Inherited thrombophilia and stillbirth

Temporal heterogeneity of placental segmental fetal vascular malperfusion: timing but not etiopathogenesis

Clinicopathologic correlations of segmental villous avascularity and other histological lesions of segmental fetal vascular malperfusion (SFVM) were analyzed retrospectively to determine whether lesions of various durations reflect different etiopathogeneses. The frequencies of 25 independent clinical and 43 placental phenotypes were statistically compared by ANOVA or Chi-square among 3 groups containing a total of 378 placentas with SFVM: group 1 contained 44 cases of recent SFVM (endothelial fragmentation, villous hypovascularity by CD34 immunostain, and/or stromal vascular karyorrhexis); group 2 contained 264 cases of established SFVM (clusters of avascular villi); and group 3 contained 70 cases of remote SFVM (villous mineralization). Statistically significant differences among the three study groups (p Bonferroni < 0.002) were found in four clinical variables (gestational age, frequencies of macerated stillbirth, induction of labor, and cesarean section) and in five placental variables (frequencies of fetal vascular ectasia, stem vessel luminal vascular abnormalities, diffusely increased extracellular matrix in chorionic villi, chorionic disk extravillous trophoblast microcysts, and excessive extravillous trophoblasts in the chorionic disc). In summary, the absence of statistically significant differences between the study groups regarding the most common causes of SFVM (hypertensive conditions of pregnancy, diabetes mellitus, fetal anomalies, and clinical and pathological features of umbilical cord compromise) is evidence that the three types of SFVM reflect temporal heterogeneity rather than etiopathogenesis. This evidence can be used to date the onset of fetal vascular malperfusion before delivery or stillbirth. The coexistence of different SVFM lesions of various durations indicates ongoing or repeat occurrences of FVM rather than single episodes.

Aetiology and trends of rates of stillbirth in a tertiary care hospital in the north of India over 10 years: a retrospective study

OBJECTIVE

To analyse the aetiology of stillbirth and its changing trends in a single tertiary care referral institute of northern India over a 10-year period (2007-2016).

DESIGN

Retrospective study.

SETTING

Tertiary care hospital in the north of India.

SAMPLE

Medical records of all mothers who delivered a stillborn at the institute.

METHODS

Data was collected from monthly and annual perinatal audits and causes of stillbirths were classified using Simplified CODAC classification. Annual reduction rate was calculated by linear regression analysis and Cusick test for the changing trends over 9 years.

MAIN OUTCOME MEASURES

Of 54 160 births, 3678 babies were stillborn. Over 9 years, the annual stillbirth rate has reduced significantly from 73.6 to 62.0 per 1000 total births with an average annual reduction rate of 1%. The most common causes of stillbirths were hypertensive disorders of pregnancy (27.6%), antepartum haemorrhage (19.5%), and congenital anomalies (9.3%).

CONCLUSION

The annual reduction rate (1%) of stillbirth remains low. The aetiology of stillbirths remains unchanged over a 10-year period and hypertensive disorder of pregnancy remains the single most preventable cause of stillbirth.

TWEETABLE ABSTRACT

Analysis of stillbirths over a 10-year period in an Indian institute showed a high but declining trend with annual reduction rate of 1%.

Inherited and acquired thrombophilias

Thrombophilias represent an evolving story that continues to stir controversy for care providers and obstetrical patients. The predominant thrombophilic mutations include the factor V Leiden mutation, prothrombin gene mutation G20210A, methylene tetrahydrafolate reductase C667T, and deficiencies of the natural anticoagulants proteins C and S, and antithrombin. Prospective cohort studies have provided an accurate assessment of the risk of placenta-mediated complications posed by common inherited thrombophilic conditions. Acquired thrombophilic conditions consist of the antiphospholipid antibody syndrome (APAS) and hyperhomocysteinemia. Well-conducted, placebo-controlled, randomized trials have demonstrated no benefit of anticoagulation in women with recurrent pregnancy loss and inherited thrombophilia. The routine use of anticoagulation to prevent other placenta-mediated complications in the setting of inherited thrombophilia should be considered experimental until the results of adequate clinical trials are available. Heparin anticoagulation and antiplatelet therapies are the cornerstone of treatment of APAS in pregnancy.

