Anatomic changes Uterus weight from 70gm 1 kg Uterus volume from 10ml 5000 ml Supine hypotensive syndrome Acute hypotensive episode
Supine hypotensive syndrome Third trimeter 10~15% Compression of inferior vena cava & aorta Decrease venous return to heart Decrease uteroplacental perfusion and fetal distress
Prevention Left lateral decubitus position Elevation the right hip 10~12cm Sit up position
Physiologic changes Cardiovascular system Respiratory system Gastrointestinal system Renal system Hematological system
Cardiovascular system Cardiac output increase 40% Mean arterial BP decrease Total blood volume increase 40~50% (1500ml) 14th to 30th weeks heart rate increase 10 beats/min
Respiratory system Diaphragm is displaced upward 3~4cm & rib flare out with chest circumference of 5~7 cm Oxygen consumption increase 15~20 % Respiratory rate increase
Gastrointestinal system Increase gastric acid production Decrease gastric mobility Incompetence of gastroesophageal sphincter Esophageal reflux Pernicious vomiting Constipation
Renal system Increase GFR Increase renal plasma flow Urinary tract infection
Hematological system Plasma volume increase 40~70c.c./kg Red cell volume increase 25-30c.c./kg Hemoglobin & hematocrit volume decrease Plasma levels of factors VII, VIII, X and fibrinogen increase Fibrinolytic activity decrease
Psychological changes Hypersensitivity regarding her size & appearance Fear of pain, disability, death and for baby Fear of dental procedures Sedation empathy and reassurance Minimize disturbance interruption & noises & to adjust room temperature & to minimize possible irritability
Radiography High dose (over 250rads) prior to 16 wks Microcephaly Mental retardation Cataracts ( 白內障 ) Microphthalamia Growth retardation Spontaneous abortion High dose after 20 wks Hair loss Skin lesions Bone marrow suppression
Hazard from irradiation of embryo Death of embryo Birth of a deformed child Increase frequency of malignancy decrease in childhood e.g. leukemia
Hazard from irradiation of embryo 1 rad of utero radiation exposure has been estimated to be approximately 0.1% malignant disease A dental periapical film rad (0.1 mrad) Naturally occurring 1/2000
Radiography An adverse fetal effects is unlikely to result from exposure to less than 5 rads with lead apron in place the female gonadal dose from a single periapical radiographs is about 0.1 mrad.
Procedure in making radiographs for pregnancy patients Make only the film absolutely essential for diagnosing the conditions Use lead-shielding Use long cone Use proper collimation & shielding Limited to affected tooth Extra care should be used while taking essential films to eliminate the need for repeated exposure
Medication Local anesthesia Antibiotics Analgesics Corticosteroids Sedatives
Food and drug administration (F.D.A) classification system
Local anesthesia Local anesthesia are not teratogenic, and may administered to pregnancy patient is usual clinical doses. Large dose of prilocaine are know to cause methemoglobinemia ( 變性血紅素血症 ) which could cause maternal & fetal hypoxia.
Vasoconstrictors Local vasoconstriction Delay uptake from the site of injection Increase the effectiveness & duration There is no specific contraindication to these vasoconstrictors in a pregnant patient although it is prudent to use minimal effective dose.
Local anesthesia Convulsion in a sensitized mother could also exert a teratogenic effect second to hypoxia The need for careful Hx taking & for aspiration & slow injected technique is obvious.
Antibiotics Penicillin FDA B All trimester are safe No teratogenic Pass the placenta Inhibit cell wall synthesis
Tetracycline Contraindication Chelation with calcium & deposited in the skeleton of the fetus resulting in depression of bone growth Discoloration Maternal fatty liver degeneration FDA D
Chloramphenicol Bone marrow depression irreversible aplastic anemia agranulocytosis FDA C Gray-baby syndrome Contraindication
Aminoglycoside Ototoxicity Nephrotoxity FDA D
Analgesics Identify the cause of the pain Eliminate it rather than relying on symptomatic relief with analgesic medication
Acetaminophen No teratogenesis Most frequency used Analgesic and antipyretic but no anti- inflammation activity
Aspirin Oral clefts and other defects Intrauterin death,growth retardation,pulmonary hypertention Longer pregnancies & longer the average period of labor Tetralogy of Fallot (Raot, RVhyperatrophy,Vsep def,Pula.steno) Increase the risk of antepartum and postpartum hemorrhage.
NSAID Contraindication Inhibit synthesis of postaglandins. Constrict the ductus arteriosus & persistent pulmonary hypertension & increase mortality
Corticosteroid Cleft palate Inhibit brain growth Indicated only for treatment of severe systemic maternal illness (e.g. RA)