Stats September 13, 2006

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					Stats: September 13, 2006
OB Case: Shapiro – Arcuate Uterus/C-section
Questioner: B. Trivax

   1. Define “arcuate uterus”.

      Mullerian duct anomalies are categorized into 7 classes according to the
      American Fertility Society (AFS) Classification Scheme (1988). Class VI relates
      to the arcuate uterus. It is defined as having a single uterine cavity with a convex
      or flat uterine fundus and an endometrial cavity demonstrating a small fundal cleft
      or impression between 1-1.5cm. The outer contour of the uterus is convex or flat.
      The arcuate uterus is usually considered a normal variant since it is not
      significantly associated with the increased risks of pregnancy loss and other
      complications found in other subtypes.

   2. What are the important differences between an arcuate uterus and a septate

      A septate uterus (Class V) results from failure of resorption of the septum
      between the two uterine horns. In other words, it arises from a defect in
      canalization or resorption of the midline septum between the two mullerian ducts.
      The degree of septation varies from a small midline septum to total failure in
      resorption resulting in a septate uterus with a longitudinal vaginal septum. Partial
      and complete uterine septa are defined by the proximity of the septum to the
      internal os. It is important to note that the presence or absence of a vaginal
      septum is not relevant to the classification. The uterine fundus is typically convex
      but can be flat or slightly concave with a <1 cm fundal cleft. Women with septate
      uterus have the highest incidence of reproductive complications. Differentiation
      between a septate and a bicornuate uterus is important because septate uteri are
      treated using transvaginal hysteroscopic resection of the septum, while if surgery
      is indicated for the bicornuate uterus (Class IV), an abdominal approach is
      required to perform metroplasty.
3. There are three types of breech presentation. Define each one and include its
   percentage of presentation at term. Do you believe the arcuate uterus led to the
   breech presentation of this baby?

       a. Frank breech (50-70%) refers to a fetus with both hips flexed and both
           knees extended so its feet are near its head
       b. Complete breech (5-10%) refers to a fetus with both hips and both knees
           flexed. The feet are opposite the fetal trunk rather than the head, but do
           not present in advance of the buttocks.
       c. Footling or incomplete breech (10-40%) refers to a fetus with one or both
           hips or one or both knees not flexed. As a result, one or both feet present
           before the buttocks.
   Fetal malpresentation is often associated with abnormalities of the uterus, this
   includes altered intrauterine contour or volume as seen in bicornuate or septate
   uterus---not an arcuate uterus.

4. Was external cephalic version offered to this patient prior to her presentation to
   Labor and Delivery? If not, Why? What are the exclusion criteria for external
   cephalic version? Review the procedure protocol for a version.

   It is known that the incidence of PROM and preterm labor is increased in breech
   presentations. Due to this, it is important for obstetricians to diagnose the breech
   presentation as close to 37 weeks of gestation as possible, and ideally by the 36th
   week. This early diagnosis allows time for scheduling the external version and
   ultrasound examination. Otherwise, the window of opportunity to perform
   external version may be lost. Thus, careful Leopold’s maneuvers, followed by
   ultrasonography must be performed during third-trimester prenatal visits in order
   for early diagnosis.

   Exclusion criteria for external cephalic version include:
   a. Multiple pregnancy
   b. Evidence of uteroplacental insufficiency
   c. Significant third-trimester bleeding
   d. Suspected intrauterine growth restriction
   e. Amniotic fluid abnormalities
   f. Uterine malformation
   g. Placenta previa
   h. Maternal cardiac disease
   i. Pregnancy-induced hypertension
   j. Nonreassuring fetal monitoring pattern
   k. Major fetal anomaly
     Procedure protocol for external cephalic version:
     a. Ultrasound exam should be performed to confirm breech position, determine
        amniotic fluid index, note placental location, and to rule out congenital
     b. NST is performed to confirm absence of fetal heart rate abnormalities
     c. Blood is drawn for CBC and blood type and screen in the event that an urgent
        cesarean section is necessary
     d. Intravenous access should be established
     e. Tocolytic agent such as terbutaline can be administered. This is optional as its
        effectiveness in improving the success rate is equivocal. Under no
        circumstances should oral, parenteral, or general anesthesia be used because
        of the increased risk of complications.
     f. After the procedure (regardless of success or failure), a nonstress test and
        ultrasound examination should be performed to exclude fetal bradycardia and
        to confirm successful version
     g. Rhogam should be administered after the procedure to all Rh- patients
        because of a 4.1 percent risk of fetomaternal hemorrhage in these patients.

1.   American Fertility Society (1988) The American Fertility Society classifications
     of adnexal adhesions, distal tubal occlusions secondary to tubal ligation, tubal
     pregnancies, Mullerian anomalies and intrauterine adhesions. Fertil Steril., 49:
2.   Golan A, Langer R, Bukovsky I, Caspi E. (1989) Congenital anomalies of the
     Mullerian system. Fertil Steril., 51: 747-755.
3.   Jacobsen IJ, DeCherney A. (1997) Shall We operate on Mullerian defects?
     Results of conventional and hysteroscopic surgery. Human Reprod., 12: 1376-
4.   Iverson R, DeCherney A, Laufer M. (2006) Clinical manifestations and diagnosis
     of congenital anomalies of the uterus. UpToDate 2006.
5.   Cruikshank DP. (1986) Breech presentation. Clin Obstet Gynecol., 29: 255-63.
6.   Zhang J, Bowes WA Jr, Fortney JA. (1993) Efficacy of external cephalic version:
     a review. Obstet Gynecol., 82: 306-12.
7.   Sanling E, Muller-Holve W. (1975) External cephalic version under tocolysis. J
     Perinat Med., 3(2): 115-22.
8.   American College of Obstetricians and Gynecologists: ACOG practice patterns.
     External cephalic version. Int J Gynaecol Obstet., 2000 Feb; No. 413.
9.   Flamm BL, Fried MW, Lonky NM, Giles WS. (1991) External cephalic version
     after previous cesarean section. Am J Obstet Gynecol., 165(2): 370-2.