Objective

This study aimed to assess the rate of adverse obstetrical and neonatal outcomes in pregnancies diagnosed with confined placental mosaicism relative to that of unaffected controls.

Data Sources

Web-based databases were searched using relevant key words, and articles published from 1980 to February 2022 were retrieved.

Study Eligibility Criteria

Observational studies in English language including ≥10 cases of singleton pregnancies with diagnosis of confined placental mosaicism were included. The diagnosis was established after detection of any chromosomal abnormality at chorionic villus sampling for any indication, followed by normal karyotype from amniotic fluid or neonatal leukocyte culture.

Methods

Two authors independently screened the references for eligibility, data extraction, and assessment of methodological quality using the Newcastle–Ottawa scale. All available obstetrical and neonatal outcomes were recorded. Random-effect meta-analysis was performed to estimate pooled odds ratios and 95% confidence intervals of available outcomes in pregnancies with and without confined placental mosaicism. Statistical heterogeneity was evaluated with I² statistics (International Prospective Register of Systematic Reviews registration number: CRD42021260319).

Results

Of the 80 articles reviewed, 8 retrospective matched-cohort studies (708 cases of confined placental mosaicism and 11,599 unaffected controls) compared cases with and without confined placental mosaicism and were included in the meta-analysis.

The risk of delivering small-for-gestational-age neonates was significantly increased in confined placental mosaicism pregnancies according to crude analysis (odds ratio, 2.45; 95% confidence interval, 1.23–4.89; I²=72%) and to sensitivity analysis of high-quality studies (odds ratio, 3.65; 95% confidence interval, 2.43–5.57; I²=0%). Similarly, confined placental mosaicism resulted in an increased risk of birthweight below the third centile (odds ratio, 5.33; 95% confidence interval, 1.19–24.19; I²= 83%). Subgroup analysis revealed that the risk of delivering small-for-gestational-age neonates was 3-fold higher for confined placental mosaicism excluding trisomy 16, and 11-fold higher for cases including trisomy 16 only vs unaffected controls, respectively. No difference was found in the risk of low birthweight and preterm birth (at <37 weeks’ gestation). Other outcomes were insufficiently reported, therefore they were not analyzed.

Conclusion

Pregnant women prenatally diagnosed with confined placental mosaicism have an increased risk of impaired fetal growth, suggesting the need for intensified antenatal surveillance.

中文翻译：

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局限性胎盘嵌合体的妊娠结局：队列研究的荟萃分析

客观的

本研究旨在评估诊断为局限性胎盘嵌合体的妊娠相对于未受影响的对照组的不良产科和新生儿结局的发生率。

数据源

使用相关关键词检索网络数据库，检索1980年至2022年2月发表的文章。

学习资格标准

纳入了英语观察性研究，包括 ≥10 例诊断为局限性胎盘嵌合体的单胎妊娠病例。在绒毛膜绒毛取样中检测到任何染色体异常，然后从羊水或新生儿白细胞培养物中检测到正常核型后，即可做出诊断。

方法

两位作者使用纽卡斯尔-渥太华量表独立筛选参考文献的资格、数据提取和方法学质量评估。记录所有可用的产科和新生儿结局。进行随机效应荟萃分析，以估计有或没有局限性胎盘嵌合的妊娠中可用结果的汇总比值比和 95% 置信区间。使用I ²统计数据评估统计异质性（国际前瞻性系统评价注册登记号：CRD42021260319）。

结果

在审查的 80 篇文章中，8 项回顾性匹配队列研究（708 例局限性胎盘嵌合病例和 11,599 例未受影响的对照）比较了有和没有局限性胎盘嵌合的病例，并纳入荟萃分析。

根据粗略分析（比值比，2.45；95% 置信区间，1.23–4.89； I ² =72%）和敏感性分析，胎盘嵌合妊娠中生出小于胎龄新生儿的风险显着增加。高质量研究（比值比，3.65；95% 置信区间，2.43–5.57；I ² =0%）。同样，局限性胎盘嵌合导致出生体重低于第三个百分位数的风险增加（比值比，5.33；95% 置信区间，1.19–24.19；I ² = 83%）。亚组分析显示，与未受影响的对照组相比，不包括 16 三体性的局限性胎盘嵌合体的产下小于胎龄新生儿的风险分别高出 3 倍，仅包括 16 三体性的病例的产下小于胎龄新生儿的风险分别高出 11 倍。低出生体重和早产（妊娠<37周）的风险没有差异。其他结果报告不充分，因此未进行分析。

结论

产前诊断为局限性胎盘嵌合体的孕妇胎儿生长受损的风险增加，表明需要加强产前监测。