 kg (400 gms)

        NET  maternal weight gain

• 1- Increase in blood  volume -1.3 kg
• 2-Accumulation of fat and protein- 3.5 kg
• 3-Increase extracellular fluid -—1.2 kg

 

        CUTANEOUS CHANGES DURING PREGNANCY

• 1-Chloasma gravidarum (in pregnancy)
• It is also called the “mask of pregnancy.”
• It is a dark pigmentation (brown patches) on the face.
• Common sites: cheeks, forehead, nose, and chin.
  Caused by increased hormones (estrogen & progesterone).
• More common in pregnant women with sun exposure.
• It is harmless (no danger to mother or baby).
  It may increase during pregnancy and become more visible.
• Usually fades or disappears after delivery

       2-LINEA NIGRA

 

• Linea nigra is a brownish-black line in the middle of the abdomen.
• It extends from the chest (sternum) to the pubic area (symphysis pubis).
• It occurs due to increased pigmentation during pregnancy.
• Main cause is melanocyte stimulating hormone (MSH).
• Estrogen and progesterone also help in this change.
• Similar pigmentation can be seen in women taking oral contraceptive pills.
• It is a normal change in pregnancy.
• The pigmentation usually disappears after delivery
• STRIAE GRAVIDARUM  

 

• Striae gravidarum are slightly depressed (sunken) stretch marks on the skin.
• They vary in length and width.
  Commonly seen on abdomen (below umbilicus), thighs, and breasts.
• They occur due to stretching and tearing of deeper skin layer (dermis).
• At first, they appear pink or reddish.
  After delivery, blood vessels shrink and marks become white, shiny (striae alba).
• Hormones like aldosterone and skin stretching both cause them.
• Controlled weight gain and oil massage (like olive oil) may help reduce them.
• They can also occur in obesity, generalized edema, and Cushing syndrome.
• They are normal and harmless in pregnancy.

        Vascular spider (Spider angioma)

• It is a small red spot with tiny blood vessels spreading out like a spider.
• Found on face, neck, chest, and arms.Caused by increased estrogen hormone in pregnancy.When pressed, it may fade and then refill with blood.
• It is harmless and normal in pregnancy.
• Usually disappears after delivery.

       Palmar erythema

 

 

• It means redness of the palms (hands).
  Seen mainly on thumb and little finger areas.
• Caused by increased blood flow and estrogen.
• Palms feel warm and look red.
• It is not painful and harmless.
• usually goes away after delivery.
• Hematological changes during pregnancy 
• Blood volume is markedly raised during pregnancy
• The increase of blood volume starts from 6th week after that it increases rapidly.
• It reaches a maximum increase of about 40–50% compared to non-pregnant level.
• This maximum level is reached around 30–32 weeks of pregnancy.
• After that, the blood volume remains almost the same (static) till delivery (term).
• PLASMA VOLUME 
• Plasma volume also starts to increase by 6 weeks .
• It increases gradually and reach maximum around 30 weeks of gestation.
• Plasma volume increases more than RBCs
  Causes hemodilution
  Leads to physiological anemia of pregnancy
• Total plasma volume increases to the extent of 1.25 litres.
• The plasma volume increase is greater in multigravida.multiple pregnancy and large baby

         CHANGES IN RBCs AND HAEMOGLOBIN 

• .RBC mass increases by about 20–30%
• Total increase in RBC volume is about 350 ml
• This increase is due to higher oxygen demand during pregnancy
• RBC mass starts increasing from about 10 weeks
• It continues to increase till term (no plateau)
• Iron supplementation increases RBC mass up to 30%
• Reticulocyte count increases by about 2%
• Erythropoietin level increases and stimulates RBC production 
• Plasma increases more than RBCs during pregnancy
• This causes hemodilution (dilution of blood)
• Hematocrit level decreases
• Total hemoglobin mass increases by 18–20%
  But hemoglobin concentration appears decreased
  At term, hemoglobin falls by about 2 g/dL
• Number of RBCs decreases by 15–20% (relative fall)
  After delivery, excess hemoglobin is broken down
  Released iron is stored in the body