CHAPTER 30
Obstetrics and Gynecology
Test Taking Tip
Remember to review the management of tubo-ovarian abscesses and the physiologic changes of the pregnant patient during each of the trimesters.
FIGURE 30-1. The muscles and vasculature of the pelvis. (Reproduced from Brunicardi FC, Andersen DK, Billiar TR, et al. Schwartz’s Principles of Surgery. 9th ed. http://www.accessmedicine.com. Copyright © The McGraw-Hill Companies, Inc. All rights reserved.)
ANATOMY
What are the branches of the internal iliac artery (hypogastric)?
Posterior division: Iliolumbar, lateral sacral, superior gluteal Anterior division: Obturator, internal pudendal, inferior gluteal, umbilical, middle vesicle, inferior vesicle, middle hemorrhoidal, uterine, vaginal
Arterial supply to the uterus:
Uterine artery from the hypogastric and ovarian arteries directly from the aorta
Right ovarian vein originates from:
Inferior vena cava
Left ovarian vein originates from:
Left renal vein
Upper: cervical branch of the uterine artery
Middle: inferior vesical
Lower: internal pudendal and middle hemorrhoidal
The major arterial supply to the cervix is located:
In the lateral cervical walls at the 3 and 9 o’clock positions
The external pudendal artery supply:
The rectum, labia, clitoris, perineum
Artery that supplies the round ligament:
Sampson
Inferior epigastric artery and vein originates from:
External iliac artery and external iliac vein, respectively
Levator ani complex:
Iliococcygeus, pubococcygeus, puborectalis
Boundaries of the femoral triangle:
Sartorius, adductor longus muscle, and inguinal ligament
Floor of the femoral triangle is formed by:
Iliopsoas, pectineus, and adductor longus
FIGURE 30-2. The avascular spaces of the female pelvis. (Reproduced from Brunicardi FC, Andersen DK, Billiar TR, et al. Schwartz’s Principles of Surgery. 9th ed. http://www.accessmedicine.com. Copyright © The McGraw-Hill Companies, Inc. All rights reserved.)
Space of Retzius:
The area between the bladder and the symphysis pubis, bounded laterally by the obliterated hypogastric arteries
Cul-de-sac of Douglas:
Also known as the rectouterine pouch or fold and is located anterior to the rectum, separating the uterus from the large intestine
Boundaries of the paravesical space:
Anterior: pubic symphysis
Posterior: cardinal ligament
Medial: superior vesical artery
Lateral: obturator internus muscle
Boundaries of the pararectal space:
Anterior: cardinal ligament
Posterior: sacrum
Medial: rectum
Lateral: iliac vessels
Anatomic relationship between the uterine artery and the ureter:
At approximately 2 cm from the cervix, the uterine artery crosses above and in front of the ureter.
Support of the uterus:
The cardinal and uterosacral ligaments
Vaginal lymphatics:
Upper third: Iliac
Middle third: hypogastric
Lower third: inguinal
Aorta lies at this spinal level:
L4
Innervation to the uterus:
Hypogastric plexus by sympathetic merging at Frankenhauser plexus (uterovaginal plexus) Pain sensory to T11 to 12
Sensory innervation of the vagina:
Pudendal nerve (S2–S4)
Obturator nerve:
Sensory and motor to the medial thigh
Sciatic nerve:
L4 to S2; passing through the greater sciatic foramen to supplying the muscles of lateral leg and foot
PHYSIOLOGY
Increases in pregnancy:
GFR by 50%: 90 mL/min prepregnancy versus 125 mL/min pregnancy
Total T4
Total T3
PTH
Prolactin
Plasma fibrinogen: 300 mg/dL prepregnancy versus 600 mg/dL pregnancy
ESR
TBG: thyroxine-binding globulin
Cholesterol
Heart rate: Increased 10 to 15 bpm
Cardiac output: 1.5 mL/min more than prepregnant average
Prostacyclin
Thromboxane
Plasma volume
Red cell volume
Alkaline phoshatase
Progesterone
Estradiol
Decreases in pregnancy:
Total serum calcium
Albumin (decrease by 30%)
BUN and creatinine: due to increase in GFR
Hgb and Hct
Factor XI
Factor XIII
TSH
Systemic vascular resistance
pCO2: 35 to 40 mm Hg prepregnant to 28 to 30 mm Hg pregnant
Respiratory volume
Antithrombin III (anti-factor Xa)
Anticoagulant protein S
Cross the placenta:
Propylthiouracil, TRH, iodine, magnesium sulfate, IgG, propanolol, warfarin
Does not cross the placenta:
T3, T4, TSH, insulin, glucagon, heparin, prednisone
hCG peaks at:
8 to 10 weeks gestation
Average weight gained in pregnancy:
25 lb
Average weight and volume of non-pregnant uterus:
40 to 70 g and 10 mL
Average weight and volume of pregnant uterus:
1100 to 1200 g and 5000 mL
What supports pregnancy during the first 14 weeks of pregnancy prior to the development of the placenta?
The corpus luteum, which secretes progesterone
Gestational age at which the uterus rises out of the pelvis:
12 weeks gestation
In late pregnancy blood flow rate to the uterus:
450 to 650 mL/min
Percentage of uterine blood flow direct to the placenta at term:
80% to 90%
Pulmonary function in pregnancy:
Increase: Tidal volume, inspiratory capacity, minute ventilation, minute oxygen uptake
Decrease: Functional residual capacity (by 15%), residual volume, expiratory reserve volume
Unchanged: Maximum breathing capacity, forced expiratory volume (FEV1)
Physiologic hydronephrosis of pregnancy resolve in:
12 to 16 weeks postpartum
Gastric acid production and gastric emptying:
Increased and decreased, respectively, in pregnancy
Two GI disorders in third trimester pregnancy:
Acute fatty liver of pregnancy and cholestasis of pregnancy
OBSTETRICAL CONDITIONS AND COMPLICATIONS
Incidence of hypertensive disease in pregnancy:
12% to 22%
New onset hypertension and proteinuria after 20 weeks gestation in a previously normotensive woman:
Preeclampsia
Criteria for diagnosis of preeclampsia:
Mild: BP 140/90, 6 hours apart plus at least 1+ protein on urine dip or >300 mg of protein on 24-hour urine
Severe: BP 160/110 6 hours apart plus at least 3+ protein on urine dip or 5000 mg of protein on 24-hour urine protein
New-onset hypertension without proteinuria after 20 weeks gestation in a previously normotensive woman:
Gestational hypertension
New-onset grand mal seizure in woman with preeclampsia:
Eclampsia
Treatment of preecalmpsia:
Magnesium sulfate for seizure prophylaxis, labetalol and hydralazine for BP control and expedient delivery
HELLP syndrome is characterized by: