The association of inherited thrombophilia and intrauterine fetal death: a case–control study

Inherited thrombophilias and stillbirth: a systematic review and meta- analysis

PURPOSE

The association between inherited thrombophilias and stillbirth has been long investigated but the estimated risk remains unknown. The aim of our study is to summarize available data on the effect of Factor V Leiden, Prothrombin G20210A and MTHFR mutation, Protein S, Protein C and Anithrombin deficiency on the prevalence of stillbirth.

METHODS

We conducted a systematic review and meta- analysis of all relevant available PubMed, Embase and Cochrane studies until February 2024. A sensitivity analysis of only prospective and retrospective studies was performed.

RESULTS

Based on 31 included studies, Factor V Leiden and Prothrombin G202110A mutations, significantly rise the prevalence of stillbirth with a pooled OR 2.35 (95% CI 1.74-3.17) and 2.62 (95% CI 1.79-3.84), respectively. This positive correlation did not change in the sensitivity analysis. Positive correlation was also found between Antithrombin deficiency and stillbirth with a pooled OR 3.97 (95% CI 1.50-10.48). No statistically significant relationship was found between stillbirth and MTHFR mutation or Protein C and Protein S deficiency according to the random effects model.

CONCLUSION

Our findings suggest that in the presence of certain inherited thrombophilias, the occurrence of intrauterine fetal death is significantly more prevalent.

Association between pregravid physical activity and family history of stroke and risk of stillbirth: population-based cohort study

OBJECTIVES

To evaluate whether family history of disease and pregravid lifestyle and cardiovascular risk factors are associated with subsequent stillbirth delivery.

DESIGN

Prepregnancy cohort study.

SETTING

Cohort Norway regional health surveys (1994-2003) linked to Medical Birth Registry of Norway for deliveries through 2012.

PARTICIPANTS

13 497 singleton births (> 22 weeks gestation) in 8478 women.

MAIN OUTCOME MEASURE

Risk of stillbirth evaluated by Poisson regression.

RESULTS

Mean (SD) length of follow-up was 5.5 (3.5) years. In analyses adjusting for baseline age and length of follow-up, ≥3 hours of baseline past-year vigorous physical activity per week (resulting in shortness of breath/sweating) was associated with increased risk of stillbirth compared with <1 hour/week of vigorous activity (incidence rate ratio, IRR 2.46; 95% CI 1.23 to 4.90). In contrast, baseline past-year light physical activity of ≥3 hours per week associated with reduced risk of stillbirth compared with <3 hours of light physical activity per week (IRR 0.53; 95% CI 0.30 to 0.93). A family history of stroke associated with increased risk of stillbirth delivery (IRR 2.53; 95% CI 1.06 to 6.01). Because overweight/obese women may experience shortness of breath and sweating with less physical exertion than normal weight women, a sensitivity analysis was conducted limited to women with a normal BMI (> 18.5 and <25 kg/m²). Vigorous activity of ≥3 hours per week (IRR of 4.50; 95% CI 1.72 to 11.79) and a family history of stroke (IRR of 3.81; 95% CI 1.31 to 11.07) were more strongly related to stillbirth risk among women with a normal BMI than that observed for all women combined. Established risk factors also associated with stillbirth risk.

CONCLUSIONS

The study identified physical activity and family history of stroke as potential new risk factors for stillbirth delivery.

Perinatal death investigations: What is current practice?

Perinatal death (PD) is a devastating obstetric complication. Determination of cause of death helps in understanding why and how it occurs, and it is an indispensable aid to parents wanting to understand why their baby died and to determine the recurrence risk and management in subsequent pregnancy. Consequently, a perinatal death requires adequate diagnostic investigation. An important first step in the analysis of PD is to identify the case circumstances, including relevant details regarding maternal history, obstetric history and current pregnancy (complications are evaluated and recorded). In the next step, placental examination is suggested in all cases, together with molecular cytogenetic evaluation and fetal autopsy. Investigation for fetal-maternal hemorrhage by Kleihauer is also recommended as standard. In cases where parents do not consent to autopsy, alternative approaches such as minimally invasive postmortem examination, postmortem magnetic resonance imaging, and fetal photographs are good alternatives. After all investigations have been performed it is important to combine findings from the clinical review and investigations together, to identify the most probable cause of death and counsel the parents regarding their loss.

Classification of stillbirths and risk factors by cause of death--a case-control study

OBJECTIVE

To investigate risk factors for stillbirths by cause, using the Causes of Death and Associated Conditions (CODAC) classification system for perinatal deaths.

DESIGN

Case-control study.

SETTING

Two university hospitals in Oslo, Norway, January 1990 through December 2003.

SAMPLE

Women with stillbirth after 22 gestational weeks (n = 377) and controls with live births (n = 1 215), and a subsample of 105 cases and 262 controls.

METHODS

Socio-demographic, clinical and thrombophilic risk factors for stillbirths were assessed by cause of death in univariate and multivariable logistic regression analyses. Stillbirths were classified according to CODAC based on information from medical records and validated placenta histology.

MAIN OUTCOME MEASURES

Causes of stillbirths in percentages, prevalence, odds ratios and adjusted odds ratios for potential risk factors.

RESULTS

Approximately half of the women (n = 190) had placental and 19.4% (n = 73) unknown cause of stillbirth. Placental-associated conditions were registered in 18% (n = 68) of cases with a non-placental or an unknown cause. Smoking and small-for-gestational age were more prevalent in all causal groups, compared with controls, whereas twin pregnancy, hypertension and diabetes were more prevalent only among women with placental and unknown causes of stillbirth. The F2rs179963 polymorphism and combined thrombophilia were significant risk factors for stillbirth with placental causes and antiphospholipid antibodies for stillbirth with non-placental causes.

CONCLUSIONS

Two-thirds of all stillbirths (68%) were caused by or associated with placental pathology. Risk factors differed somewhat according to cause, apart from smoking and small-for-gestational age, which were significant risk factors across the causal groups.

[Hereditary thrombophilias and placental-mediated pregnancy complications in the II./III. trimester]

Placental-mediated pregnancy complications (PmC) like preeclampsia, intrauterine growth restriction and placental abruption are common causes of fetal and maternal morbidity and mortality. The high prevalence of hereditary thrombophilias in case-control studies associated with pathological morphological findings of the placenta in these cases gave evidence for the association between hereditary thrombophilias and PmC. However, data from the literature are inconsistent, since subsequent prospective cohort studies could not demonstrate significant associations between inherited thrombophilia and PmC. Because of the multifactorial aetiology of PmC it may be difficult to prove, that hereditary thrombophilias are independent risk factors for PmC. Current guidelines do not recommend screening for inherited thrombophilias in patients with previous PmC. Evidence from current in vitro studies have shown, that heparin has beneficial non-anticoagulatory effects on trophoblast invasion. Retrospective case-control studies and recently published randomised controlled cohort studies have shown, that prophylactic administration of low-molecular-weight heparin (LWH), started in early pregnancy, may lead to a significant reduction in the incidence of PmC in subsequent pregnancies in patients with and without hereditary thrombophilias and previous PmC.

CONCLUSION

Large, well-designed multicenter studies are needed to elucidate the role of hereditary thrombophilias in cases of PmC and to confirm the benefit of LWH for subsequent pregnancy outcomes.