Occult fetomaternal hemorrhage in women with pathological placenta with respect to permeability

Spontaneous massive fetomaternal hemorrhage: two case reports and a literature review of placental pathology

BACKGROUND

Massive fetomaternal hemorrhage (FMH) is a rare event during pregnancy that may cause severe fetal anemia or death.

CASE PRESENTATION

This paper reports two cases of fetomaternal hemorrhage with unexplained reasons. Both cases required emergency caesarean sections for non-reassuring fetal status and were treated with neonatal blood transfusion. Fetomaternal hemorrhage was confirmed via maternal Kleihauer-Betke test.

CONCLUSION

We found parenchymal pallor, increased nucleated red blood cells (nRBCs), and syncytial knots (SKs) in the placentas, which are compatible with fetal anemia. Immunohistochemical staining indicated VEGF, CD34, and CD31 expression in the endothelial cells of the capillaries, characteristic of massive FMH placenta. This article also reviews the particular histopathological changes in FHM placenta according to the placental lesion classification system.

Placental abruption and neonatal anemia

OBJECTIVE

Placental abruption can cause maternal blood loss and maternal anemia. It is less certain whether abruption can cause fetal blood loss and neonatal anemia.

STUDY DESIGN

Retrospective multi-hospital 24-month analysis of women with placental abruption and their neonates.

RESULTS

Of 55,111 births, 678 (1.2%) had confirmed abruption; 83% of these neonates (564) had one or more hemoglobins recorded in the first day. Four-hundred-seventy (83.3%) had a normal hemoglobin (≥5th% reference interval) while 94 (16.7%) had anemia, relative risk 3.26 (95% CI, 2.66-4.01) vs. >360,000 neonates from previous reference interval reports. The relative risk of severe anemia (<1st% interval) was 4.96 (3.44-7.16). When the obstetrician identified the abruption as "small" or "marginal" the risk of anemia was insignificant.

CONCLUSIONS

Most abruptions do not cause neonatal anemia but approximately 16% do. If an abruption is not documented as small, it is important to surveille the neonate for anemia.

Effect of placenta previa on umbilical cord hematocrit value

OBJECTIVE

Placenta previa is one of the causes of neonatal anemia. This condition is mainly explained by antenatal hemorrhage and incision of the anteriorly located placenta during cesarean section. However, the mechanism of neonatal anemia in placenta previa has not been extensively studied or well elucidated. This study investigates whether placenta previa is associated with lower hematocrit levels in newborns with no antenatal hemorrhage and placental incision.

KEY FINDINGS

This prospective study investigated 47 patients with previa and 43 control patients who gave birth with a cesarean section at 34-38 weeks of gestation. Blood samples were obtained from the fetal end of the umbilical vein. The mean umbilical cord hematocrit value was 49.3% in the control patients and 46.7% in the patients with previa, and the difference was statistically significant (p = .029). No significant association was observed between hematocrit value and birth weight, gestational age, newborn gender, placenta position, or preoperative maternal hemoglobin level.

CONCLUSION

The study findings reveal that even if not complicated by antepartum or intrapartum hemorrhage, placenta previa may be associated with lower hematocrit values in newborns. Although in none of the cases, the umbilical cord hematocrit value was not as low as to be defined as anemia, this effect of previa on newborns should be considered because of the importance of iron status.

Reduced fetal movements: the case of Fetomaternal Hemorrhage. Case series and proposal of a management protocol

Fetomaternal hemorrhage (FMH) was reported more than 60 years ago for the first time defined by the transfer or transfusion of fetal blood into the maternal circulation before or during delivery. The transfused volume is usually very small but when this value exceeds, it may be clinically significant. Antenatal diagnosis of severe FMH is difficult and it can be suspected in case of reduction of fetal movements, abnormal cardiotocography and ultrasound. FMH is associated to different adverse outcomes and admission to neonatal intensive care. The low incidence of FMH limits the studies, thus being able to rely only on diagnosis and retrospective studies. We present case series of FMH and analyze the steps with the purpose of defining a flow-chart for early diagnosis and management of FMH.

The concentration of fetal red blood cells in first-trimester pregnant women undergoing uterine aspiration is below the calculated threshold for Rh sensitization

OBJECTIVES

To calculate the minimum fetal red blood cell concentration required to cause maternal Rh sensitization; validate the use of a flow cytometry protocol below that concentration; preliminarily assess the concentrations of fetal red blood cells in pregnant women before and after uterine aspiration.