Management of subsequent pregnancy after an unexplained stillbirth

PURPOSE

To review the management of pregnancy after an unexplained stillbirth.

EPIDEMIOLOGY

Approximately 1 in 200 pregnancies will end in stillbirth, of which about one-third will remain unexplained. Unexplained stillbirth is the largest single contributor to perinatal mortality. Subsequent pregnancies do not appear to have an increased risk of stillbirth, but are characterized by increased rates of intervention (induction of labor, elective cesarean section) and iatrogenic adverse outcomes (low birth weight, prematurity, emergency cesarean section and post-partum hemorrhage).

CONCLUSIONS

There is no level-one evidence to guide management in this situation. Pre-pregnancy counseling is very important to detect and correct potential risk factors such as obesity, smoking and maternal disease. As timely delivery is the mainstay of management, early accurate determination of gestational age is vital. There is controversy regarding the pattern of surveillance, but evidence exists only for ultrasound and not for regular non-stress testing, nor formal fetal movement charting. There is an urgent need for more studies in this important area.

Etiology of stillbirth at term: a 10-year cohort study

OBJECTIVE

To examine etiological factors contributing to cases of intrauterine fetal demise in term pregnancies over a 10-year period.

METHODS

This was a retrospective cohort analysis of 29 908 term (37(+0) to 41(+6) weeks gestation) infants delivering in a single tertiary-referral university institution over the 10-year period from 1996 to 2005. Cases of stillbirth were identified from a computerized hospital database, and pathological, clinical, and biochemical data were reviewed for all cases. Trends were analyzed using the Cusick test for trend. Categorical data were analyzed using the Fisher's exact test, with the 5% level considered significant.

RESULTS

The incidence of intrauterine fetal demise at term was 1.8 per 1000 at-risk pregnancies. There was no significant downward trend in the rate of term stillbirth between 1996 and 2005 (p = 0.0808). Stillbirths were unexplained in 51% of cases, although in many cases a possible etiological factor was identified but not necessarily proven. There was a significant downward trend in the incidence of unexplained term stillbirths at our institution over the 10-year study period (p = 0.0105). Placental/cord factors accounted for 25% of term stillbirths and did not decrease significantly over the study period (p = 0.0953). Almost 50% of term stillbirths occurred in women who registered late or had no antenatal care. However, suboptimal antenatal care was not predictive of differences in either acceptance of perinatal postmortem or successful identification of stillbirth etiology.

CONCLUSIONS

The incidence of stillbirth at term is 2 per 1000 term pregnancies and has not changed significantly in the past 10 years. Almost 50% of term stillbirths occurred in women with suboptimal antenatal care. More than half of cases are unexplained, often resulting from an incomplete diagnostic work-up. Despite this, there has been a significant downward trend in the rates of unexplained stillbirth at term. It is imperative that a complete diagnostic work-up is performed in cases of term stillbirth, to minimize the incidence of unexplained stillbirth.

Stillbirth

In the UK, about one in 200 infants is stillborn, and rates of stillbirth have recently slightly increased. This recent rise might reflect increasing frequency of some important maternal risk factors for stillbirth, including nulliparity, advanced age, and obesity. Most stillbirths are related to placental dysfunction, which in many women is evident from the first half of pregnancy and is associated with fetal growth restriction. There is no effective screening test that has clearly shown a reduction in stillbirth rates in the general population. However, assessments of novel screening methods have generally failed to distinguish between effective identification of high-risk women and successful intervention for such women. Future research into stillbirth will probably focus on understanding the pathophysiology of impaired placentation to establish screening tests for stillbirth, and assessment of interventions to prevent stillbirth in women who screen positive.

