Genetic background and risk of postpartum haemorrhage: results from an Italian cohort of 3219 women

Human Genetic Variation in F3 and Its Impact on Tissue Factor-Dependent Disease

Tissue factor (TF) is the primary initiator of blood coagulation in humans. As improper intravascular TF expression and procoagulant activity underlie numerous thrombotic disorders, there has been longstanding interest in the contribution of heritable genetic variation in F3, the gene encoding TF, to human disease. This review seeks to comprehensively and critically synthesize small case-control studies focused on candidate single nucleotide polymorphisms (SNPs), as well as modern genome-wide association studies (GWAS) seeking to discover novel associations between variants and clinical phenotypes. Where possible, correlative laboratory studies, expression quantitative trait loci, and protein quantitative trait loci are evaluated to glean potential mechanistic insights. Most disease associations implicated in historical case-control studies have proven difficult to replicate in large GWAS. Nevertheless, SNPs linked to F3, such as rs2022030, are associated with increased F3 mRNA expression, monocyte TF expression after endotoxin exposure, and circulating levels of the prothrombotic biomarker D-dimer, consistent with the central role of TF in the initiation of blood coagulation.

Women with severe postpartum hemorrhage have a decreased endogenous thrombin potential before delivery

BACKGROUND

Severe postpartum hemorrhage (PPH), defined as a blood loss ≥1000 mL, is associated with maternal morbidity and mortality.

OBJECTIVES

We aimed at characterizing coagulation properties of predelivery plasmas from pregnant women with thrombin generation assay and hemostatic biomarkers (plasminogen activator inhibitor-1, tissue factor [TF], and thrombomodulin).

METHODS

A nested case-control study was conducted within the "Study of Biological Determinants of Bleeding Postpartum," a French prospective cohort study, in order to compare women with severe PPH (cases) and controls matched for age, body mass index, term, and mode of delivery. Plasma was collected at entry in the delivery room, and blood loss was measured objectively. The predelivery endogenous thrombin generation potential (ETP) was measured in plasma using calibrated automated thrombinography and low TF concentration. Hemostatic biomarkers were measured using ELISA kits.

RESULTS

A total of 142 women (71 cases and 71 controls) were investigated. There was no difference in the median lag phase, thrombin peak, and time to peak between cases and controls. However, median predelivery ETP was lower in cases than in controls (2170 vs 2408 nM.min, P < .0001), independently of mode of delivery and PPH etiology. Median plasminogen activator inhibitor-1 and TF levels were higher in cases compared with controls (107.4 vs 68.1 ng/mL, P = .0003; 34.4 vs 27.4 pg/mL, P = .007), whereas thrombomodulin levels did not differ between the 2 groups.

CONCLUSION

Among thrombin generation assay parameters, predelivery ETP levels may have a predictive value for severe PPH.

Family history of postpartum hemorrhage is a risk factor for postpartum hemorrhage after vaginal delivery: results from the French prospective multicenter Haemorrhages and Thromboembolic Venous Disease of the Postpartum cohort study

BACKGROUND

Postpartum hemorrhage is a major component of perinatal morbidity and mortality that affects young women worldwide and is still often unpredictable. Reducing the incidence of postpartum hemorrhage is a major health issue and identifying women at risk for postpartum hemorrhage is a key element in preventing this complication.

OBJECTIVE

This study aimed to estimate postpartum hemorrhage prevalence after vaginal delivery and to identify postpartum hemorrhage risk factors.

STUDY DESIGN

Unselected pregnant women ≥16 years of age admitted to 1 of 6 maternity wards in Brittany (France) for vaginal birth after 15 weeks of gestation were recruited in this prospective, multicenter cohort study between June 1, 2015, and January 31, 2019. Postpartum hemorrhage was defined as blood loss ≥500 mL in the 24 hours following delivery. Independent risk factors for postpartum hemorrhage were determined using logistic regression. Missing data were imputed using the Multivariate Imputation by Chained Equations method.

RESULTS

Among 16,382 included women, the postpartum hemorrhage prevalence was 5.37%. A first-degree family history of postpartum hemorrhage (adjusted odds ratio, 1.63; 95% confidence interval, 1.24-2.14) and a personal transfusion history (adjusted odds ratio, 1.90; 95% confidence interval, 1.23-2.92) were significantly associated with postpartum hemorrhage. The use of oxytocin during labor was also a risk factor for postpartum hemorrhage (adjusted odds ratio, 1.24; 95% confidence interval, 1.06-1.44). Inversely, smoking during pregnancy and intrauterine growth restriction were associated with a reduced risk for postpartum hemorrhage (adjusted odds ratio, 0.76; 95% confidence interval, 0.63-0.91, and 0.34; 95% confidence interval, 0.13-0.87, respectively).

CONCLUSION

In addition to classical risk factors, this study identified a family history of postpartum hemorrhage and personal transfusion history as new characteristics associated with postpartum hemorrhage after vaginal delivery. The association of postpartum hemorrhage with a family history of postpartum hemorrhage suggests a hereditary hemorrhagic phenotype and calls for genetic studies. Identifying women at risk for postpartum hemorrhage is a key element of being prepared for this complication.

