Updated: 12/11/2019

Reproductive Physiology

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  • A 27-year-old woman presents to her primary care physician due to missed menses. She reports to having a 28-day menstrual cycle with minimal variability, and her last menstrual period was 7 weeks ago. She reports morning sickness and is currently sexually active with one man and use condoms intermittently. Physical examination is unremarkable. A urine β-hCG test is positive. (Pregnancy)
  • Estrogen 
    • source
      • ovaries (17β-estradiol), placenta (estriol), and adipose (estrone)
    • ovarian synthesis
      • theca cells produce androgens secondary to luteinizing hormone (LH) stimulation
        • androgens diffuse to adjacent granulosa cells
      • granulosa cells, under follicle-stimulating hormone (FSH) stimulation, leads to
        • aromatase activity that results in
          • conversion of androgens to estrogens (17β-estradiol)
    • function
      • matures and maintains the fallopian tubes, uterus, cervix, and vagina
      • develops secondary sex characteristics
      • breast development
      • maintains pregnancy 
        • also decreases uterine threshold to contractile stimuli during pregnancy
      • increases mitotic activity of the endometrium
      • negative and positive feedback effects on FSH and LH secretion
  • Progesterone
    • source
      • corpus luteum, placenta, and adrenal cortex in women
    • function
      • maintains pregnancy
        • increases uterine threshold to contractile stimuli during pregnancy
      • breast development
      • negative feedback on FSH and LH secretion (in luteal phase)
      • uterine secretory activity maintenance in the luteal phase
  • Oogenesis
    • during fetal life 1° oocytes begin meiosis I
      • meiosis I is completed prior to ovulation
        • the oocytes are arrested in prophase I until ovulation occurs
    • oocytes are arrested in metaphase II until the oocyte becomes fertilized
Menstrual Cycle
  • Follicular phase (days 1-14)
    • a primordial follicle is formed
    • upregulation of LH and FSH receptors on theca and granulosa cells
      • estrogen results in
        • uterine proliferation
        • negative feedback on anterior pituitary leading to
          • LH and FSH levels
    • progesterone levels
  • Ovulation (day 14)
    • ovulation = menses - 14 days
    • secondary to estrogen-induced LH surge
    • cervical mucous is thin, clear, and profuse
      • secondary to estrogen levels
    • ferning on wet mount due to electrolyte content
    • anovulation can occur during the first few menstrual cycles due to an immature hypothalamic-pituitary-gonadal axis 
  • Luteal phase (days 14-28)
    • development of the corpus luteum which results in
      • estrogen and progesterone synthesis
    • endometrium has vascularity and secretory activity
    • basal body temperature due to
      • progesterone's effect on the hypothalamus
    • no fertilization leads to regression of the corpus luteum leading to
      • an abrupt of estradiol and progesterone
  • Menses (days 0-4)
    • estradiol and progesterone leads to
      • endometrial sloughing
  • Pathology
    • neonates may experience "menses" secondary to rapid withdrawal of maternal hormones
      • no diagnostic workup or treatment required
    • amenorrhea (primary and secondary)
    • dysmenorrhea
    • abnormal uterine bleeding
  • Fertilization
    • human chorionic gonadotropin (hCG) rescues the corpus luteum from regression which results in
      • continued progesterone secretion
  • Human placental lactogen (HPL)
    • insulin resistance which results in
      • glucose and amino acids to the fetus
  • Physiology
    • cardiovascular
      • systolic and diastolic blood pressures (BP) decline  
        • there is an cardiac output and heart rate
      • diastolic murmurs are never normal in pregnancy
    • hematologic
      • dilutional effect on hemoglobin (physiologic anemia) due to
        • increased plasma volume
      • hypercoagulable state
    • pulmonary
      • tidal volume and minute ventilation that results in
        • a respiratory alkalosis
          • kidneys bicarbonate loss to compensate

