Images adapted from MVA, a presentation by PRH and ARHP, 2000; 2012.

MVA Manual Vacuum Aspirator Plus

  • Cap
  • Cap release
  • Valve buttons
  • Clasp
  • Plunger O-ring
  • Collar stop Retaining Clip
  • Collar stop
  • Cylinder base
  • Plunger arms
  • Plunger handle


Prepare the aspirator

  • Begin with valve buttons open and plunger pushed fully into the barrel.
  • Close valve by pushing the buttons down and forward until locked in place.


Create the vacuum

  • Pull the plunger back until its arms snap outward over the rim at the end of the barrel.
  • Make sure plunger arms are positioned over wide edges of the barrel rim.


Attach the tenaculum

  • Gently attach the tenaculum to the cervix (either anterior lip, as shown here) or posterior lip (for a retroverted uterus), closing slowly 1-2 clicks.
  • Exert gradual traction to straighten cervical canal.




Gently dilate the cervix after paracervical block

  • Use dilators of increasing size to accommodate cannula size chosen based on gestational weeks.
  • Dilator:
    • Denniston – dilate to cannula size (e.g. size 7 for 7 mm cannula)
    • Pratt – dilate to cannula size x 3 (e.g. 21 French for 7mm cannula)


Choose a cannula

  • Flexible: longer with two openings at tip
  • Rigid: larger single opening at tip
  • No significant difference safety or efficacy (Kulier 2001)
  • Larger cannula: faster aspiration, more intact tissue
  • Smaller cannula: less dilation and less resistance

Last NAF Provider’s survey (O’Connell 2009):

    • 54% used size (in mm) = weeks gestation
    • 37% used 1-2 mm < weeks gestation
    • 9% used 1-3 mm > weeks gestation
Insert the cannula

  • Apply traction to tenaculum to straighten uterus. While holding cannula with fingertips, gently insert through cervix with rotating motion.
  • Attach aspirator to cannula.
  • Do not grasp aspirator by plunger arms.


Release the valve buttons

  • When the pinch valve is released, the vacuum is transferred through the cannula into the uterus.
  • Blood, tissue, and bubbles will flow through the cannula into the aspirator.


Evacuate the uterus

  • Rotate the cannula and move it gently from fundus to the internal os, applying a back and forth motion as clinically indicated until:
    • Grittiness is felt through cannula
    • Uterus contracts and grips cannula
    • There is increased cramping, and / or
    • No more blood passes through cannula.


Choice of Vacuum for Aspiration

  • Availability / preference determine use
  • Some use > 1 MVA to facilitate emptying, or switch to EVA > 9 weeks
  • Minimal differences in pain, anxiety, bleeding, or acceptability (Dean 2003)
  • EVA sound may be audible to patients; silent, in-wall suction is available.

EVA use:

  • Turn on and check suction gauge, turn dial to adjust
  • Attach cannula
  • Open thumb valve, keep open while placing cannula in uterus
  • Once at fundus, close thumb valve to initiate suction
  • Release suction by opening thumb valve when passing out of the cervical canal.


Inspect the tissue

  • Rinse and strain the tissue
  • Place tissue in a clear container
  • Backlight is recommended to inspect tissue if gross visual inspection is non-diagnostic.


Gestational sac at 6 weeks

  • Shredded (on left) vs. intact
  • To minimize shredding, consider using MVA and/or a slightly larger cannula.


membranes and villi


Membranes and Villi (POC)

  • Frond-like villi
  • Clumps held by membrane
  • Transparent like plastic wrap
  • Luminescent; light refractory
  • Turns white if vinegar added
  • More stretchy
  • Floats more in liquid media


Decidua (not POC)

  • No fronds
  • No villi or thin membrane 
  • Opaque like wax paper
  • Less light refractory
  • Minimal color change 
  • More breakable
  • Sinks more in liquid media
  • Quantity variable

image Decidua capsularis

Caution not to confuse
a) gestational sac (8 wk) with

b) decidua capsularis,  a portion of the decidua which grows proportionally to gestational sac but is thicker and tougher (Paul 2009).

Fetal part development

Parts may be seen earlier.

≥ 10W look for 4 extremities, spine, calvarium and gestational sac.

≥12W must find all fetal parts + placenta.



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