Placental laterality and uterine blood flow at 20–40 weeks’ gestation in low-risk pregnancies

Placental location and obstetrical-neonatal outcomes: A retrospective study

OBJECTIVE

To explore the potential association of lateral placentation with pregnancy outcome.

METHODS

The database of a tertiary medical center was searched for women who gave birth to a singleton neonate from 2012 to 2020 for whom placental location was documented during antepartum sonographic examination. Clinical data were compared between patients with a central (anterior/posterior/fundal) or lateral placenta using standard statistics. The primary outcome measure was neonatal birthweight, and secondary outcome measures were pregnancy complications and mode of delivery.

RESULTS

The cohort included 12 306 women: 11 608 (94%) with a central placenta and 698 (5.6%) with a lateral placenta. The lateral placenta group had higher rates (P < 0.05) of prior and current cesarean delivery, assisted delivery, and preterm birth. On multivariate regression analyses, placental location (adjusted odds ratio [aOR], 1.36; 95% confidence interval [CI], 1.11-1.66) and maternal age (aOR, 1.02; 95% CI, 1.01-1.03) were associated with risk of preterm birth. Lateral placenta (aOR, 1.22; 95% CI, 1.02-1.47), maternal age (aOR, 1.07; 95% CI, 1.06-1.08), parity (aOR, 0.32; 95% CI, 0.28-0.35), and prior cesarean delivery (aOR, 12.00; 95% CI, 10.60-13.60) were associated with risk of current cesarean delivery.

CONCLUSION

The findings suggest that lateral placentation may pose a risk of preterm birth and cesarean delivery compared with central placentation.

Lateral placentation and adverse perinatal outcomes

Lateral placentation may compromise placental perfusion, and we aimed to assess whether it impacts pregnancy outcomes. This single-center retrospective study included 1203 singleton pregnancies, categorized into two groups according to placental location. Women with lateral placenta had significantly higher risk of preterm birth <37 weeks (aOR 2.99) and <34 weeks (aOR 3.92), and gestational diabetes (aOR 2.72), compared to women with central placenta. Mean birth weight and small for gestational age (SGA) rates were similar between groups. Our findings suggest that lateral placenta may be associated with increased risk for preterm birth but not for SGA.

The effect of placental laterality at 20-24 gestational weeks on uterine artery doppler indices, fetal growth and preeclampsia

BACKGROUND

This study aimed (i) to assess the potential effect of placental location on uterine artery (UtA) pulsatility index (PI) and offspring birthweight (BW), and (ii) to examine the potential association of unilaterally increased UtA PI with preeclampsia (PE) or low BW.

MATERIALS AND METHODS

This was an asynchronous cohort study of singleton pregnancies between 20⁺⁰ and 23⁺⁶ gestational weeks resulting in live birth, for whom the placental site (posterior, anterior, fundal, previa, right lateral, or left lateral) and bilateral UtA PI measurements were recorded. The effect of placental location on mean BW and UtA mean PI z-scores was assessed using t-test or ANOVA and post-hoc tests, as appropriate. The UtA PI measurements were then grouped into three categories (normal mean PI; unilaterally increased PI with normal mean; increased mean PI) and we calculated the odds ratios (ORs) of unilaterally increased or increased mean PI vs. normal mean PI for PE, BW <10th centile and BW <5th centile. The independent association of placental location, UtA PI category (normal mean, unilateral increase with normal mean, increased mean PI) and UtA PI z-score with PE, BW <10th centile and BW <5th centile was then assessed using logistic regression.

