Association of Doppler parameters with placental signs of underperfusion in late-onset small-for-gestational-age pregnancies

Placental 11B-Hydroxysteroid Dehydrogenase Type 2 mRNA Levels in Intrauterine Growth Restriction versus Small-for-Gestational-Age Fetuses

Introduction: The objective of this study was to evaluate placental 11B-hydroxysteroid dehydrogenase type 2 (11B-HSD-2) mRNA levels in intrauterine growth-restricted fetuses (IUGR) as compared with small-for-gestational-age (SGA) fetuses according to clinical criteria. Material and Methods: Placental levels of 11B-HSD-2 mRNA levels were measured in SGA (birth weight <10th centile) and gestational-age-matched, appropriate-for-gestational-age (AGA) births. SGA was classified as IUGR (birth weight <3rd centile or <10th percentile with abnormal uterine artery Doppler or cerebroplacental ratio) or non-IUGR SGA. After RNA extraction, mRNA levels were determined by reverse transcription and quantitative PCR. Results: A total of 38 placentas were analyzed (20 AGA and 18 SGA). Among the SGA pregnancies, 13 qualified as IUGR. The activity of 11B-HSD-2 in IUGR pregnancies [0.105 (SD 0.328)] was significantly reduced compared to non-IUGR SGA [0.304 (SD 0.261); p = 0.018] and AGA [0.294 (SD 0.328); p = 0.001]. These differences remained significant after adjusting for potential confounders (such as smoking or maternal cortisol levels). Activity levels did not significantly differ between non-IUGR SGA and AGA. Discussion: IUGR fetuses had reduced 11B-HSD-2 activity in comparison with SGA and normally grown fetuses. This finding provides opportunities to develop new placental biomarkers for the phenotypic characterization of fetal smallness.

3-D volumetric MRI evaluation of the placenta in fetuses with complex congenital heart disease

INTRODUCTION

Placental insufficiency remains a common cause of perinatal mortality and neurodevelopmental morbidity. Congenital heart disease (CHD) in the fetus and its relationship to placental function is unknown. This study explores placental health and its relationship to neonatal outcomes by comparing placental volumes in healthy pregnancies and pregnancies complicated by CHD using in vivo three-dimensional MRI studies.

METHODS

In a prospective observational study, pregnant women greater than 18 weeks gestation with normal pregnancies or pregnancies complicated by CHD were recruited and underwent fetal MR imaging. The placenta was manually outlined and the volume was calculated in cm(3). Brain volume was also calculated and clinical data were also collected. Relationships, including interactive effects, between placental and fetal growth, including brain growth, were evaluated using longitudinal multiple linear regression analysis.

RESULTS

135 women underwent fetal MRI between 18 and 39 weeks gestation (mean 31.6 ± 4.4). Placental volume increased exponentially with gestational age (p = 0.041). Placental volume was positively associated with birth weight (p < 0.001) and increased more steeply with birth weight in CHD-affected fetuses (p = 0.046). Total brain and cerebral volumes were smaller in the CHD group (p < 0.001), but brainstem volume (p < 0.001) was larger. Placental volumes were not associated with brain volumes.

DISCUSSION

Impaired placental growth in CHD is associated with gestational age and birth weight at delivery. Abnormalities in placental development may contribute to the significant morbidity in this high-risk population. Assessment of placental volume by MRI allows for in vivo assessments of placental development.

An integrated model with classification criteria to predict small-for-gestational-age fetuses at risk of adverse perinatal outcome

OBJECTIVE

To develop an integrated model with the best performing criteria for predicting adverse outcome in small-for-gestational-age (SGA) pregnancies.

METHODS

A cohort of 509 pregnancies with a suspected SGA fetus, eligible for trial of labor, was recruited prospectively and data on perinatal outcome were recorded. A predictive model for emergency Cesarean delivery because of non-reassuring fetal status or neonatal acidosis was constructed using a decision tree analysis algorithm, with predictors: maternal age, body mass index, smoking, nulliparity, gestational age at delivery, onset of labor (induced vs spontaneous), estimated fetal weight (EFW), umbilical artery pulsatility index (PI), mean uterine artery (UtA) PI, fetal middle cerebral artery PI and cerebroplacental ratio (CPR).

