Association between newborn birth weight and the risk of postpartum maternal venous thromboembolism: a population-based case-control study

Evaluating Thromboprophylaxis Strategies for High-Risk Pregnancy: A Current Perspective

Venous thromboembolism (VTE) represents one of the leading causes of death during pregnancy. The greatest risk for it is the presence of medical or family history of VTE, stillbirth, cesarean section and selected thrombophilia. Appropriate thromboprophylaxis has the potential to decrease the risk of VTE in at-risk pregnant patients by 60-70%. Based on this, the authors reviewed the PubMed, Web of Science and Scopus databases to identify the possibilities of thromboprophylaxis in pregnant patients with a high risk of VTE. Moreover, they summarized its management in specific situations, such as cesarean delivery or neuraxial blockade. Currently, low-molecular-weight heparins (LMWH) are the preferred drugs for anticoagulant thromboprophylaxis in the course of pregnancy and postpartum due to easy administration and a lower rate of adverse events.

Maternal and Newborn Characteristics-A Comparison between Healthy and Thrombophilic Pregnancy

A thrombophilic woman is more likely to experience difficulties during pregnancy, difficulties that will also affect the development of the newborn. This study aims to compare maternal and newborn characteristics between healthy and thrombophilic pregnancy. The following characteristics were analysed: maternal characteristics (BMI- body mass index, haemostasis parameters, thrombophilia-specific treatment) and newborn characteristics (gestational period, birth weight, the Apgar score). This follow-up study spanning five years, from 2018 to 2022, focuses on a cohort of 500 women who underwent delivery hospitalization in the western region of Romania. The maternal characteristics influence the newborn: the greater the weight of the mother with thrombophilia, the more the chances that the fetus will have a lower birth weight; increasing the dose of LMWH (low molecular weight heparin), connected with the necessity to control the homeostasis parameters, the more likely the fetus will be born with a lower birth weight. A pregnant woman with thrombophilia, treated appropriately, having a normal weight, and not presenting other risk factors independent of thrombophilia, will have a newborn with characteristics similar to a healthy pregnant woman.

Clinical risk factors for vasculo-placental disorders: results from a prospective case-control study nested in HEMOTHEPP French cohort study

OBJECTIVE

Determine clinical risk factors for vasculo-placental disorders in singleton pregnancies.

DESIGN

Prospective case-control study nested in HEMOTHEPP French cohort.

SETTING

Women delivered between June, 2015 and January, 2019 in any maternity ward of Finistère.

POPULATION

Cases were women with vasculo-placental disorders (pre-eclampsia, intrauterine growth restriction (IUGR), placental abruption or stillbirth). Controls were women matched for age at delivery and parity.

METHODS

Clinical data were collected by obstetricians or midwives during antenatal care visits and delivery, and recorded by trained research assistants.

MAIN OUTCOME MEASURES

Occurrence of a vasculo-placental disorder.

RESULTS

505 women with vasculo-placental disorder (299 pre-eclampsia, 253 IUGR, 44 placental abruptions, 11 stillbirths) and 1515 matched controls were selected out of 20,075 participants. In multivariable analysis, four clinical parameters were associated with pre-eclampsia: obesity (Odd ratio (OR) = 3.11, 95%CI 2.11-4.58), French overseas origin (OR = 4.41, 95%CI 1.87-10.42), previous vasculo-placental disorder (OR = 5.14, 95%CI 2.72-9.70), aspirin during pregnancy (OR = 10.10, 95%CI 1.99-51.08). Three clinical parameters were associated with IUGR: auto-immune/inflammatory disorder (OR = 3.75, 95%CI 1.83-7.68), previous vasculo-placental disorder (OR = 3.63, 95%CI 2.06-6.41), smoking during pregnancy (OR = 2.66, 95%CI 1.91- 3.71). A previous venous thromboembolism (VTE) was associated with IUGR in univariable but not in multivariable analysis (OR = 3.72, 95%CI 0.82-17.00, p = 0.09).

CONCLUSIONS

Clinical risk factors differ between IUGR and pre-eclampsia, the later, but not the former, being associated with cardiovascular risk factors.