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Questions (3)
Lab Values
Blood, Plasma, Serum Reference Range
ALT 8-20 U/L
Amylase, serum 25-125 U/L
AST 8-20 U/L
Bilirubin, serum (adult) Total // Direct 0.1-1.0 mg/dL // 0.0-0.3 mg/dL
Calcium, serum (Ca2+) 8.4-10.2 mg/dL
Cholesterol, serum Rec: < 200 mg/dL
Cortisol, serum 0800 h: 5-23 μg/dL //1600 h:
3-15 μg/dL
2000 h: ≤ 50% of 0800 h
Creatine kinase, serum Male: 25-90 U/L
Female: 10-70 U/L
Creatinine, serum 0.6-1.2 mg/dL
Electrolytes, serum  
Sodium (Na+) 136-145 mEq/L
Chloride (Cl-) 95-105 mEq/L
Potassium (K+) 3.5-5.0 mEq/L
Bicarbonate (HCO3-) 22-28 mEq/L
Magnesium (Mg2+) 1.5-2.0 mEq/L
Estriol, total, serum (in pregnancy)  
24-28 wks // 32-36 wks 30-170 ng/mL // 60-280 ng/mL
28-32 wk // 36-40 wks 40-220 ng/mL // 80-350 ng/mL
Ferritin, serum Male: 15-200 ng/mL
Female: 12-150 ng/mL
Follicle-stimulating hormone, serum/plasma Male: 4-25 mIU/mL
Female: premenopause: 4-30 mIU/mL
midcycle peak: 10-90 mIU/mL
postmenopause: 40-250
pH 7.35-7.45
PCO2 33-45 mmHg
PO2 75-105 mmHg
Glucose, serum Fasting: 70-110 mg/dL
2-h postprandial:<120 mg/dL
Growth hormone - arginine stimulation Fasting: <5 ng/mL
Provocative stimuli: > 7ng/mL
Immunoglobulins, serum  
IgA 76-390 mg/dL
IgE 0-380 IU/mL
IgG 650-1500 mg/dL
IgM 40-345 mg/dL
Iron 50-170 μg/dL
Lactate dehydrogenase, serum 45-90 U/L
Luteinizing hormone, serum/plasma Male: 6-23 mIU/mL
Female: follicular phase: 5-30 mIU/mL
midcycle: 75-150 mIU/mL
postmenopause 30-200 mIU/mL
Osmolality, serum 275-295 mOsmol/kd H2O
Parathyroid hormone, serume, N-terminal 230-630 pg/mL
Phosphatase (alkaline), serum (p-NPP at 30° C) 20-70 U/L
Phosphorus (inorganic), serum 3.0-4.5 mg/dL
Prolactin, serum (hPRL) < 20 ng/mL
Proteins, serum  
Total (recumbent) 6.0-7.8 g/dL
Albumin 3.5-5.5 g/dL
Globulin 2.3-3.5 g/dL
Thyroid-stimulating hormone, serum or plasma .5-5.0 μU/mL
Thyroidal iodine (123I) uptake 8%-30% of administered dose/24h
Thyroxine (T4), serum 5-12 μg/dL
Triglycerides, serum 35-160 mg/dL
Triiodothyronine (T3), serum (RIA) 115-190 ng/dL
Triiodothyronine (T3) resin uptake 25%-35%
Urea nitrogen, serum 7-18 mg/dL
Uric acid, serum 3.0-8.2 mg/dL
Hematologic Reference Range
Bleeding time 2-7 minutes
Erythrocyte count Male: 4.3-5.9 million/mm3
Female: 3.5-5.5 million mm3
Erythrocyte sedimentation rate (Westergren) Male: 0-15 mm/h
Female: 0-20 mm/h
Hematocrit Male: 41%-53%
Female: 36%-46%
Hemoglobin A1c ≤ 6 %
Hemoglobin, blood Male: 13.5-17.5 g/dL
Female: 12.0-16.0 g/dL
Hemoglobin, plasma 1-4 mg/dL
Leukocyte count and differential  
Leukocyte count 4,500-11,000/mm3
Segmented neutrophils 54%-62%
Bands 3%-5%
Eosinophils 1%-3%
Basophils 0%-0.75%
Lymphocytes 25%-33%
Monocytes 3%-7%
Mean corpuscular hemoglobin 25.4-34.6 pg/cell
Mean corpuscular hemoglobin concentration 31%-36% Hb/cell
Mean corpuscular volume 80-100 μm3
Partial thromboplastin time (activated) 25-40 seconds
Platelet count 150,000-400,000/mm3
Prothrombin time 11-15 seconds
Reticulocyte count 0.5%-1.5% of red cells
Thrombin time < 2 seconds deviation from control
Plasma Male: 25-43 mL/kg
Female: 28-45 mL/kg
Red cell Male: 20-36 mL/kg
Female: 19-31 mL/kg
Cerebrospinal Fluid Reference Range
Cell count 0-5/mm3
Chloride 118-132 mEq/L
Gamma globulin 3%-12% total proteins
Glucose 40-70 mg/dL
Pressure 70-180 mm H2O
Proteins, total < 40 mg/dL
Sweat Reference Range
Chloride 0-35 mmol/L
Calcium 100-300 mg/24 h
Chloride Varies with intake
Creatinine clearance Male: 97-137 mL/min
Female: 88-128 mL/min
Estriol, total (in pregnancy)  
30 wks 6-18 mg/24 h
35 wks 9-28 mg/24 h
40 wks 13-42 mg/24 h
17-Hydroxycorticosteroids Male: 3.0-10.0 mg/24 h
Female: 2.0-8.0 mg/24 h
17-Ketosteroids, total Male: 8-20 mg/24 h
Female: 6-15 mg/24 h
Osmolality 50-1400 mOsmol/kg H2O
Oxalate 8-40 μg/mL
Potassium Varies with diet
Proteins, total < 150 mg/24 h
Sodium Varies with diet
Uric acid Varies with diet
Body Mass Index (BMI) Adult: 19-25 kg/m2

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(M2.GN.17.4752) A 24-year-old woman presents to her physician complaining of intermittent vaginal discharge. She has noticed this for the last 3 months and states that it looks “like egg white”. Although she does not recall a specific pattern to the discharge, she notes that it happens every few weeks or so. She has not noticed a significant odor to the discharge. The patient has regular periods every 28 days with mild cramping and increased fatigue for one day each cycle. Her last period was 2 weeks ago. She has a past medical history of a recent urinary tract infection, for which she received a course of ciprofloxacin. Six months ago, she started having intercourse with a new partner and has not been using barrier protection. At this visit, her temperature is 98.4°F (36.9°C), blood pressure is 124/76 mmHg, pulse is 70/min, and respirations are 14/min. The patient has a soft, nontender abdomen, and speculum exam reveals a clear, thin discharge in the vaginal vault. There is no adnexal or cervical motion tenderness, and the vulvar skin is without erythema or irritation. A wet mount of a vaginal swab is shown in Figure A. Which of the following is the underlying etiology of this patient’s presentation? Review Topic | Tested Concept

QID: 108725

Alteration of vaginal flora




Increased FSH levels




Increased estrogen levels




Sexually transmitted disease




Increased progesterone levels



L 2 D

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