2. Pregnancy and Maternal Physiologic Adaptations to Pregnancy

Question 1

Name symptoms of pregnancy (5)

Answer 1

• amenorrhea
• nausea and/or vomiting
• breast tenderness
• urinary frequency
• fatigue

Question 2

Describe: GTPAL

Answer 2

• Gravidity (G)
  
  • G: total number of pregnancies of any gestation (multiple gestation=one pregnancy)
  • includes current pregnancy, abortions, ectopic pregnancies, and hydatidiform moles
• Parity (TPAL)
  
  • T: number of term deliveries (>37 wk)
  • P: number of premature deliveries (20-36+6 wk)
  • A: number of abortions (ending <20 wk)
    
    • induced (therapeutic) and spontaneous (miscarriage)
  • L: number of living children

Question 3

Name physical signs of pregnancy (5)

Answer 3

• uterine enlargement
• breast engorgement, areola darkening, and prominent vascular patterns
• Goodell’s sign: softening of the cervix (4-6 wk)
• Chadwick’s sign: bluish discolouration of the cervix and vagina due to pelvic vasculature engorgement (6 wk)
• Hegar’s sign: softening of the cervical isthmus (6-8 wk)

Question 4

Describe investigation of pregnancy (2)

Answer 4

• β-hCG: peptide hormone composed of α and β subunits produced by placental trophoblastic cells – maintains the corpus luteum during pregnancy
  
  • positive in serum 9 d post-conception, positive in urine 28 d after 1st day of LMP
  • plasma levels usually double every 1.4-2.0 d, peak at 8-12 wk, then fall, but continue to be measurable until delivery
• U/S
  
  • transvaginal and transabdominal

Question 5

β-hCGvels less than expected suggest what? (4)

Answer 5

• ectopic pregnancy
• abortion
• inaccurate dates
• or some normal pregnancies

Question 6

β-hCGvels greater than expected suggest what? (4)

Answer 6

• multiple gestation
• molar pregnancy
• Trisomy 21
• inaccurate dates

Question 7

What do you see on transvaginal U/S for pregnancies? (3)

Answer 7

• 5 wk GA: gestational sac visible
• 6 wk GA: fetal pole visible
• 7-8 wk GA: fetal heart activity visible

Question 8

What do you see on transabdominal U/S for pregnancies? (1)

Answer 8

• 6-8 wk GA: intrauterine pregnancy visible

Question 9

Describe: β-hCG Rule of 10s (3)

Answer 9

• 10 IU at time of missed menses
• 100,000 IU at 10 wk (peak)
• 10,000 IU at term

Question 10

Describe: Trimesters (4)

Answer 10

• T1 (first trimester): 1-14 wk
• T2 (second trimester): 14-28 wk
• T3 (third trimester): 28-42 wk
• Normal pregnancy term: 37-42 wk

Question 11

Name physiologic Changes During Pregnancy: Skin (6)

Answer 11

• Increased pigmentation of perineum and areola
• chloasma (pigmentation changes under eyes and on bridge of nose)
• linea nigra (midline abdominal pigmentation)
• spider angiomas
• palmar erythema due to increased estrogen
• and striae gravidarum due to connective tissue changes

Question 12

Name physiologic Changes During Pregnancy: Cardiovascular (4)

Answer 12

• Hyper-dynamic circulation
• Increased cardiac output, heart rate, and blood volume
• Decreased blood pressure: decreased PVR and decreased venous return from enlarging uterus compressing IVC and pelvic veins
• Increased venous pressure leads to risk of varicose veins, hemorrhoids, and leg edema

Question 13

Name physiologic Changes During Pregnancy: Hematologic (3)

Answer 13

• Hemodilution causes physiologic anemia and apparent decrease in hemoglobin and hematocrit Increased leukocyte count but impaired function leads to improvement in some autoimmune diseases
• Gestational thrombocytopenia: mild (platelets >70,000/µL) and asymptomatic, normalizes within 2-12 wk following delivery
• Hypercoagulable state: increased risk of DVT and PE but also decreased bleeding at delivery

Question 14

Name physiologic Changes During Pregnancy: Respiratory (4)

Answer 14

• Increased incidence of nasal congestion
• Increased O₂ consumption to meet increased metabolic requirements
• Elevated diaphragm (i.e. appears more “barrel-chested”)
• Increased minute ventilation leads to decreased CO₂ resulting in mild respiratory alkalosis that helps CO2 diffuse across the placenta from fetal to maternal circulation

Question 15

Name physiologic Changes During Pregnancy: Gastrointestinal (3)

Answer 15

• GERD due to increased intra-abdominal pressure and progesterone (causing decreased sphincter tone and delayed gastric emptying)
• Increased incidence of gallstones due to progesterone causing increased gallbladder stasis
• Constipation due to progesterone causing decreased GI motility and hemorrhoids as a result of constipation and increased intra-abdominal pressure

Question 16

Name physiologic Changes During Pregnancy: Genitourinary (5)

Answer 16

• Increased urinary frequency due to increased total urinary output
• Increased incidence of UTI and pyelonephritis due to urinary stasis
• Glycosuria that can be physiologic especially in the T3; consider testing for GDM if noted in first 2 trimesters
• Ureters and renal pelvis dilation (R>L) due to progesterone-induced smooth muscle relaxation and uterine enlargement
• Increased CO and thus increased GFR leads to decreased creatinine (normal in pregnancy 35-44 mmol/L), uric acid, and BUN

Question 17

Name physiologic Changes During Pregnancy: Neurologic (1)

Answer 17

Increased incidence of carpal tunnel syndrome and Bell’s palsy

Question 18

Name physiologic Changes During Pregnancy: Endocrine (5)

Answer 18

• Thyroid: moderate enlargement (not clinically detectable) and increased basal metabolic rate Increased total thyroxine and thyroxine binding globulin (TBG)
• Normal free thyroxine index and FSH levels
• Adrenal: increased maternal cortisol throughout pregnancy (total and free)
• Calcium: decreased total maternal Ca2+ due to decreased albumin
• Free ionized Ca2+ (i.e. active) proportion remains the same due to parathyroid hormone (PTH), resulting in increased bone resorption and gut absorption, and increased bone turnover (but no loss of bone density due to estrogen inhibition)