Normal Maternal Physiological Adaptations

Normal Maternal Physiological Adaptations In CO -> week 6 Inc. BV -> inc. preload Dec. SVR -> dec. afterload Inc HR -> 1 st trimester Dec SBP, DBP and MAP -> 1 st trimester Cardiovascular and hemodynamic changes CVR -> unchanged Dec uterine vascular tone Uterine artery dilation Inc in artery length and diameter -> by week 5 Size of uterine artery doubles by week 20 Inc cerebral flow Inc risk of aortic dissection Murmurs: Systolic ejection murmurs may appear due to increased flow; usually benign. Increased end diastolic LV volume The below changes cause -> compensated resp alkalosis, dec PCO2, inc PO2 Outward flaring of the ribs – early Diaphragm -> enlarged uterus -> pushed up from norm resting position Dec ERB and RV -> dec FRC Changes in VC and TLC are small non-significant Respiratory changes Inc resting minute ventilation Compensated resp alkalosis -> compensatory renal HCO3 excretion Maximal O2 consumption (VO2 max) -> preserved Upper resp tract mucosa -> hyperaemia, glandular hyperactivity, inc phagocytic activity and inc mucopolysaccharides 75% experience dyspnoea Inc blood volume Mile neutropenia Mild thrombocytopenia Inc procoagulant factors -> I, VII, VIII, IX, X, vWF Hematology changes Dec natural anticoagulants -> protein C &S, Antithrombin -> norm or slightly dec Factors that remain unchanged -> II, V, XI, XIII Diminished fibrinolysis Taste changes Nausea and vomit Hemodilution -> dec albumin Inc Sr total LDL cholesterol and triglycerides Inc ALP Dec GGT Dec gallbladder motility Inc bile lithogenicity GIT changes Inc GERD features Slight inc or normal amylase Acute pancreatitis is rare Bloating and constipation Faecal incontinence Haemorrhoids Changes to maternal gut microbiota Impact on dental caries is not clear Inc in kidney size -> by 1 to 1.5 cm Dilation of renal pelvis and proximal ureters -> hydronephrosis Due to progesterone In 80% of normal pregnancies Renal hemodynamic Vasodilation Inc arterial compliance Dec SVR Inc CO Small dec in BP Renal Inc GFR -> due to relaxin Dec in Sr urea and Cr -> more excreted in urine due to inc GFR Inc aldosterone and ADH Hyponatremia Proteinuria Glucosuria Hypouricemia Dec in Sr anion gap and albumin Ureter dilation Oedematous bladder mucosa Flaccid bladder -> vesicoureteral reflex Hyperpigmentation Due to inc estrogen and progesterone Melasma Nevi Vascular spiders Palmar erythema Varicosities Vascular tumours Skin Pyogenic granulomas Hemangiomas Angiolipomas Angiolymphoid hyperplasia with eosinophilia Striae gravidarum Skin tags Pruritus Weight gain and hormonal changes cause: Force against joints Exaggerated lordosis of lower back Joint laxity in ant. And post. Longitudinal ligaments of the lumbar spine -> inc risk of muscle strain Inc widening and inc mobility of the sacroiliac joints and pubic symphysis MSK Vaginal lengthening Genital hiatal widening Posterior vaginal relaxation Significant inc in ant tilt of pelvis with inc use of hip extensors abductors and ankle plantar flexor muscles Fluid retention -> compression of vulnerable structures e.g. median nerve Ligamentous laxity -> affects stability of all weight bearing joints from pelvis to foot Anatomical changes in pregnancy Placenta development Abdominal extension Weight gain Breast enlargement and tenderness Some postural changes Uterus changes position First trimester: Begins as a pelvic organ -> sits deep behind pubic bone Wk 12 -> rises out of the pelvis -> more abdominal Second trimester: Grows upward and forward -> level of umbilics -> wk 20 Displaces abdominal organs -> intestines pushed laterally and upward Uterus rotates slightly to the right -> dextro-rotation Due to the sigmoid colon being on the left Third trimester Uterus reaches maximal height -> extend to xiphoid process Becomes dominant abdominal organ -> presses against diaphragm -> dyspnoea and reflux