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Placental microvascular changes in twin pregnancies with abnormal umbilical artery waveforms
1Fetal Welfare Laboratory, University of Sydney, Australia.
Obstetrics and Gynecology
|April 1, 1993
Summary
Abnormal umbilical artery Doppler waveforms in twin pregnancies correlate with reduced placental microvasculature. This placental vascular disease appears to originate in the fetal circulation, not the maternal uteroplacental vessels.
Area of Science:
- Perinatology
- Fetal Medicine
- Obstetrics
Background:
- Twin pregnancies face higher risks of placental insufficiency.
- Umbilical artery Doppler (UAD) is used to assess fetal well-being.
- Placental histology provides detailed vascular structure information.
Purpose of the Study:
- To investigate the relationship between UAD waveforms and placental microvascular structure in twin pregnancies.
- To determine if abnormal UAD findings correlate with specific placental histological changes.
Main Methods:
- Histological examination of placental vasculature from 41 twin pregnancies.
- Antenatal UAD waveform analysis was performed prior to delivery.
- Comparison of placental microvessel counts between fetuses with normal and abnormal S/D ratios.
Main Results:
- Fetuses with abnormal systolic-diastolic ratios (S/Ds) exhibited reduced placental arterial vessels.
- Mean count of small arterial vessels (<90 μm) was significantly lower in placentas with high S/Ds (3.9) compared to normal S/Ds (5.6).
- P = .039 indicates a statistically significant difference.
Conclusions:
- Twin pregnancies with placental insufficiency show microvascular disease localized to the affected fetus's placenta.
- The findings suggest the placental vascular lesion originates within the fetal circulation.
- This implies a fetal-derived vascular pathology rather than a uteroplacental issue.