Functionally integrating nanoparticles alleviate deep vein thrombosis in pregnancy and rescue intrauterine growth restriction

There is still unmet demand for effective, safe, and patient-friendly anti-thrombotics to treat deep vein thrombosis (DVT) during pregnancy. Here we first engineer a bioactive amphiphile (TLH) by simultaneously conjugating Tempol and linoleic acid onto low molecular weight heparin (LMWH), which can assemble into multifunctional nanoparticles (TLH NP). In pregnant rats with DVT, TLH NP can target and dissolve thrombi, recanalize vessel occlusion, and eradicate the recurrence of thromboembolism, thereby reversing DVT-mediated intrauterine growth restriction and delayed development of fetuses. Mechanistically, therapeutic effects of TLH NP are realized by inhibiting platelet aggregation, facilitating thrombolysis, reducing local inflammation, attenuating oxidative stress, promoting endothelial repair, and increasing bioavailability. By decorating with a fibrin-binding peptide, targeting efficiency and therapeutic benefits of TLH NP are considerably improved. Importantly, LMWH nanotherapies show no toxicities to the mother and fetus at the dose 10-time higher than the examined therapeutic dosage.

PREGNANCY AFTER COMBINED ORAL CONTRACEPTIVE-ASSOCIATED VENOUS THROMBOEMBOLISM: AN INTERNATIONAL RETROSPECTIVE STUDY OF OUTCOMES

BACKGROUND

Few data are available on thrombotic outcomes during pregnancy and puerperium occurring after an initial provoked venous thromboembolic event (VTE).

OBJECTIVES

To describe thrombotic outcomes during pregnancy after a first combined oral contraceptive (COC)-associated VTE and the factors associated with recurrence Methods. This was an international multicentric retrospective study on patients referred for thrombophilia screening from January 1st 2010 to January 1st 2021 following a first COC-associated VTE, including women with neither inherited thrombophilia nor antiphospholipid antibodies and focusing on those who had a subsequent pregnancy under the same thromboprophylaxis treatment. Thrombotic recurrences during pregnancy and puerperium as well as risk factors for recurrence were analysed.

RESULTS

We included 2,145 pregnant women. A total of 88 thrombotic events, 58 antenatal and 29 postnatal, occurred, mostly during the first trimester of pregnancy and the first two weeks of puerperium. Incidence rates were 49.6 (37-62) per 1,000 patient-years during pregnancy and 118.7 (78-159) per 1,000 patient-years during puerperium. Focusing on pulmonary embolism, incidence rates were 1.68 (1-4) per 1,000 patient-years during pregnancy and 65.5 (35-97) per 1,000 patient-years during puerperium. Risk factors for antenatal recurrences were maternal hypercholestorolaemia and birth of a very small-for-gestational-age neonate. A risk factor for postnatal recurrence was the incidence of preeclampsia. Conclusions Our multicentric retrospective data show significant rates of VTE recurrence during pregnancy and puerperium in women with a previous VTE event associated with COC, despite a unique LMWH-based thromboprophylaxis. These results may provide benchmarks and valuable information for designing future randomized controlled trials.

Preventing Postpartum Venous Thromboembolism in 2022: A Narrative Review

The postpartum period represents the most critical time for pregnancy-associated venous thromboembolism (VTE), which is responsible for substantial morbidity and an important cause of maternal mortality. The estimated risk of postpartum VTE of about 1/1,000 deliveries can be modulated with the knowledge of maternal and obstetrical risk factors, although a precise estimate remains challenging in individuals. The use of postpartum low-dose low-molecular-weight heparins are tailored at intermediate and high-risk groups to reduce the thrombotic burden, despite the lack of dedicated randomized controlled trials. In this review, we will highlight the contemporary evidence on the risk of postpartum VTE, its stratification and its prevention. We will also discuss our knowledge on the values and preferences of women for postpartum thromboprophylaxis and their adherence to treatment.

Association Between Maternal Weight Gain in Different Periods of Pregnancy and the Risk of Venous Thromboembolism: A Retrospective Case-Control Study

BACKGROUND

Venous thromboembolism (VTE) remains an important cause of maternal deaths. Little is known about the associations of specific periods of gestational weight gain (GWG) with the category of VTE, pulmonary embolism (PE), or deep venous thrombosis (DVT) with or without PE.