Risk factors for antepartum and intrapartum stillbirth: a population-based study

To examine disparities in risk factors for stillbirths and its occurrence in the antepartum versus intrapartum periods. A population-based, cross-sectional study using data on women that delivered singleton births between 20 and 43 weeks in Missouri (1989-1997) was conducted (n = 626,883). Hazard ratios and 95% confidence intervals were derived from regression models and population attributable fractions were estimated to examine the impact of risk factors on stillbirth. Among African Americans, risks of antepartum and intrapartum stillbirth were 5.6 and 1.1 per 1,000 singleton births, respectively; risks among whites were 3.4 and 0.5 per 1,000 births, respectively. Maternal age > or = 35 years, lack of prenatal care, prepregnancy body mass index (BMI) > or = 30 kg/m2, and prior preterm or small-for-gestational age birth were significantly associated with increased risk for antepartum stillbirth among whites, but not African Americans. BMI < or = 18.5 kg/m2 was associated with antepartum and intrapartum stillbirth among African Americans, but not whites. The presence of any congenital anomaly, abruption, and cord complications were associated with antepartum stillbirth in both races. Premature rupture of membranes was associated with intrapartum stillbirth among whites and African Americans, but intrapartum fever was associated with intrapartum stillbirth among African Americans. These risk factors were implicated in 54.9% and 19.7% of antepartum and intrapartum stillbirths, respectively, among African American women, and in a respective 46.6% and 11.9% among white women. Considerable heterogeneity in risk factors between antepartum and intrapartum stillbirths is evident. Knowledge on timing of stillbirth specific risk factors may help clinicians in decreasing antepartum and intrapartum stillbirth risks through monitoring and timely intervention.

Etiology and prevention of stillbirth

OBJECTIVE

This is a systematic review of the literature on the causes of stillbirth and clinical opinion regarding strategies for its prevention.

STUDY DESIGN

We reviewed the causes of stillbirth by performing a Medline search limited to articles in English published in core clinical journals from January 1, 1995, to January 1, 2005. Articles before this date were included if they added historical information relevant to the topic. A total of 1445 articles obtained, 113 were the basis of this review and chosen based on the criterion that stillbirth or fetal death was central to the article.

RESULTS

Fifteen risk factors for stillbirths were identified and the prevalence of these conditions and associated risks are presented The most prevalent risk factors for stillbirth are prepregnancy obesity, socioeconomic factors, and advanced maternal age. Biologic markers associated with increased stillbirth risk are also reviewed, and strategies for its prevention identified.

CONCLUSION

Identification of risk factors for stillbirth assists the clinician in performing a risk assessment for each patient. Unexplained stillbirths and stillbirths related to growth restriction are the 2 categories of death that contribute the most to late fetal losses. Late pregnancy is associated with an increasing risk of stillbirth, and clinicians should have a low threshold to evaluate fetal growth. The value of antepartum testing is related to the underlying risk of stillbirth and, although the strategy of antepartum testing in patients with increased risk will decrease the risk of late fetal loss, it is of necessity associated with higher intervention rates.

Genetic prothrombotic risk factors in women with unexplained pregnancy loss

INTRODUCTION

Inherited thrombophilia has been associated with unexplained recurrent pregnancy loss (RPL) and stillbirth. This thrombotic tendency can manifest as thrombotic lesions in the placenta, and may lead to abortion and stillbirth. The aim of our case-control study was to investigate the prevalence of FVL and FII G20210A in women with adverse pregnancy outcome, compared to the prevalence of the same mutations in our health control group.

MATERIALS AND METHODS

102 consecutive women with unexplained pregnancy loss (55 with history of RPL, and 47 with history of stillbirth) were studied for hereditary thrombophilia. The health control group consisted of 217 healthy women from the general population.

