Cause of intrauterine and neonatal death in twin pregnancies (CoDiT): development of a novel classification system

Risk factors for adverse outcomes in twin pregnancies: a narrative review

PURPOSE

Globally, the incidence of twin pregnancies is rising owing to the use of assisted reproductive technologies (ART), emigration and deferment of pregnancy until advanced maternal age (AMA). While twin pregnancies have higher absolute risks of adverse outcomes, including miscarriage, stillbirth, neonatal death and preterm delivery, the impact of specific exposures and risk factors related to these outcomes may differ between twin pregnancies and singleton pregnancies. Regarding modifiable factors, data are sometimes based on evidence extrapolated from singleton or whole obstetric populations. Therefore, targeted evidence is required to provide care tailored to twin pregnancies to prevent adverse outcomes. We aimed to comprehensively review the association between different risk factors and adverse outcomes in twin pregnancies, including data on chorionicity, and to compare these to singletons.

MATERIALS AND METHODS

This review examines the risks associated with chorionicity, AMA, body mass index (BMI), socioeconomic and ethnic inequalities, maternal smoking, use of ART, maternal perception of fetal movement, and maternal comorbidities, including hypertensive disorders of pregnancy (HDP) and gestational diabetes mellitus (GDM). Adverse outcomes reported were preterm birth, admission to the neonatal intensive care unit (NICU), stillbirth and neonatal mortality. As such, fetal mortality and morbidity will be under-represented, as pregnancy loss before 22-24 weeks is omitted.

RESULTS

Monochorionicity increases the risk of stillbirth, NICU admission, and preterm delivery in twin pregnancy. AMA predisposes twin pregnancies to higher risks of mortality, admission to the NICU, and preterm birth than singleton pregnancies do. Conversely, the impact of BMI, socioeconomic inequalities, smoking, ART, and HDP on adverse outcomes appears to be lower in twin pregnancies than in singleton pregnancies. This attenuation might be explained by the higher baseline risk of adverse outcomes such as preterm birth in twin pregnancies. Some exposures, such as ART use and GDM, appear to be "protective" against perinatal mortality in twin pregnancies, despite being established risk factors for adverse outcomes in singleton pregnancies, potentially related to access to specialist care. There is a paucity of evidence available to counsel mothers of twin pregnancies regarding reduced fetal movement.

CONCLUSIONS

Overall, the risk factors for adverse pregnancy outcomes differ between twin and singleton pregnancies. This highlights the need for further studies to examine the association between risk factors and adverse outcomes in twin pregnancies. The resulting data would facilitate tailored guidance for twin pregnancies, contribute to improved antenatal care, and inform wider public health strategies.

Stillbirth diagnosis and classification: comparison of ReCoDe and ICD-PM systems

OBJECTIVES

The identification of causes of stillbirth (SB) can be a challenge due to several different classification systems of SB causes. In the scientific literature there is a continuous emergence of SB classification systems, not allowing uniform data collection and comparisons between populations from different geographical areas. For these reasons, this study compared two of the most used SB classifications, aiming to identify which of them should be preferable.

METHODS

A total of 191 SBs were retrospectively classified by a panel composed by three experienced-physicians throughout the ReCoDe and ICD-PM systems to evaluate which classification minimizes unclassified/unspecified cases. In addition, intra and inter-rater agreements were calculated.

RESULTS

ReCoDe defined: the 23.6% of cases as unexplained, placental insufficiency in the 14.1%, lethal congenital anomalies in the 12%, infection in the 9.4%, abruptio in the 7.3%, and chorioamnionitis in the 7.3%. ICD-PM defined: the 20.9% of cases as unspecified, antepartum hypoxia in the 44%, congenital malformations, deformations, and chromosomal abnormalities in the 11.5%, and infection in the 11.5%. For ReCoDe, inter-rater was agreement of 0.58; intra-rater agreements were 0.78 and 0.79. For ICD-PM, inter-rater agreement was 0.54; intra-rater agreements were of 0.76 and 0.71.

CONCLUSIONS

There is no significant difference between ReCoDe and ICD-PM classifications in minimizing unexplained/unspecified cases. Inter and intra-rater agreements were largely suboptimal for both ReCoDe and ICD-PM due to their lack of specific guidelines which can facilitate the interpretation. Thus, the authors suggest correctives strategies: the implementation of specific guidelines and illustrative case reports to easily solve interpretation issues.

The fetus in the age of the genome

Due to a number of recent achievements, the field of prenatal medicine is now on the verge of a profound transformation into prenatal genomic medicine. This transformation is expected to not only substantially expand the spectrum of prenatal diagnostic and screening possibilities, but finally also to advance fetal care and the prenatal management of certain fetal diseases and malformations. It will come along with new and profound challenges for the normative framework and clinical care pathways in prenatal (and reproductive) medicine. To adequately address the potential ethically challenging aspects without discarding the obvious benefits, several agents are required to engage in different debates. The permissibility of the sequencing of the whole fetal exome or genome will have to be examined from a philosophical and legal point of view, in particular with regard to conflicts with potential rights of future children. A second requirement is a societal debate on the question of priority setting and justice in relation to prenatal genomic testing. Third, a professional-ethical debate and positioning on the goal of prenatal genomic testing and a consequential re-structuring of clinical care pathways seems to be important. In all these efforts, it might be helpful to envisage the unborn rather not as a fetus, not as a separate moral subject and a second "patient", but in its unique physical connection with the pregnant woman, and to accept the moral quandaries implicitly given in this situation.