METHODS

In a retrospective case-control study conducted in Shanghai First Maternity and Infant Hospital from January 1, 2017 to September 30, 2021, cases of VTE within pregnancy or the first 6 postnatal weeks were identified. Controls without VTE were randomly selected from women giving birth on the same day as the cases, with 10 controls matched to each case. Total GWG and rates of early, mid, and late GWG values were standardized into z-scores, stratified by pre-pregnant body mass index (BMI). The adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were estimated through multivariate logistic regression models.

RESULTS

There were 196 cases (14.4 per 10,000) of VTE within pregnancy or the first 6 postnatal weeks were identified. Higher total weight gain was associated with increased risks of PE (aOR, 13.22; 95% CI, 2.03-85.99) and VTE (OR, 10.49; 95% CI, 1.82-60.45) among women with underweight. In addition, higher total weight gain was associated with increased risk of PE (aOR, 2.06; 95% CI, 1.14-3.72) among women with healthy weight. Similarly, rate of higher early weight gain was associated with significantly increased risk for PE (aOR, 2.15; 95% CI, 1.05-4.42) among women with healthy BMI. The lower rate of late weight gain was associated with increased risks of PE (aOR, 7.30; 95% CI, 1.14-46.55) and VTE (OR, 7.54; 95% CI, 1.20-47.57) among women with underweight. No significant associations between maternal rate of mid GWG and increased risk for any category of VTE, PE, or DVT with or without PE were present, regardless of maternal pre-pregnant BMI.

CONCLUSION

The GWG associations with the category of VTE, PE, or DVT with or without PE differ at different periods of pregnancy. In order to effectively improve maternal and child outcomes, intensive weight management that continues through pregnancy may be indispensable.

Risk factors for pregnancy-associated venous thromboembolism in Singapore

OBJECTIVES

Pregnancy-associated venous thromboembolism (VTE), including deep venous thrombosis (DVT) and pulmonary embolism (PE), is associated with increased risk of maternal mortality and morbidity. This study aimed to assess potential risk factors for pregnancy-associated VTE.

METHODS

In this case-control study, women with pregnancy-associated VTE were identified via International Classification of Diseases codes and included if they had been objectively diagnosed with VTE during pregnancy or within six weeks postpartum, from 2004 to 2016, at KK Women's and Children's Hospital or Singapore General Hospital in Singapore. Controls, i.e. pregnant women without VTE, were selected from a prospective longitudinal study. The odds ratio (OR) for VTE was computed for a range of maternal and obstetric factors.

RESULTS AND CONCLUSIONS

From 2004 to 2016, 89 cases of pregnancy-associated VTE and 926 controls were identifed and analysed using logistic regression. The most significant risk factors for pregnancy-associated VTE were smoking (OR 5.44, p=0.0002) and preterm delivery (OR 5.06, p=0.023). Malay race, multiparity, non-O blood group and caesarean section, were also identified to be of higher risk. These risk factors should be useful in the development of thromboprophylaxis strategies for pregnancy and the postpartum period, especially in Singapore.

Preventing postpartum venous thromboembolism: A call to action to reduce undue maternal morbidity and mortality

Postpartum venous thromboembolism (VTE) is a leading cause of maternal mortality in developed countries and can carry significant long-term morbidity. Despite being able to identify postpartum VTE risk factors in a large proportion of the obstetrical population, there is little high-quality evidence available to guide practice on who should receive postpartum thromboprophylaxis. Based on epidemiological data, women with a prior history of VTE or known potent thrombophilia are likely to benefit from an extended duration of low-molecular-weight heparin (LMWH) prophylaxis. However, significant controversy exists around the benefit and harm of postpartum thromboprophylaxis in women with more modest risk factors, such as those with mild thrombophilias or transient situational risk factors around labor and delivery, such as cesarean delivery. We review the available data for postpartum VTE risk factors and thromboprophylaxis in these patients. This review highlights the latest evidence in the area of postpartum VTE prevention, and is a call to action for further research in this area to improve maternal morbidity and mortality.

American Society of Hematology 2018 guidelines for management of venous thromboembolism: venous thromboembolism in the context of pregnancy

BACKGROUND

Venous thromboembolism (VTE) complicates ∼1.2 of every 1000 deliveries. Despite these low absolute risks, pregnancy-associated VTE is a leading cause of maternal morbidity and mortality.

