A systematic review and meta-analysis of the correlation between maternal and neonatal iron status and haematologic indices.

BACKGROUND: Iron deficiency (ID) is the leading single-nutrient deficiency in the world. Anaemia is a common outcome of ID that affects half of pregnancies worldwide with serious consequences for child development. Whether haematologic indices and biomarkers of iron status in pregnant women correlate with those of their neonates is unclear. This systematic review evaluated studies comparing haematologic and iron status indices in pregnant women and their newborns/neonates. METHODS: We searched MEDLINE, EMBASE, CINAHL, and Web of Science from database inception until March 2020 for primary studies comparing haematologic and iron status indices between women and their newborns up to 48 h after birth. We summarized the results descriptively and calculated pooled correlation coefficients in mothers and newborns/neonates using the Schmidt-Hunter method. The protocol was registered at PROSPERO International Prospective Register of Systematic Reviews (Registration number: CRD42018093094). FINDINGS: Sixty-five studies were included. Pooled correlation coefficients for biomarkers of iron status in mothers and newborns/neonates were 0.13 (ferritin), 0.42 (hepcidin), 0.30 (serum/plasma iron), 0.09 (transferrin), 0.20 (transferrin saturation), and 0.16 (total iron binding capacity). Pooled correlation coefficients for haematological indices in mothers and newborns/neonates were 0.15 (haemoglobin), 0.15 (haematocrit), 0.25 (mean cell/corpuscular haemoglobin), 0.22 (mean cell/corpuscular volume). INTERPRETATION: Maternal biomarkers of iron and haematologic status correlate poorly with those in newborns/neonates. These results underscore a need for alternative approaches to estimate foetal/neonatal iron status and haematological indices. FUNDING: MBO and SLB hold Canada Research Chairs, and grants from the Women and Children's Health Research Institute and Canadian Institutes of Health Research.

Prevalence of diabetes in pregnancy among Indigenous women in Australia, Canada, New Zealand, and the USA: a systematic review and meta-analysis.

BACKGROUND: Indigenous peoples in countries with similar colonial histories have disproportionate burdens of disease compared with non-Indigenous peoples. We aimed to systematically identify and collate studies describing the prevalence of pre-existing diabetes and gestational diabetes, and compare the prevalence of these conditions between Indigenous and non-Indigenous pregnant women in Australia, Canada, New Zealand, and the USA. METHODS: For this systematic review and meta-analysis, an information specialist did a comprehensive search of eight databases (Ovid MEDLINE, Ovid Embase, Ovid Global Health, CINAHL [EBSCO], Scopus, ProQuest Dissertations and Theses Global, PROSPERO, and the Wiley Cochrane Library) in June, 2019, for studies published between inception and June 25, 2019, without restrictions on language, publication type, or year of publication. Database searches were supplemented by grey literature searches of the Bielefield Academic Search Engine and Google Scholar, and the reference lists of relevant articles were also manually searched. We included observational epidemiological studies comparing the prevalence of pre-existing diabetes or gestational diabetes in Indigenous and non-Indigenous pregnant women in Australia, Canada, New Zealand, and the USA. Two independent reviewers assessed study eligibility and risk of bias. We used a standardised data extraction form to collect information from the published reports of eligible studies, and, if needed, we contacted authors for further information. We did a Mantel-Haenszel random-effects meta-analysis to obtain the pooled unadjusted prevalence odds ratios (PORs) of pre-existing diabetes and gestational diabetes in Indigenous women compared with non-Indigenous women. We stratified meta-analyses by country and type of diabetes. The study is registered with PROSPERO, number CRD42018095971. FINDINGS: Our search identified 1348 studies, of which 43 studies with 32 952 441 participants from Australia, Canada, New Zealand, and the USA were included in the systematic review, and 39 of these studies were included in the meta-analysis. 40 of the included studies used a cohort design. Pre-existing diabetes was more prevalent in Indigenous women than in non-Indigenous women, with pooled PORs ranging from 1·81 (95% CI 1·53-2·13) for women in the USA to 3·63 (2·35-5·62) for women in Australia. Similarly, gestational diabetes was more prevalent in Indigenous women than in non-Indigenous women, with PORs ranging from 1·42 (1·24-1·63) for women in Australia to 2·04 (1·46-2·84) for women in Canada. Risk of bias was low in 37·2% of studies, unclear in 34·8% of studies, and high in 27·9% of studies. Heterogeneity between studies was predominantly high (I2=97-100%), with one exception of moderate heterogeneity (I2=48%); however, the magnitude and direction of the PORs from individual studies indicated an association between pre-existing diabetes or gestational diabetes and indigeneity among pregnant women. INTERPRETATION: The prevalence of pre-existing diabetes and gestational diabetes was higher in Indigenous pregnant women than in non-Indigenous pregnant women in four countries (Australia, Canada, New Zealand and the USA) with similar histories of colonialism. These findings have implications for prenatal care services and the monitoring of Indigenous women in industrialised countries. FUNDING: Canadian Institute of Health Research and the Women's and Children's Health Research Institute.

