Battledore Placenta: Definition and Clinical Significance
Battledore placenta refers to a marginal (eccentric) insertion of the umbilical cord at the edge of the placental disc, rather than the normal central or paracentral location. This anatomical variant gets its name from the resemblance to a battledore (an old-fashioned racquet used in badminton), where the cord inserts at the periphery of the placenta like a handle attached to the edge of a paddle 1.
Anatomical Characteristics
- The umbilical cord inserts at or very near the margin of the placental disc, typically within 2 cm of the placental edge 1.
- This differs from velamentous insertion, where the cord vessels separate and travel through the membranes before reaching the placenta, leaving them unprotected 1, 2.
- In battledore insertion, the cord vessels remain protected by Wharton's jelly until they reach the placental margin, making it less hazardous than velamentous insertion 1.
Clinical Implications and Outcomes
- Birth weight and placental weight are slightly and equally reduced in battledore insertion compared to normal cord insertion 3.
- The RNA/DNA ratio in placentas with battledore insertion is increased, indicating tissue stress at the cellular level 3.
- Battledore insertion has been associated with intrauterine growth restriction, though the effect is generally milder than with velamentous insertion 3.
- When coexisting with other placental abnormalities (such as circumvallate placenta), battledore insertion may contribute to adverse outcomes including preeclampsia and intrauterine fetal demise 4.
Prenatal Detection
- Gray-scale and color Doppler ultrasound can reliably identify the placental cord insertion site in 99% of cases during routine second and third trimester examinations 1.
- Systematic assessment of the placental cord insertion site should be performed at routine obstetric ultrasound to identify marginal insertions and pregnancies at risk for complications 1, 5.
- Color Doppler imaging enhances identification of the cord insertion site and helps differentiate battledore from velamentous insertion 1, 5.
Management Considerations
- Pregnancies with suspected or confirmed battledore insertion should be regarded as higher risk and require more stringent antenatal follow-up 4.
- Continuous intrapartum monitoring is recommended to detect any compromise related to cord compression at the marginal insertion site 4.
- The incidence of complications during labor may be increased with battledore insertion, warranting heightened surveillance 3.