OBJECTIVE

These evidence-based guidelines of the American Society of Hematology (ASH) are intended to support patients, clinicians and others in decisions about the prevention and management of pregnancy-associated VTE.

METHODS

ASH formed a multidisciplinary guideline panel balanced to minimize potential bias from conflicts of interest. The McMaster University GRADE Centre supported the guideline development process, including updating or performing systematic evidence reviews. The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to assess evidence and make recommendations.

RESULTS

The panel agreed on 31 recommendations related to the treatment of VTE and superficial vein thrombosis, diagnosis of VTE, and thrombosis prophylaxis.

CONCLUSIONS

There was a strong recommendation for low-molecular-weight heparin (LWMH) over unfractionated heparin for acute VTE. Most recommendations were conditional, including those for either twice-per-day or once-per-day LMWH dosing for the treatment of acute VTE and initial outpatient therapy over hospital admission with low-risk acute VTE, as well as against routine anti-factor Xa (FXa) monitoring to guide dosing with LMWH for VTE treatment. There was a strong recommendation (low certainty in evidence) for antepartum anticoagulant prophylaxis with a history of unprovoked or hormonally associated VTE and a conditional recommendation against antepartum anticoagulant prophylaxis with prior VTE associated with a resolved nonhormonal provoking risk factor.

Early Postpartum Venous Thromboembolism: Risk Factors and Predictive Index

The aim of our study was to quantify risk factors for venous thromboembolism (VTE) during the puerperal period. The case-control study was conducted in Women's Hospital, Zhejiang University, China, from January 2006 to December 2016; cases of hospitalized VTE within 1 week after delivery were identified according to International Classification of Diseases, Ninth Revision, Clinical Modification codes. Control postpartum women without VTE were randomly selected, matched on birth day, age, delivery mode, and number of fetus with 4:1 ratio. Clinical risk factors for postpartum VTE and coagulation parameters were analyzed. We found independent variables that were significantly related to postpartum VTE (all P < .05) in a binary logistic regression analysis included preeclampsia/eclampsia (odds ratio [OR], 2.89; 95% confidence interval [CI], 1.56-5.37) and postpartum hemorrhage (OR, 4.6; 95% CI, 1.71-12.40). D-dimer was the only biomarker that statistically significant associated with postpartum VTE in 3 days after delivery (all P < .05). These findings showed preeclampsia/eclampsia and postpartum hemorrhage were important risk factors for early VTE during puerperal period. A higher level of D-dimer was more meaningful than other coagulation parameters to suspect early thrombotic disease after delivery.

Passive smoking and stroke in men and women: a national population-based case-control study in China

An association between passive smoking and stroke is unclear in China, particularly the association with hemorrhagic stroke. This study included 16205 deaths due to stroke aged ≥30 years and 16205 non-stroke controls randomly selected and frequency-matched to cases on gender and age. Smoking of spouses, defined as ≥1 cigarette per day for up to 1 year, was taken as a measure of exposure to passive smoking of subjects that was retrospectively ascertained by interviewing surviving spouses. After adjustment for variables, passive smoking increased the risk of death by 10% (odds ratio (OR), 1.10; 95% confidence interval (CI), 1.05-1.16) for all strokes, by 10% (OR, 1.10; 95% CI, 1.04-1.16) for hemorrhagic stroke, and by 12% (OR, 1.12; 95% CI, 1.03-1.23) for ischemic stroke, compared with non-exposure. This finding was highly consistent in men or women and in smokers or non-smokers, and was generally consistent among zones of China despite geographic diversity. The risk significantly increased with exposure-years and quantity of cigarettes smoked daily by spouses. This study indicated that passive smoking is associated with deaths from all-type strokes. It is highly advisable for the government to promote strong tobacco prevention and cessation programs and smoke-free environments.

Development and validation of risk prediction model for venous thromboembolism in postpartum women: multinational cohort study

OBJECTIVE

 To develop and validate a risk prediction model for venous thromboembolism in the first six weeks after delivery (early postpartum).

DESIGN

 Cohort study.

SETTING

 Records from England based Clinical Practice Research Datalink (CPRD) linked to Hospital Episode Statistics (HES) and data from Sweden based registry.

PARTICIPANTS

 All pregnant women registered with CPRD-HES linked data between 1997 and 2014 and Swedish medical birth registry between 2005 and 2011 with postpartum follow-up.

