Ovum Forceps: Bierer vs Sopher vs Winter Patterns

Sopher or Bierer? On most gynaecology trays both are present, both look broadly similar at a glance, and which one the surgeon reaches for is often habit rather than a decision. The jaws are not interchangeable, and the difference shows up exactly when it matters — on retained tissue that is adherent rather than loose.

What these instruments do that a curette cannot

A curette scrapes. It works along a plane, removing what is attached to the surface it is drawn across, and it is the right instrument for the endometrial layer.

Retained products of conception and retained placental fragments are not a layer. They are discrete masses sitting in the cavity, sometimes free, sometimes adherent to a patch of decidua, and a curette either misses them or shreds them into pieces that are harder to retrieve than the original mass. Ovum forceps are grasping instruments: fenestrated jaws that close around a mass, hold it, and allow it to be drawn out in one piece with gentle traction and rotation.

The fenestration is the design point. Solid jaws closing on friable tissue cut through it. A hollow, serrated jaw distributes grip across a wider area and lets the tissue bulge slightly into the opening, which is what allows a hold firm enough for traction without transecting what you are holding.

The three patterns compared

Most patterns are supplied both with and without a ratchet, and in straight and slightly curved jaw forms. That choice matters more than the width for some surgeons — see below.

Sopher

Flat jaws, fenestrated, with transverse serrations running across the grasping surface. The flat profile is the narrowest of the three in the closed position, so a Sopher passes a cervix dilated to a smaller diameter than a Bierer will. That makes it the default first-trimester instrument and the one most often paired with a standard D&C set. The narrower 9 and 12 mm jaws are the working sizes; 16 mm exists but starts to lose the access advantage that is the pattern’s reason for being.

Bierer

Heavier throughout. The jaws are deeper front-to-back and more aggressively serrated, and the wider 19 and 22 mm sizes will take hold of a volume of tissue that a Sopher would need three passes to clear. The trade is access: a closed Bierer jaw needs more cervical dilatation to pass safely, and forcing one through an under-dilated canal is a recognised route to a cervical tear. Check the dilatation against the closed jaw dimension rather than assuming.

Winter

The odd one out, and frequently misfiled. Winter placenta and ovum forceps have spoon-shaped, concave jaws with a sharpened rim rather than flat fenestrated blades. The concavity lets the jaws cup a sizeable placental fragment, and the sharp edge lets the instrument separate adherent tissue at the same time as grasping it. That combination makes it a caesarean and postpartum instrument — used through a hysterotomy or transvaginally after delivery, where access is generous and the tissue volume is large — rather than a transcervical first-trimester instrument.

Ratchet or no ratchet

A ratcheted ovum forceps holds without sustained hand pressure, which is genuinely useful when a mass needs steady traction over several seconds while it separates.

The argument against is tactile. A ratchet locks at a fixed jaw pressure, and the surgeon loses the fine feedback that tells them whether they have hold of a free-floating mass or of the uterine wall. Grasping myometrium and applying traction is the mechanism behind most perforations in this procedure, and many gynaecologists therefore prefer the unratcheted version for anything transcervical, keeping the ratchet for the more visually controlled setting of an open hysterotomy.

If your department stocks only one, stock unratcheted. It is the safer default, and a ratchet can never be un-had mid-case.

Jaw curvature and length

Slightly curved jaws follow the axis of an anteverted or retroverted uterus better than a straight instrument, reducing how much the shaft has to be angled against the cervix to reach a fundal fragment. The curve is subtle — nothing like a uterine dressing forceps — and it is oriented to work with the sounding direction established before dilatation.

Length is chosen against uterine depth. A 33 cm instrument in a small non-gravid uterus buries most of its length outside the patient and reduces control; a 26 cm instrument in a mid-trimester uterus may not reach the fundus. Sound and dilate first, as covered in our guide to Hegar dilators, then choose length against the depth you measured rather than against what is nearest on the tray.

The cervix normally needs stabilising throughout, and that is a separate instrument — see our comparison of uterine tenaculum forceps for the patterns that do that job.

Care and inspection

These instruments are box-joint ring-handled forceps, and they fail in the ways box joints fail. The fenestrated jaws trap tissue in the window and in the serrations, and anything left there through a steam cycle is baked on and effectively permanent — a jaw with residue in the serrations grips badly and is a bioburden problem besides. Brush the fenestration specifically, from both faces, during manual cleaning.

Check jaw alignment against a light before each list. Held closed, the serrations should mesh across the full width with no daylight at the tip and no lateral offset. A forceps that has been sprung — usually by being used as an extraction lever rather than a grasper — will hold at the ratchet and still let tissue slip at the tip, which is the worst of both outcomes.

The Winter’s sharpened rim needs periodic attention that the flat patterns do not. It is a cutting edge, it dulls, and a dull spoon rim tears placental tissue instead of separating it.

Sourcing

Sopher, Bierer and Winter patterns are supplied in the standard jaw widths and lengths, straight or curved, ratcheted or plain, manufactured in Sialkot to ISO 13485 and CE marked. See the surgical instruments range or contact us for a gynaecology tray built to your instrument card.