RESULTS

The analysis included 5506 pregnancies. A lateral placenta was associated with higher mean PI z-score (p = .0001) and lower BW (p = .003) than non-lateral placenta. Compared with normal mean UtA PI, a unilaterally increased PI with a normal mean was associated with increased risk for PE (OR 4.3, 95%CI 1.9-9.7), BW <10th centile (OR 1.7, 95%CI 1.3-2.4) and BW <5th centile (OR 1.8, 95%CI 1.1-2.9). Similarly, increased mean UtA PI was also associated with increased risk for PE, BW <10th and BW <5th centile (OR 9.1, 95%CI 4.8-17.3; OR 4.4, 95%CI 3.5-5.7; OR 7.0, 95%CI 5.1-9.6, respectively). When assessing the independent association of placental location and UtA PI with PE and low BW, only mean UtA PI remains a significant predictor.

CONCLUSIONS

A lateral placenta is associated with a higher mean UtA PI and lower BW. Unilaterally increased UtA PI still carries a greater risk of PE and low BW than bilaterally normal PI, however this effect appears to be eventually mediated through mean UtA PI z-score, which is relatively increased in these cases.

First trimester Doppler velocimetry of the uterine artery ipsilateral to the placenta improves ability to predict early-onset preeclampsia

This study sought to investigate the effects of placental laterality on the measurements of uterine artery (UtA) Doppler velocimetry and their application in predicting early-onset preeclampsia (PE).We conducted a prospective cohort study on all women with singleton, uncomplicated pregnancies scheduled for first-trimester nuchal translucency at our institution. Pulsatility index (PI) for both UtAs was measured by Doppler velocimetry, and placental laterality was determined. Additionally, pregnancy outcome data were abstracted from the medical records. Receiver operating characteristic curves (ROCs) were plotted.Of the 304 patients enrolled, 247 met the inclusion criteria. Among these patients, 240 had uncomplicated delivery, while 7 had early delivery at <34 weeks due to PE. For the uncomplicated pregnancies, PI measurements of the UtA ipsilateral to the placenta were similar (left versus right UtA: 1.06 ± 0.38 vs. 1.04 ± 0.40; P = .745). However, PI measurements of the UtA contralateral to the placenta differed significantly (left versus right UtA: 1.45 ± 0.51 vs. 1.3 ± 0.47; P = .027). In predicting early-onset PE, the ideal cut-off value for the placental side PI was 1.91, with sensitivity 100% and specificity 96.3%. For nonplacental side PI, the ideal cut-off value for PI was 1.975, with sensitivity 57.1% and specificity 79.2%. Using the mean of the left and right UtA PI, the ideal cut-off value was 1.63, with sensitivity 100% and specificity 74.2%.ROC analysis confirmed that PI measurements of the UtA on the placental side were significantly lower than those on the contralateral side, PI measurements of the UtA ipsilateral to the placenta were similar.

Digital auscultation of the uterine artery: a measure of uteroplacental perfusion

This observational study investigated digital auscultation for the purpose of assessing the clinical feasibility of monitoring vascular sounds in pregnancy. The study was performed at the Regional Hospital Viborg, Denmark, and included 29 pregnant women, 10 non-pregnant women and 10 male participants. Digital auscultation was performed with an electronic stethoscope bilaterally near the uterine arteries and correlated to the clinical diagnosis of preeclampsia (PE), intrauterine growth restriction (IUGR) or normal pregnancy in the group of pregnant participants. In the group of non-pregnant participants, digital auscultation was performed as control measurements in the same anatomical positions. The auscultations displayed pulse waveforms comprising systolic and diastolic periods in 20 of the 29 pregnant participants. However, in the non-pregnant and male participants, the pulse waveforms were absent. The pulsatile patterns are thus likely to originate from the arteries in relation to the pregnant uterus. In the participants displaying pulse waveforms, the presence of a dicrotic notch appeared with a sensitivity of 89% and a specificity of 100% in the discrimination of normal pregnancies (n  =  11) from pregnancies with PE or IUGR (n  =  9), (p  <  0.001). This preliminary study shows the potential of identifying vascular complications during pregnancy such as preeclampsia and intrauterine growth restriction. The morphology of the derived pulse contour should be investigated and could be further developed to identify pathophysiology.