Keywords:
Obstetrics (Pregnancy / birth / postnatal period), Arteries / Aorta, Ultrasound-Spectral Doppler, Screening, Obstetrics
Authors:
E. G. Okwudire1, O. M. Atalabi2, O. O. Alasia1; 1Port-Harcourt/NG, 2Ibadan/NG
DOI:
10.26044/ecr2019/C-1793
Conclusion
There was a slightly higher prevalence of PrE in subjects with central placenta (9% vs 7%),
but we found no significant association between placental location and PrE X2=0.096,
p= 0.76).
This is similar to the findings by Salama et al[9] and Contro and his colleagues [7].
Seckin et al[5] however reported that PrE was significantly higher in patients with lateral placenta compared to those with central placentas( 4.5% vs.
1.6%; p = 0.027). This difference may be due to the fact that most patients (87.4%) had centrally located placenta compared to the index study which had nearly equal distribution of lateral and central placentas.
The much larger sample size of 1057 in the study by Seckin et al[5] may also have increased power to detect subtle differences which we did not demonstrate.
We analyzed the accuracy of various indices in both patients with central and lateral placentas.
Overall,
there was a greater accuracy for detection of PrE in patients with centrally located placentas compared with those with laterally located placentas (AUC of 0.76: 95% CI: 0.53 -0.99 vs 0.66: 95% CI: 0.41 -0.91). Similarly,
Antsaklis et al[11] reported low predictive accuracy for PE in patients with laterally located placenta.
This may be because the indices from the contra-lateral uterine artery in laterally located placentas which is usually greater[2,3] caused a decrease in sensitivity and overall accuracy.
North et al[12] studied the optimal method of screening for PrE using Doppler ultrasound among 458 healthy nulliparous women and reported that the placental uterine artery RI >90th centile had a sensitivity of 51% and PPV of 29% for PrE and out-performed the mean RI.
While the reported accuracy was better than that observed in the index study,
it supports the hypothesis that placental side indices should be used in screening for patients with laterally located placentas.
In conclusion,
when mean uterine artery Doppler indices were used,
accuracy of prediction of PE was less for patients with laterally located placentas compared to those that were central in location. This suggests that placental side uterine Doppler indices may be a better for screening in patients with laterally located placentas.