MALPRESENTATIONS INCLUDING BREECH


I. Terms used to describe location and position of fetus:

  1. "Lie" = relationship of long axis of fetus to long axis of mother (longitudinal, tansverse, oblique)
  2. "Presentation" = What portion of the fetus is foremost in the birth canal
  3. "Position" = Orientation of some reference point on the fetus to one on the mother, usually the occipit of the fetus
    1. Hints for determining position
      1. The anterior fontanel i s larger & forms a CROSS
      2. The posterior fontanel is smaller & forms a "Y"
      3. Try to feel for an ear & see which way it bends
  4. Note--"Asynclitism" = lateral flexion of fetal head; normally occurs in small degrees; in large amounts can interfere with normal birth

 

II. Occiput Posterior position

  1. Diagnostic clues
    1. Prolonged labor
    2. Back pain
    3. Asymmetric cervical dilation
    4. Anterior fontanel being palpable and posterior fontanel not being palpable
  2. Can produce problems with delivery because fetal neck extension (resulting from occiput in the sacral hollow) results in a larger diameter (chin-apex) being presented to the pelvic inlet, as opposed to the occipito-frontal diameter, which is typically what's presented in OA position
  3. If attempting vacuum extraction, put over the posterior fontanel for better vectors (i.e. placement of vacuum extractor is more towards maternal posterior than in OA presentation)

III. Breech presentation

  1. Different types
    1. "Frank" = hips flexed, knees extended
    2. "Complete" = hips & knees flexed
    3. "Footling" = at least one hip & knee extended, resulting in foot as the presenting part
  2. Treatment--To convert to cephalic presentation
    1. If discovered before labor, there are exercises that have been recc'd (though no data) to resolve it
    2. External cephalic version-Successful in some cases but may carry risk of umbilical cord entanglement or abruptio placentae
    3. Moxibustion
      1. 260 primigravids at 33wks with breech presentation confirmed on u/s and no other pregnancy complications randomized to moxibustion of accupoint BL67 (lateral 5th toe) with Artemisia vulgaris 2x/d x 7d (with additional 7d if still breech after first 7d) vs. routine care but no intervention for breech. All w/persistent breech at 35wks were offered ext. cephalic version. 75.4% of moxibustion group were vertex at birth vs. 47.7% of control group (p < 0.01). 24pts in control group and 1 in moxibustion group had version. At birth, 75.4% in intervention group and 62.3% in control group were cephalic (p = 0.02) (JAMA 280:1580, 1998)
      2. In a study in 212 women 34-36wks gestation with singleton fetus in breech position randomized to moxibustion (at point BL67) x 20min, up to 14 sessions over 2 wks, vs. expectant management, there was no sig. diff. in final presentation at delivery, mode of delivery, or various other maternal or fetal outcomes (Obs. Gyn. 114:1034, 2009-AFP) 
  3. Vaginal breech delivery
    1. 2,083 women w/singleton fetuses in frank or complete breech position (footling not allowed to be randomized) at 37wks randomized to c/s at 38wks (assuming no spontaneous conversion to cephalic presentation) vs. vaginal delivery. Vaginal group had RR 3.1 for neonatal mortality or serious morbidity (5% vs. 1.6%, sig.); no diff. in materanl outcomes (Lancet 356:1375, 2000--FP News; JW)

(Sources include 2002 Advanced Life Support in Obstetrics course syllabus by American Academy of Family Physicians)