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The cause of meconium passage in utero is controversial, traditionally being considered evidence of fetal stress and hypoxia, and also associated with intra-amniotic inflammation/infection. It is now recognized to also occur in the absence of fetal stress. Autopsy studies have shown that many term stillborns (SB) have hypoxic/ischemic brain injury and other evidence of stress preceding the time period immediately before demise, including acute thymic involution (ATI); however, these findings, along with placental findings, have not been previously correlated with meconium-stained amniotic fluid (MSAF). 35 structurally normal singleton term SB (21 early term, 14 full/late term) with complete autopsies, including brain and placental examination, were identified. MSAF was visually identified at delivery and confirmed on the placental examination. Autopsy evaluation included brain injury and ATI. Placental evaluation included maternal and fetal vascular malperfusion and acute and chronic inflammatory lesions. Demographic and clinical features were compared. 18 (51%) SB had MSAF, and 17 (49%) had clear amniotic fluid (CAF). The was no significant difference in brain injury in the MSAF vs CAF group, including older gray matter injury (karyorrhexis) (67% vs 47%), recent gray matter injury (red neurons, but no karyorrhexis) (28% vs 35%), white matter injury (50% vs 29%), and hemorrhage (22% vs 24%). Severe ATI was more frequent in the MSAF vs CAF group (61% vs 24%, p =.04). There was no significant difference in placental lesions between groups, including acute maternal inflammation (39% vs 18%), acute fetal inflammation (6% vs 6%), fetal vascular malperfusion (11% vs 18%), maternal vascular malperfusion (39% vs 35%), and chronic inflammatory lesions (39% vs 29%). The MSAF group was more likely to be full/late term than early term (72% vs 28%), in contrast to the CAF group (6% vs 94%) (p =.0001). There was no difference in other clinical factors evaluated. 51% of term SB had MSAF, and, in contrast to the CAF group, these were significantly more likely to be full/late term. Brain injury was frequent in both MSAF and CAF groups, supporting hypoxia as the mechanism of demise in most of these SB. No placental lesions correlated with MSAF, including inflammation. This suggests that hypoxia is the cause of the MSAF in these SB, but that some additional biologic factor present in the full/late term SB, but not present in the early term SB, including possibly gastrointestinal maturation, is necessary for the meconium passage. [ABSTRACT FROM AUTHOR]

It is a generally held concept that finding increased aspirated amniotic fluid squames at autopsy supports a diagnosis of acute fetal asphyxia, the massive aspiration of squames being an indicator of terminal gasping. To evaluate this concept, we identified autopsies on 15 third-trimester stillborns with clinical acute placental abruption (acute asphyxia); 13 also had thymic petechiae and none had severe acute thymic involution, findings also supporting acute asphyxia. Thirty third-trimester stillborns with findings supporting a subacute or chronic mode of death, including severe thymic involution and absence of thymic petechiae, comprised the comparison group. Intra-alveolar squames were scored as 0, no squames; 1+, scattered squames singly or in small groups; and 2+, squames in many alveoli, at least focally in compacted clusters. In all cases, the squames were patchily distributed, and none received a score of 0. In the abruption group, the intra-alveolar squames were scored as 1+ in 12 (80%) and as 2+ in 3 (20%) cases, while in the comparison group, the squames were scored as 1+ in 20 (67%) and 2+ in 10 (33%) cases (P = NS). There was also no difference in the quantification of intra-alveolar squames in term compared to preterm stillborns. In conclusion, quantification of intra-alveolar squames did not aid in separating an acute mode of death (acute asphyxia) from subacute or chronic modes of death. [ABSTRACT FROM AUTHOR]

Objective: To determine frequency, stage and grade of placental histologic acute maternal inflammatory response (MIR) and fetal inflammatory response (FIR) in meconium-stained amniotic fluid (MSAF) in our predominantly African-American population.Methods: Term placentas with MSAF (n = 310) were evaluated for MIR/FIR, including stage/grade, and compared with placentas with clear amniotic fluid (AF) (n = 250). MIR/FIR were also evaluated in thick compared to thin MSAF subgroups. Selected demographic and clinical features were compared.Results: MIR and FIR were present in 57.7 and 40.3% of the MSAF compared to 44.0 and 29.2% of the clear AF group, respectively (p = .001 and .008). MIR with FIR was present in 35.8% of the MSAF compared to 25.2% of the clear AF group (p = .008); however, there was no significant difference in frequency of MIR without FIR between groups. There was no significant difference in frequency of MIR/FIR in thick compared to thin MSAF; however, thick MSAF was associated with higher FIR stage compared to thin MSAF (29.2 versus 5.4%, p = .004). This association was not seen with MIR stage or MIR/FIR grade.Conclusions: Histologic MIR and FIR are frequent findings in MSAF. Thick MSAF is associated with higher FIR stage when compared to thin MSAF. [ABSTRACT FROM AUTHOR]

Objective: To determine the frequency and type of histopathologic lesions in placentas delivered by women with a normal pregnancy outcome. Methods: This retrospective cohort study included placental samples from 944 women with a singleton gestation who delivered at term without obstetrical complications. Placental lesions were classified into the following four categories as defined by the Society for Pediatric Pathology and by our unit: (1) acute placental inflammation, (2) chronic placental inflammation, (3) maternal vascular malperfusion and (4) fetal vascular malperfusion. Results: (1) Seventy-eight percent of the placentas had lesions consistent with inflammatory or vascular lesions; (2) acute inflammatory lesions were the most prevalent, observed in 42.3% of the placentas, but only 1.0% of the lesions were severe; (3) acute inflammatory lesions were more common in the placentas of women with labor than in those without labor; (4) chronic inflammatory lesions of the placenta were present in 29.9%; and (5) maternal and fetal vascular lesions of malperfusion were detected in 35.7% and 19.7%, respectively. Two or more lesions with maternal or fetal vascular features consistent with malperfusion (high-burden lesions) were present in 7.4% and 0.7%, respectively. Conclusion: Most placentas had lesions consistent with inflammatory or vascular lesions, but severe and/or high-burden lesions were infrequent. Mild placental lesions may be interpreted either as acute changes associated with parturition or as representative of a subclinical pathological process (intra-amniotic infection or sterile intra-amniotic inflammation) that did not affect the clinical course of pregnancy. [ABSTRACT FROM AUTHOR]

Objective: Examine the association between placental inflammation and neonatal infections, and 25OH vitamin D (25OH D) levels at birth among very low birth weight infants (VLBWI).Study Design: Serum 25OH D levels were measured in 89 VLBWI (≤1250 g) and 47 mothers on day one, and in 78 infants on day 21. Placentas were examined for maternal and fetal inflammation. Infants were divided into deficient (≤10 ng/ml) and adequate (>10 ng/ml) groups based on 25OH D levels on day 1.Results: Mean ± SD maternal levels of 25OH D (21 ± 9 ng/ml) correlated with infants' levels (15 ± 8 ng/ml), (p < .001). 25OH D levels were lower in deficient (32/89) than in adequate group (8 ± 2 versus 20 ± 7 ng/ml, p = .011). Infants' 25OH D levels rose significantly by day 21 (p < .001). Univariate analyses showed no differences between infant groups in maternal or fetal inflammation, or neonatal infections (p > .05). Logistic regression analyses revealed no association between deficient 25OH D levels and the odds of maternal or fetal inflammation or other infections. Levels of 25OH D did not correlate with severity of placental inflammation.Conclusions: Deficient levels of 25OH D at birth are not associated with the occurrence of placental inflammation or neonatal infections among VLBWI. [ABSTRACT FROM AUTHOR]