STUDY DESIGN

Using pre-existing literature, we calculated the lowest concentration of fetal red blood cells found to cause sensitization within adult female circulation. We validated a two-color flow cytometry protocol using fluorescently labeled antibodies to Hemoglobin F (expressed by fetal red blood cells and adult F cells) and Carbonic Anhydrase (expressed in red blood cells during the third trimester and postnatally) by titrating second trimester cord blood into non-pregnant adult blood. We applied this flow cytometry protocol in a prospective cohort study of 42 pregnant women at 5-12 weeks gestational age undergoing uterine aspiration for induced or spontaneous abortion.

RESULTS

The calculated threshold for causing Rh sensitization was 250 fetal red blood cells per 10 million total red blood cells. We showed a linear relationship between observed and expected fetal red blood cell fractions in titrated samples. Fetal red blood cell counts were more reliable when samples acquired by flow cytometry contained at least 1 million red blood cells. All 37 subjects with evaluable paired samples demonstrated fetal red blood cell concentrations below the calculated threshold for Rh sensitization both pre- and post-procedure. The fetal RBC concentrations increased from a mean of 4.5 (median 0, range 0-57) fetal RBCS pre- to a mean of 8.6 (median 2, range 0-32) fetal RBCs post- per 10 million total RBCs (p < 0.001).

CONCLUSIONS

Flow cytometry was capable of separately quantifying fetal red blood cells and maternal F cells to very dilute concentrations. Fetal red blood cell exposure in the first trimester was well below the calculated threshold for maternal Rh sensitization in our cohort. Larger studies are warranted to confirm our pilot study findings, fill this evidence gap and inform universal guidelines for administering Rh immunoglobulin after first trimester uterine aspiration.

IMPLICATIONS

Fetal red blood cell exposure following first trimester uterine aspiration is well below the calculated threshold for maternal Rh sensitization in our cohort.

First-trimester maternal serum alpha-fetoprotein is not a good predictor for adverse pregnancy outcomes: a retrospective study of 3325 cases

Background

It is well known that second-trimester maternal serum alpha-fetoprotein (MS-AFP) is a predictor for adverse pregnancy outcomes (APOs), such as preterm birth, stillbirth, preeclampsia and small for gestational age (SGA). However, it is unknown whether first-trimester MS-AFP is also predictive of APOs.

Methods

We retrospectively reviewed the data on the first-trimester MS-AFP levels and pregnancy outcomes of 3325 singleton pregnant women. The cutoff value of 2.5 multiple of the median (MoM) was used to evaluate the risks of APOs regarding MS-AFP. The receiver operating characteristic (ROC) curves were used to evaluate the predictive efficiencies of MS-AFP to these disorders.

Results

A total of 181 pregnancies resulted in preterm birth, 32 in stillbirth, 81 in preeclampsia, and 362 in SGA. Compared to women with MS-AFP < 2.5MoM, those with MS-AFP ≥ 2.5MoM had increased risks (odds ratio, 95% confidence interval) of preterm birth (2.53, 1.65~3.88), preeclampsia (3.05, 1.71~5.43) and SGA (1.90, 1.34~2.69), and had an earlier distribution of gestational weeks at delivery (P = 0.004) and a lower distribution of neonatal birth weights (P = 0.000), but the actual between-group differences were minuscule. The areas under ROC curves were 0.572 (P = 0.001), 0.579 (P = 0.015) and 0.565 (P = 0.000) for preterm birth, preeclampsia and SGA, respectively. Subdivisions for the disorders did not obviously improve the performances of MS-AFP.

Conclusions

Elevated first-trimester MS-AFP is associated with increased risk of preterm birth, preeclampsia and SGA. However, the predictive efficiencies were low and it is not a good predictor for these APOs.

Placental mesenchymal dysplasia with a good outcome: A case report

Placental mesenchymal dysplasia (PMD), characterized by an enlarged and thickened placenta with multiple hypoechoic cystic spaces, frequently leads to a poor infantile/fetal outcome. Here, we describe a case of PMD involving an infant delivered at term with a good outcome. The fetus was male, and the proportion of the PMD lesion to the entire placenta remained constant: the PMD lesion did not enlarge. Given what is known about the pathogenesis of PMD with its association with vascular endothelial growth factor-D (VEGF-D) encoded by an X-linked gene and androgenetic/biparental mosaicism, which is consistent with female dominancy and a poor outcome, we suggest that a male sex of the fetus and non-progressing PMD may have been associated with this good outcome.