Systematic review of the measurement properties of indices of prenatal care utilization.

BACKGROUND: An accurate assessment of the adequacy of prenatal care utilization is critical to inform the relationship between prenatal care and pregnancy outcomes. This systematic review critically appraises the evidence on measurement properties of prenatal care utilization indices and provides recommendations about which index is the most useful for this purpose. METHODS: MEDLINE, EMBASE, CINAHL, and Web of Science were systematically searched from database inception to October 2018 using keywords related to indices of prenatal care utilization. No language restrictions were imposed. Studies were included if they evaluated the reliability, validity, or responsiveness of at least one index of adequacy of prenatal care utilization. We used the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) checklist. We conducted an evidence synthesis using predefined criteria to appraise the measurement properties of the indices. RESULTS: From 2664 studies initially screened, 13 unique studies evaluated the measurement properties of at least one index of prenatal care utilization. Most of the indices of adequacy of prenatal care currently used in research and clinical practice have been evaluated for at least some form of reliability and/or validity. Evidence about the responsiveness to change of these indices is absent from these evaluations. The Adequacy Perinatal Care Utilization Index (APNCUI) and the Kessner Index are supported by moderate evidence regarding their reliability, predictive and concurrent validity. CONCLUSION: The scientific literature has not comprehensively reported the measurement properties of commonly used indices of prenatal care utilization, and there is insufficient research to inform the choice of the best index. Lack of strong evidence about which index is the best to measure prenatal care utilization has important implications for tracking health care utilization and for formulating prenatal care recommendations.

Alterations in vascular function by syncytiotrophoblast extracellular vesicles via lectin-like oxidized low-density lipoprotein receptor-1 in mouse uterine arteries.

Syncytiotrophoblast extracellular vesicles (STBEVs), released into the maternal circulation during pregnancy, have been shown to affect vascular function; however, the mechanism remains unknown. In rats, STBEVs were shown to reduce endothelium-mediated vasodilation via lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), a multi-ligand scavenger receptor that has been associated with vascular dysfunction. Recently, LOX-1 was shown to interact with the angiotensin II type 1 receptor (AT-1). We hypothesized that, in pregnant mice, STBEVs would impair vascular function via LOX-1 and would specifically affect angiotensin II responses. Uterine arteries from pregnant control (C57BL/6) and LOX-1 knockout (LOX-1KO) mice were isolated on gestational day (GD) 18.5. Endothelium-dependent (methylcholine (MCh); ± N(G)-Nitro-L-arginine methyl ester to assess nitric oxide (NO) contribution), and -independent (sodium nitroprusside) vasodilation, and vasoconstriction (angiotensin II; ± AT-1 [candesartan] or angiotensin II type 2 receptor (AT-2) [PD123.319] receptor antagonists; high potassium salt solution) responses were assessed using wire myography. AT-1 and AT-2 expression was analyzed using fluorescence microscopy. Human umbilical vein endothelial cells (HUVECs) were stimulated with STBEVs ± LOX-1 blocking antibody, and superoxide and peroxynitrite production were analyzed. Although MCh-induced vasodilation was decreased (P=0.0012), NO contribution to vasodilation was greater in LOX-1KO mice (P=0.0055). STBEVs delayed angiotensin II tachyphylaxis in arteries from control but not LOX-1KO mice (P<0.0001), while AT-1 and AT-2 expression was unchanged. STBEVs increased peroxynitrite production in HUVECs via LOX-1 (P=0.0091). In summary, LOX-1 deletion altered endothelium-mediated vasodilation, suggesting that LOX-1 contributes to vascular adaptations in pregnancy. STBEVs increased angiotensin II responsiveness and oxidative stress levels via LOX-1, suggesting that increased LOX-1 expression/activation or STBEVs could adversely affect vascular function and contribute to vascular complications of pregnancy.