Pregnancy-Associated Bleeding and Genetics: Five Sequence Variants in the Myometrium and Progesterone Signaling Pathway are associated with postpartum hemorrhage

Bleeding in early pregnancy and postpartum hemorrhage (PPH) bear substantial risks, with the former closely associated with pregnancy loss and the latter being the foremost cause of maternal death, underscoring the severity of these complications in maternal-fetal health. Here, we investigated the genetic variation underlying aspects of pregnancy-associated bleeding and identified five loci associated with PPH through a meta-analysis of 21,512 cases and 259,500 controls. Functional annotation analysis indicated candidate genes, HAND2, TBX3, and RAP2C/FRMD7, at three loci and showed that at each locus, associated variants were located within binding sites for progesterone receptors (PGR). Furthermore, there were strong genetic correlations with birth weight, gestational duration, and uterine fibroids. Early bleeding during pregnancy (28,898 cases and 302,894 controls) yielded no genome-wide association signals, but showed strong genetic correlation with a variety of human traits, indicative of polygenic and pleiotropic effects. Our results suggest that postpartum bleeding is related to myometrium dysregulation, whereas early bleeding is a complex trait related to underlying health and possibly socioeconomic status.

Risk Factors for Postpartum Hemorrhage in a Thai-Myanmar Border Community Hospital: A Nested Case-Control Study

Postpartum hemorrhage (PPH) is a common complication of pregnancy and a global public health concern. Even though PPH risk factors were extensively studied and reported in literature, almost all studies were conducted in non-Asian countries or tertiary care centers. Our study aimed to explore relevant risk factors for PPH among pregnant women who underwent transvaginal delivery at a Thai–Myanmar border community hospital in Northern Thailand. An exploratory nested case-control study was conducted to explore risk factors for PPH. Women who delivered transvaginal births at Maesai hospital from 2014 to 2018 were included. Two PPH definitions were used, which were ≥ 500 mL and 1000 mL of estimated blood loss within 24 h after delivery. Multivariable conditional logistic regression was used to identify significant risk factors for PPH and severe PPH. Of 4774 women with vaginal births, there were 265 (5.55%) PPH cases. Eight factors were identified as independent predictors for PPH and severe PPH: elderly pregnancy, minority groups, nulliparous, previous PPH history, BMI ≥ 35 kg/m², requiring manual removal of placenta, labor augmentation, and fetal weight > 4000 gm. Apart from clinical factors, particular attention should be given to pregnant women who were minority groups as PPH risk significantly increased in this population.

Identification of mutations in SLC4A1, GP1BA and HFE in a family with venous thrombosis of unknown cause by next-generation sequencing

Various risk factors, including high age, female gender, obesity and certain genetic defects have been linked to venous thrombosis. A Taiwanese family with venous thrombosis of unknown cause were enrolled in the present study. In this pedigree, two women without any specific underlying diseases suffered from venous thrombotic events at the same age. No specific risk factors or coagulation abnormalities were identified. The main proband's younger brother also had intestinal arterial thrombosis at 54 years of age. Therefore, it was hypothesized that familial genetic defects may be the cause of venous thrombosis within this family. Blood samples collected from certain members of this pedigree were subjected to whole-exome sequencing, and three genetic variants were identified, including a missense variant of solute carrier family 4 member 1 (SLC4A1) (c.388G>A), a deletion on glycoprotein Ib platelet α subunit (GP1BA) (c.1322_1344del23) and an insertion in the splice site of homeostatic iron regulator (HFE). To date, none of these three genetic variants have been reported to be associated with venous thrombosis, to the best of our knowledge. The present study suggests that these genetic variants of SLC4A1, GP1BA and HFE may be associated with venous thrombosis in an Asian pedigree.

Management of pregnancy and emergency caesarean delivery in a patient with type IIB von Willebrand disease and severe preeclampsia: A case report and literature review

Main purposes of the study

To report an example of how concurrent von Willebrand disease type IIB disease and severe preeclampsia can be safely managed to and to review the current literature to evaluate management approaches that have proven safe and effective.

The basic procedures used

Report of case with a review of literature.

Conclusions

Through regular von Willebrand factor and platelet replacement during the prenatal period, immediately pre-delivery, and as needed intraoperatively and postoperatively, women with von Willebrand disease type IIB can safely undergo both normal spontaneous vaginal deliveries and caesarean deliveries, even with concurrent disorders like preeclampsia. Further studies with larger sample size are required to solidify management concepts in this disease concurrent with pregnancy.

An update on the management of bleeding disorders during pregnancy

PURPOSE OF REVIEW

The morbidity and mortality of postpartum hemorrhage (PPH) in women with an underlying bleeding disorder requires vigilance by the hematologist.

RECENT FINDINGS

Recent studies suggest that women with underlying bleeding disorders may be 'undertreated' at the time of delivery in aiming for too low a target elevation that historically per numerous society guidelines has aimed for VWF/FVIII:C levels to be 'only' greater than 50% when in actuality the levels should be akin to what is achieved in a normal pregnancy. The result appears to be an increase in the rate and degree of PPH. In this context, although recent studies imply DDAVP is well tolerated, DDAVP may not be appropriate because it may not raise the levels into the normal supraphysiological range nor maintain it for several days. Particularly in women with rare bleeding disorders, i.e., non-

FVIII

C or VWF deficient, adjunctive antifibrinolytic therapy, e.g., tranexamic acid, appears to be in order as a prophylactic measure.

SUMMARY

Women with an underlying bleeding disorder appear to be at a heightened risk for PPH if the respective coagulation factor level is not appropriately replaced to the level that is physiologically achieved in a normal pregnancy. Furthermore, there appears to be underuse of tranexamic acid for prophylaxis of PPH in this population.