A rat model of placental inflammation explains the unexplained elevated maternal serum alpha-fetoprotein associated with adverse pregnancy outcomes

AIM

It has been reported in numerous studies that elevated maternal serum alpha-fetoprotein (MS-AFP) is associated with adverse pregnancy outcomes (APO), such as pre-eclampsia, stillbirth, preterm birth and fetal growth restriction. However, the mechanism linking elevated MS-AFP and APO is obscure. In this study, we tried to explore the mechanism by using pregnant rats.

METHODS

Lipopolysaccharide (LPS) was used to induce placental inflammation in pregnant rats. Maternal serum and placental inflammatory cytokines and placental morphology were used to assess the level of placental inflammation. The incidences of APO and the levels of MS-AFP were evaluated. The expressions of alpha-fetoprotein (AFP) in the related organs and fetal serum AFP levels were detected.

RESULTS

Compared to saline-treated pregnant rats, LPS led to elevated maternal serum and placental inflammatory cytokines and a higher rate of placental inflammation. Lipopolysaccharide resulted in the features of APO and at the same time elevated MS-AFP. Maternal serum alpha-fetoprotein levels were significantly correlated to the evaluation parameters of APO. Lipopolysaccharide did not increase the expressions of AFP in fetal liver, maternal liver and placenta, but reduced the fetal serum AFP levels.

CONCLUSION

The phenomenon that elevated MS-AFP is associated with APO, which has been reported in human pregnancies, is observed in our rat model. Placental inflammation can be the potential cause linking the two manifestations together. Although the source of elevated MS-AFP is not identified, fetal blood circulation is suspected. Our study may provide an animal model for the future studies on this subject.

Prenatal planning of placenta previa: diagnostic accuracy of a novel MRI-based prediction model for placenta accreta spectrum (PAS) and clinical outcome

PURPOSE

To investigate the diagnostic accuracy of MRI for placenta accreta spectrum (PAS) and clinical outcome prediction in women with placenta previa, using a novel MRI-based predictive model.

METHODS

Thirty-eight placental MRI exams performed on a 1.5T scanner were retrospectively reviewed by two radiologists in consensus. The presence of T2 dark bands, myometrial thinning, abnormal vascularity, uterine bulging, placental heterogeneity, placental protrusion sign, placental recess, and percretism signs was scored using a 5-point scale. Pathology and clinical intrapartum findings were the standard of reference for PAS, while intrapartum/peripartum bleeding and emergency hysterectomy defined the clinical outcome. Receiver-operating characteristic (ROC) analysis and discriminant function analysis were performed to test the predictive power of MRI findings for both PAS and clinical outcome prediction.

RESULTS

Abnormal vascularity and percretism signs were the two most predictive MRI features of PAS. The area under the curve (AUC) of the predictive function was 0.833 (cutoff 0.39, 67% sensitivity, 100% specificity, p = 0.001). Percretism signs and myometrial thinning were the two most predictive MRI features of poor outcome. AUC of the predictive function was 0.971 (cutoff - 0.55, 100% sensitivity, 77% specificity, p < 0.001).

CONCLUSION

The diagnostic accuracy of MRI, especially considering the combination of the most predictive MRI findings, is higher when the target of the prediction is the clinical outcome rather than the PAS.

Intrauterine fetal death caused by seatbelt injury

OBJECTIVE

Severe motor vehicle accidents involving pregnant women can result in fetal and neonatal death. We describe a case in which fetal death occurred due to relatively mild seatbelt injuries and present the characteristic magnetic resonance imaging (MRI) findings of the placenta.

CASE REPORT

A 26-year-old primigravid woman at 20 weeks gestation was involved in an automobile accident. Although she suffered only a seatbelt injury, fetal death subsequently occurred. Contrast-enhanced MRI showed the region compressed by the seatbelt as a low-intensity band without enhancement, and serum alpha-fetoprotein and hemoglobin F levels were elevated.

CONCLUSION

Careful monitoring, including blood and abdominal examinations, should be performed when pregnant women suffer seatbelt injuries.