RESULTS AND CONCLUSIONS

Of the 55 women with recurrent abortions, we found the same prevalence for the FVL and the FII G20210A(9.1%, 5 pts). (p=NS compared to control group). Of the 47 women with stillbirth, 11 (23.4%) had the FVL and 9 (19.1%) had the FII G20210A(p<0.0005 for both mutations). In our experience the prevalence of FVL and the FII G20210Amutations was significantly higher in women with unexplained stillbirth, instead the prevalence of genetic thrombophilia was high but not statistically significant in women with recurrent pregnancy loss.

The factor V Leiden and the G20210A prothrombin gene mutations are rare in women with fetal death

PROBLEM

To determine if there is an association between two commonly inherited thrombophilias, the factor V Leiden and the G20210A prothrombin mutations, and fetal death.

METHOD OF STUDY

We used a case-control study design to compare the frequencies of these mutations in women with fetal death and controls. Fetal death was the intrauterine death of the conceptus > or =10 weeks gestation. Controls had one live birth, no miscarriages, and no fetal death. Results were compared using chi square analysis.

RESULTS

One hundred and seventy-five cases and controls were identified. There were 4.6% of cases and 3.8% of controls heterozygous for the factor V Leiden mutation (NS), and 1.3% of cases and 1.7% of controls heterozygous for the prothrombin mutation (NS).

CONCLUSION

In our population, neither the factor V Leiden nor the G20210A prothrombin mutations are associated with fetal death. Further evidence is required before routine screening for these mutations can be recommended.

A life-threatening second trimester disseminated intravascular coagulopathy with protein s deficiency

Disseminated intravascular coagulopathy (DIC) is an uncommon but serious complication of pregnancy. Placental abruption is the most common associated condition among the causes of acute obstetrical DIC. We present a case of life-threatening DIC complicating placental abruption in the second trimester of pregnancy with protein S deficiency as a triggering factor, which necessitated urgent termination of pregnancy.

Poor Obstetric Outcome in Subsequent Pregnancies in Women With Prior Fetal Death

OBJECTIVE

Patients with recurrent first-trimester spontaneous abortion have been the subject of intensive investigation. However, relatively little is known about second- and third-trimester pregnancy loss. Thus, it is difficult for clinicians to optimally counsel, evaluate, and manage women with previous unexplained fetal death. Our objective was to ascertain the outcome of subsequent pregnancies in patients with prior fetal death.

METHODS

Subjects were identified from patients referred for evaluation of fetal death (occurring at >/= 10 weeks of gestation) and having at least one subsequent pregnancy. Patients with antiphospholipid antibodies were excluded. Logistic regression analysis was performed to determine the association of clinical variables with pregnancy outcome.

RESULTS

Two hundred thirty subjects met inclusion criteria. Up through the time of their first fetal death, these women had a total of 721 pregnancies, resulting in 268 (37%) live births, 230 (32%) fetal deaths, and 200 (28%) spontaneous abortions. In total, these women had 839 subsequent pregnancies, resulting in 202 (24%) live births, 209 (25%) fetal deaths, and 372 (44%) spontaneous abortions. Univariate logistic regression analysis identified older age at pregnancy (P =.009, odds ratio 0.63, 95% confidence interval 0.42-1.03) and treatment with low-dose aspirin (P =.001, odds ratio 0.41, 95% confidence interval 0.25-0.68) to be associated with a decreased risk for subsequent pregnancy loss.

CONCLUSION

Women with prior fetal death are at high risk for subsequent pregnancy loss and recurrent fetal death, with fewer than 25% of pregnancies resulting in surviving infants. These data underscore the need for additional research into the pathophysiology and prevention of recurrent fetal death.

