Perubahan Fisiologi pada Kehamilan

Perubahan tubuh wanita pada kehamilan terutama genitalia eksterna dan interna serta payudara dipengaruhi oleh hormon somatotropin, estrogen dan progesteron.

UTERUS
  • Besar  uterus normal 30 gr, advokat, gepeng, telur ayam.
  • 8 minggu  : telur bebek.
  • 12 minggu : telur angsa, Fundus uteri teraba
  • 16 minggu : tinju dewasa
  • 20 minggu : Fundus uteri 1 jari bawah pusat
  • 24 minggu : Fundis uteri setinggi pusat
  • 28 minggu : Fundus uteri 3 jari diatas pusat.
  • Hipertropi dari ischmus menjadi  panjang dan lunak ( hegar sign ).
  • Pada triwulan terakhir ischmus ->  Segmen bawah rahim menjadi lebar dan tipis -> lingk. Retraksi fisiologis

Peningkatan Berat Badan (Weight Increase)

  • Total increase 12.5kg
  • Breasts – 1.5kg
  • Uterus – 0.5kg
  • Fetus and placenta 5kg
  • Fat storage subcutaneous tissues 4.5kg
  • Water and electrolytes 1/1.5kg

Serviks uteri

  • 10% otot polos dan sisanya kolagen
  • Estrogen menyebabkan hipervaskularisasi dan mengeluarkan cairan yang banyak
  • Portio primigravida bundar dan multigravida terbelah dua atau menganga.

Vagina dan vulva

  • Hipervascularisasi pada vagina dan vulva kebiruan (Chadwich Sign)

Mamma

  • Estrogen menyebabkan hipertrophi saluran.
  • Progesteron menyebabkan  sel asinus bertambah.
  • Somatomamotropin menyebabkan pertumbuhan asinus, produksi kasein, latalbumin dan laktoglobulin.
  • Papilla mamma membesar, tegak dan lebih hitam juga areola mamma.
  • 12 minggu -> colostrum.

Sirkulasi

  • Meningkat 25% terutama pada 32 minggu.
  • CO meningkat 40%.
  • Hemodilusi, peningkatan plasma melebihi eritrosit menyebabkan anemia fisiologis ( 16 minggu ).
  • Hemokonsentrasi terjadi post partum terutama pada hari ke 3 dan 5.

CARDIOVASCULAR

  • Plasma Volume increases from 2.6 litres to about 2.8 litres
  • Red Cell Mass increases from 1.4 litres
  • Haematocrit (percentage) falls from 35.0 to 30.0
  • Cardiac output increases by 40%
  • Heart rate increases by 10%
  • Stroke volume increases by 25%

Placental Architecture

  • Maternal and fetal blood do not mix:   “placental barrier”
  • Fetal blood flows through capillary networks within highly branched terminal chorionic villi
  • Maternal blood flows through intervillous space
  • Uterine arteriols bring blood in
  • Uterine venules drain blood

GASTRO-INTESTINAL TRACT

  • Changes are chiefly as a result of relaxation
  • Relaxation of oesophageal sphincter causes heartburn
  • Decreased gastric motility causes nausea
  • Decreased motility of large intestine causes constipation

RESPIRATORY

  • Meningkat 20 %.
  • Penekanan usus dan diafragma oleh uterus menyebabkan sesak nafas ( 32 minggu ).
  • Respiratoy rate is unchanged
  • Decreased resting lung volume
  • Tidal volume increased by 40%
  • Concentration of carbon dioxide decreased by 8%

ENDOCRINE SYSTEM

  • Progesterone produced by the corpus luteum
  • Estrogen produced by the ovaries
  • Cortisol produced by the maternal adrenals

PROGESTERONE

  • Reduces the smooth muscle tone
  • Reduces uterine tone
  • Reduces the vascular tone
  • Increases fat storage
  • Reduces overbreathing
  • Induces development of breasts

CORTISOL

  • increases blood sugar
  • modifies blood antibody activity

ESTROGEN

  • Estrone and estradiol increased 100 fold
  • Eestriol increased 1000 fold
  • Induces growth of uterus
  • Inhances breast development
  • Alters connective tissue – stretches cervix, relaxes joint capsules
  • Water retention
  • May reduce sodium secretion

HUMAN CHORIONIC GONADOTROPHIN (HCG)

  • Produced by trophoblast
  • Levels peak at 16 weeks
  • Required for early maintenance of the corpus luteum
  • Otherwise role unclear

RELAXIN

  • Produced by the corpus luteun
  • Highest levels in 3rd  trimester
  • May have a role in cervical ripening

ALDOSTERONE

  • Wholly derived from the maternal adrenals
  • Much increased in pregnancy
  • Promotes retention of sodium and water

HUMAN PLACENTAL LACTOGEN (HPL)

  • HPL rises steadily with placental growth
  • Lactogenic
  • Antagonistic to insulin

PITUITARY HORMONES

  • Maternal FSH and LH are supressed during pregnancy
  • Prolactin levels rise throughout
  • Lactation does not start until high prolactin levels after delivery with fallen oestrogen levels

THYROID FUNCTION

  • Thyroid increases in pregnancy to approximately twice its size
  • Oestrogen stimulates increased thyroxin-binding globulin
  • Free thyroxine levels remain normal

URINARY SYSTEM

  • Trimester I : BAK meningkat karena penekanan blast oleh uterus.
  • Trimester III : BAK meningkat karena penekanan kepala janin.
  • Poliuria karena filtrasi glomerulus meningkat 69%. Kidneys increase by 1cm in length
  • Ureters are dilated
  • Renal blood flow increases from 1.2 L/min – 1.5 L/min
  • GFR increases from 140ml – 170ml /min
  • Blood urea decreases from 4.3 to 3.l mmol/L

Kulit

  • Melanophore stimulating hormon ( MSH ) menyebabkan hiperpigmentasi.
  • Cloasma gravidarum ( dagu, pipi & hidung ).
  • Areola mamma.
  • Linea alba menjadi hitam ( Linea grisea ).
  • Kulit retak –retak dan kebiruan ( Striae lividae ) -> setelah partus menjadi putih ( Striae albican).

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