ateefa Al Dakhyel FRCSC, FACOG Assistant professor & consultant Obstetric & gynecology department Collage of medicine King Saud University

 Maternal physiologic adjustment to pregnancy are designed to support the requirements of fetal needs without affecting maternal well-being.  The normal values of several hematologic, biochemical, and physiologic indices during pregnancy differ markedly from those in the non pregnant range and also according to duration of pregnancy.

ALIMENTARY TRACT. STOMACH.  Tone and motility decreases because of the effect the PROGESTERONE hormone and emptying time of the stomach is prolonged  Gastro esophageal junction sphincter tone decreases leading to heart burns  Gastric acid secretion decreases and peptic ulcer disease improved!!

Small & large bowel  motility decrease and increases iron absorption.  Colon, there is decrease motility resulting in constipation,increase water and sodium absorption and dilatation of hemorrohdial veins.(40% have constipation) Liver  Signs of normal pregnancy that may mimic liver disease

 Spider angiomata and palmer erythema due to increase estrogen level.  Decrease albumin and increase alkaline phosphatase.  Nausea and vomiting usually in first trimester

Respiratory system.  Mechanical changes. -Subcostal angles transverse chest diameter, and chest circumference increases and the diaphragm level is pushed up.  Lung volume and pulmonary function. -Tidal volume increase inspiratory capacity increases, vital capacity decreases but RR little chaged

Skin  Vascular changes, due to estrogen.  Spider angiomata,palmer erythema.  Striae gravidarum (stretch marks)  Pigmentation changes,increases melanocyte- stimulating hormones which cause:darkening of nipples, areolae,umbilicus, axillae, perineum and linea nigra

 melasma or mask of pregnancy.  Pigmented navi  Mild hirsitusm then postpartum telogen effluvium.

Urinary system.  Anatomic changes.  Kidneys increase in both length and weight.  Renal pelvis increase resulting in physiological hydro nephrosis.  Right ureter is larger than the left causing hydroureter in the abdominal ureter.

 Increase risk of pyelonephritis and asymptomatic bacteriuria  Renal plasma flow, glomerular filtration rate and creatinine clearance are all increase more than 50%,  Blood urea creatinine and uric acid all decrease due to increase in intravascular volume.

 Glucosuria is common in normal pregnancy and has no correlation with blood sugar level.  Increase excretion of water soluble vitamin folate and vitamin B 12

Cardiovascular system.  There is a change in the position of the heart.  Normal changes in heart sound include.  Exaggerated splitting of S1  Gallop pulse in 90% of normal pregnancy  Systolic ejection murmur.

 EKG is unchanged except for left axis deviation.  Increase cardiac output by 40% due to increase in both stroke volume and heart rate (HR increase ~10bpm)  Cardiac output depends on maternal position,it is lowest when in supine position ( Supine hypotension syndrome)

 Blood pressure changes due to vasodilatation & intravascular volume increase.  There is a progressive decrease in both systolic and diastolic pressure mainly in mid trimester, after 24 weeks the pressure gradually increase and return to non pregnant level by term.  Central venous pressure remain unchanged.

Hematological changes.  Plasma volume increase % by term it begins by 10 weeks and plateaus at 30 weeks gestation most of increase is in 2ed trimester more increase in multiple pregnancy or larger fetuses.  Red blood cell increases by 30% at term.  Physiological anemia result because the plasma volume increases more than RBC. midpregnancy ~11.5 gm/dl(anemia<10.5) early & late ~ 12.3 gm/dl(anemia<11)

 White blood cell mostly PMN granulocytes increases progressively in pregnancy.  Platelets slightly decrease.  Coagulation system. Pregnancy is a hyper coagulable state. Fibrinogen increase by 50%. Factors V11,V111,1X,and X all increases

Iron metabolism.  Absorption depends on pregnancy state and bone marrow iron stores,40% absorption in the iron deficient state.  The total iron requirement is 1000 mg and the daily requirement is 3.5 mg.  Maternal iron deficiency does not affect fetal iron stores because of active iron transport across the placenta.

Endocrine and metabolic changes.  Thyroid gland.it increase in size.  Thyroid binding globulin increases as a result of estrogen stimulation of the liver.  The active unbound form remain unchanged or slightly decrease.  The following thyroid hormones do not cross the placenta T3, T4,and TSH, thyroid immunoglobulins crosses the placenta as well ass anti thyroid medication

Adrenal gland.  Total and free cortisol increase by two fold  Aldosterone secretion is markedly increase.  Deoxycortisone level increases.  Pancreas there hypertrophy and hyperplasia.  Fasting blood glucose is lower than in non pregnant state

placenta  Normal term placenta wt~ gm (~1/6 of fetal wt)  Placenta has 2 sides: maternal-facing- side has cotyledons fetal-facing-side covered by transparent amnion, chorion  Placenta hormones: hCG, hPL….  Uteroplacental blood flow ml/min in late pregnancy  Placenta connect to the fetus through 3BV

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