Sex and gender issues and venous thromboembolism

At least 250,000 episodes of VTE leading to hospitalization or death are estimated to occur in the United States each year. A number of clinical and demographic risk factors for VTE are recognized,with the latter including both age and race. Overall,the incidence of VTE does not appear to vary significantly by sex, as evidenced by a lack of consistency in the magnitude and even direction of effect of sex in a variety of epidemiologic studies of varying design. Several studies have shown a higher incidence among women than men during childbearing age. The issue of a gender effect on the natural history of VTE has not been well studied. The main influence of gender on VTE is the relationship between female gender and several well-recognized clinical risk factors for VTE:oral contraceptive use, hormone replacement therapy, estrogen receptor modulator therapy, and pregnancy. Hormonal therapies are associated with a twofold to threefold increase in VTE incidence. Risk is higher with some formulations than others, during initial use, and among women who are obese, smoke, or have one of several forms of heritable thrombophilia. The pregnant state is associated with a threefold to fivefold increase in VTE risk, and thromboembolism is a major cause of peripartum death. Heritable thrombophilias are also important co-determinants of VTE risk in pregnancy. The mechanisms through which pregnancy and hormonal therapies increase VTE risk have not been definitively established, but hormonal effects on levels of coagulation and anticoagulation factors likely play a role. Venous compression and venous injury also contribute to increased risk during pregnancy and the puerperium. Approaches to diagnosis of VTE in the pregnant woman are largely the same as in the nonpregnant patient, but special treatment considerations do apply. Warfarin is embryopathic, particularly between the 6th and 12th weeks of pregnancy, and should be avoided in favor or heparin or low-molecular weight heparin when treatment of the pregnant woman is necessary. Guidelines have been published to assist the clinician in decision making about prophylaxis of pregnant women at increased risk or pregnancy-related or post-partum VTE.

Factor XII deficiency is strongly associated with primary recurrent abortions

OBJECTIVE

To evaluate factor XII deficiency in women with primary and secondary recurrent abortion.

DESIGN

Prospective case-control study.

SETTING

University hospital.

PATIENT(S)

Sixty-seven women with primary and 33 women with secondary recurrent abortion of unexplained nature and 49 healthy controls with no history of thrombotic disease or adverse pregnancy outcomes. MAIL OUTCOME MEASURE(S): Plasma factor XII activity, activated protein C resistance, factor V Leiden mutation analysis, protein C, protein S, antithrombin III, karyotyping, and anticardiolipin antibodies.

RESULT(S)

Ten of 67 women with primary recurrent abortion (14.9%) and 4 of 33 women (12.1%) with secondary recurrent abortion had reduced factor XII activity (<60%). These results are highly significant in the former group and showed a tendency toward significance in the latter group. All controls had normal factor XII activity.

CONCLUSION(S)

Factor XII deficiency is strongly associated with primary recurrent abortion, and women with secondary recurrent abortion show a tendency toward factor XII deficiency.

Testing for hematologic disorders and complications

This review summarizes state-of-the-art and emerging techniques in the antenatal diagnosis of fetal anemia and hemoglobinopathies. Fetal anemia may result from hemolytic disease, hemorrhage, suppression of erythropoiesis, infection (eg, parvovirus B19), or trauma. The clinical laboratory plays an essential role in the evaluation of these disorders by way of the use of various hematologic, biochemical, serologic, cytometric, and molecular genetics methods. Hemoglobinopathies are the most common class of single gene disorders worldwide. The authors have used the example of homozygous alpha-thalassemia major (Hb Barts disease) as a paradigmatic case for antenatal hemoglobinopathy screening. Perhaps the most familiar indication for hematologic screening in pregnancy is HDFN, most commonly in pregnancies previously sensitized to the RhD antigen. All pregnant women, regardless of their past medical or obstetric history or previous antibody screens, should have ABO/Rh blood typing and a red cell antibody screen performed at the first prenatal visit. Long-established methods for assaying FMH (KB method), microcytosis (hemogram with red cell indices), and blood group incompatibility (direct antigen test, serologies) remain critical for rapid, sensitive diagnosis. Analysis of fetal free DNA in maternal plasma holds the promise for rapid, ultrasensitive, and noninvasive detection of many fetal hematologic disorders.