RESULTS

An adverse outcome occurred in 134 (26.3%) cases. The best performing predictors for defining a high risk for adverse outcome in SGA fetuses was the presence of a CPR < 10th centile, a mean UtA-PI > 95th centile or an EFW < 3rd centile. The algorithm showed a sensitivity, specificity and positive and negative predictive values for adverse outcome of 82.8% (95% CI, 75.1-88.6%), 47.7% (95% CI, 42.6-52.9%), 36.2% (95% CI, 30.8-41.8%) and 88.6% (95% CI, 83.2-92.5%), respectively. Positive and negative likelihood ratios were 1.58 and 0.36.

CONCLUSIONS

Our model could be used as a diagnostic tool for discriminating SGA pregnancies at risk of adverse perinatal outcome.

Correlation between histological signs of placental underperfusion and perinatal morbidity in late-onset small-for-gestational-age fetuses

OBJECTIVE

To investigate whether signs of placental underperfusion (PUP), defined as any maternal and/or fetal vascular pathology, confer an increased risk of neonatal morbidity in late-onset small-for-gestational-age (SGA) fetuses with normal umbilical artery (UA) Doppler indices.

METHODS

A cohort of 126 SGA singleton fetuses with normal UA Doppler indices that were delivered after 34 weeks' gestation was studied. For each case, the placenta was evaluated histologically for signs of PUP using a hierarchical and standardized classification system. Neonatal morbidity was assessed according to the score calculated from the morbidity assessment index for newborns (MAIN), a validated outcome scale. The independent association between PUP and neonatal morbidity was evaluated using multivariable median regression analysis.

RESULTS

In 84 (66.7%) placentae, 97 placental histological findings that qualified as signs of PUP were observed. These PUP cases had a significantly higher incidence of emergency Cesarean section for non-reassuring fetal status (44.1% vs 21.4%, respectively; P = 0.013) and neonatal metabolic acidosis at birth (33.3% vs 14.3%, respectively; P = 0.023), than did those without PUP. The median MAIN score differed significantly between those with PUP and those without (89 vs 0, respectively; P = 0.025). This difference remained significant after adjustment for potential confounders. The proportion of cases with scores indicative of mild to severe morbidity was also significantly higher in the PUP group (31% vs 14.3%, respectively; P = 0.043).

CONCLUSION

In late-onset SGA fetuses with normal UA Doppler indices, signs of PUP imply a higher neonatal morbidity. These findings allow the phenotypic profiling of fetal growth restriction among the general population of late-onset SGA.

Placental lesions associated with acute atherosis

OBJECTIVE

Acute atherosis is a lesion of the spiral arteries characterized by fibrinoid necrosis of the vessel wall, an accumulation of fat-containing macrophages, and a mononuclear perivascular infiltrate, which can be found in patients with preeclampsia, fetal death, small-for-gestational age, spontaneous preterm labor/premature prelabor rupture of membrane, and spontaneous mid-trimester abortion. This lesion is thought to decrease blood flow to the intervillous space which may lead to other vascular lesions of the placenta. The objective of this study was to test whether there is an association between acute atherosis and placental lesions that are consistent with maternal vascular underperfusion (MVU), amniotic fluid infection (AFI), fetal vascular thrombo-occlusive disease (FVTOD) or chronic inflammation.

MATERIAL AND METHODS

A retrospective cohort study of pregnant women who delivered between July 1998 and July 2014 at Hutzel Women's Hospital/Detroit Medical Center was conducted examine 16 457 placentas. The frequency of placenta lesions (diagnosed using the criteria of the Perinatal Section of the Society for Pediatric Pathology) was compared between pregnancies with and without acute atherosis.

RESULTS

Among 16 457 women who were enrolled, 10.2% (1671/16 457) were excluded, leaving 14 786 women who contributed data for analysis. Among them, the prevalence of acute atherosis was 2.2% (326/14 786). Women with acute atherosis were more than six times as likely as those without to have placental lesions consistent with maternal underperfusion (adjusted odds ratio - aOR: 6.7; 95% CI 5.2-8.6). To a lesser degree, acute atherosis was also associated with greater risks of having either lesions consistent with FVTOD (aOR 1.7; 95% CI 1.2-2.3) or chronic chorioamnionitis (aOR 1.9; 95% CI 1.3-3), but not with other chronic inflammatory lesions, after adjusting for gestational age at delivery. In contrast, women with acute atherosis were 60% less likely to have lesions consistent with AFI, adjusting for gestational age at delivery (aOR 0.4; 95% CI 0.3-0.5).

CONCLUSIONS

Acute atherosis is associated with increased risks of having placental lesions consistent with MVU, and to a lesser extent, chronic chorioamnionitis and those consistent with FVTOD.