MAIN OUTCOME MEASURE

 Multivariable logistic regression analysis was used to develop a risk prediction model for postpartum venous thromboembolism based on the English data, which was externally validated in the Swedish data.

RESULTS

 433 353 deliveries were identified in the English cohort and 662 387 in the Swedish cohort. The absolute rate of venous thromboembolism was 7.2 per 10 000 deliveries in the English cohort and 7.9 per 10 000 in the Swedish cohort. Emergency caesarean delivery, stillbirth, varicose veins, pre-eclampsia/eclampsia, postpartum infection, and comorbidities were the strongest predictors of venous thromboembolism in the final multivariable model. Discrimination of the model was similar in both cohorts, with a C statistic above 0.70, with excellent calibration of observed and predicted risks. The model identified more venous thromboembolism events than the existing national English (sensitivity 68% v 63%) and Swedish guidelines (30% v 21%) at similar thresholds.

CONCLUSION

 A new prediction model that quantifies absolute risk of postpartum venous thromboembolism has been developed and externally validated. It is based on clinical variables that are available in many developed countries at the point of delivery and could serve as the basis for real time decisions on obstetric thromboprophylaxis.

Pre-pregnancy BMI, delivery BMI, gestational weight gain and the risk of postpartum venous thrombosis

OBJECTIVE

To characterize the risk of postpartum venous thromboembolism (VTE) associated with body-mass-index (BMI) in both pre-pregnancy and at delivery, and with gestational weight gain (GWG).

METHODS

In a population-based, case-control study, we identified all women in Washington State with ICD-9 codes for VTE in the postpartum period between 2003 and 2011. Controls were women without VTE in the postpartum period, matched by delivery year to cases. Pre-pregnancy BMI, delivery BMI, and covariates were abstracted from birth certificates. Adjusted logistic regression models separately estimated postpartum VTE risk associated with categories of BMI in pre-pregnancy and at delivery.

RESULTS

Cases (n=289) had a higher mean BMI than controls (n=4208) pre-pregnancy (29.9kg/m(2) and 26.3kg/m(2), respectively) and at delivery (34.8kg/m(2) vs. 31.4kg/m(2), respectively), with similar gestational weight gains. Compared with women with a normal pre-pregnancy BMI (18.5-24.9kg/m(2)), overweight (BMI 25-29.9kg/m(2)) and obese (BMI≥30kg/m(2)) women were at a 1.5-fold and 1.8-4 fold greater risk of postpartum VTE, respectively, with greatest risks in women with class III obesity (BMI≥40kg/m(2): OR 4.0, 95%CI 2.7-6.3). Observed associations of delivery BMI with postpartum VTE were less strong than those of pre-pregnancy BMI. Large weight gains during pregnancy (>22kg) also contributed to greater VTE risks (OR 1.5, 95%CI 1.0-2.2).

CONCLUSION

Maternal BMI is an important risk factor for postpartum VTE, grading from weak in overweight women to very strong in women with class III obesity. Care providers may prefer to use pre-pregnancy BMI, along gestational weight gain, when stratifying the risk of postpartum VTE at delivery.

Cardiovascular Complications of Pregnancy

Pregnancy causes significant metabolic and hemodynamic changes in a woman's physiology to allow for fetal growth. The inability to adapt to these changes might result in the development of hypertensive disorders of pregnancy (hypertension, preeclampsia or eclampsia), gestational diabetes and preterm birth. Contrary to previous beliefs these complications are not limited to the pregnancy period and may leave permanent vascular and metabolic damage. There is in addition, a direct association between these disorders and increased risk of future cardiovascular disease (CVD, including hypertension, ischemic heart disease, heart failure and stroke) and diabetes mellitus. Despite abundant evidence of this association, women who present with these complications of pregnancy do not receive adequate postpartum follow up and counseling regarding their increased risk of future CVD. The postpartum period in these women represents a unique opportunity to intervene with lifestyle modifications designed to reduce the development of premature cardiovascular complications. In some cases it allows early diagnosis and treatment of chronic hypertension or diabetes mellitus. The awareness of this relationship is growing in the medical community, especially among obstetricians and primary care physicians, who play a pivotal role in detecting these complications and assuring appropriate follow up.