Estimated fetal weight standards of the INTERGROWTH-21st project for the prediction of adverse outcomes: a systematic review with meta-analysis.

OBJECTIVE: To systematically review and assess the risk of bias in the literature evaluating the performance of INTERGROWTH-21st estimated fetal weight (EFW) standards to predict maternal, fetal and neonatal adverse outcomes. METHODS: Searches were performed in seven electronic databases (Scopus, Web of Science, Medline, Embase, Lilacs, Scielo and Google Scholar) using citation tools and keywords (intergrowth AND (standard OR reference OR formula OR model OR curve); all from 2014 to the last search on April 16th, 2021). We included full-text articles investigating the ability of INTERGROWTH-21st EFW standards to predict maternal, fetal or neonatal adverse outcomes in women with a singleton pregnancy who gave birth to infants with no congenital abnormalities. The study was registered on PROSPERO under the number CRD42020115462. Risk of bias was assessed with a customized instrument based on the CHARMS checklist and composed of 9 domains. Meta-analysis was performed using relative risk (RR [95%CI]) and summary ROC curves on outcomes reported by two or more methodologically homogeneous studies. RESULTS: Sixteen studies evaluating fifteen different outcomes were selected. The risk of bias was high (>50% of studies with high risk) for two domains: blindness of assessment (81.3%) and calibration assessment (93.8%). Considering all the outcomes investigated, for 95% of the results, the specificity was above 73.0%, but the sensitivity was below 64.1%. Pooled results demonstrated a higher RR of neonatal small for gestational age (6.71 [5.51-8.17]), Apgar <7 at 5 min (2.17 [1.48-3.18]), and neonatal intensive care unit admission (2.22 [1.76-2.79]) for fetuses classified <10th percentile when compared to those classified above this limit. The limitation of the study is the absence of heterogeneity exploration or publication bias investigation, whereas no outcomes were evaluated by more than five studies. CONCLUSIONS: The IG-21 EFW standard has low sensitivity and high specificity for adverse events of pregnancy. Classification <10th percentile identifies a high-risk group for developing maternal, fetal and neonatal adverse outcomes, especially neonatal small for gestational age, Apgar <7 at 5 min, and neonatal intensive care unit admission. Future studies should include blind assessment of outcomes, perform calibration analysis with continuous data, and evaluate alternative cutoff points.

Comparison between the Brazilian and 3 international gestational weight gain charts.

BACKGROUND: Little is known about the ability of the recently released Brazilian gestational weight gain (GWG) charts to predict the occurrence of adverse birth outcomes. OBJECTIVES: We compared the new Brazilian weight gain charts with 3 international charts and determined their ability to predict the occurrence of small-for-gestational-age (SGA) and large-for-gestational-age (LGA) births in Brazilian women. METHODS: A subsample of 6888 adult women (43,931 weight measurements) with singleton pregnancies from a nationwide, hospital-based cohort study conducted in 2011-2012 was analyzed. Selected percentiles from Brazilian GWG charts were compared with those from American, International Fetal and Newborn Growth Consortium for the 21st Century study, and Lifecycle consortium charts. Sensitivity, specificity, and AUROC values for SGA and LGA births were estimated with 95% CIs using the classification of GWG below or above selected percentiles of each chart. RESULTS: The weight gain corresponding to a given percentile varied among the charts, especially for women with pre-pregnancy overweight and obesity. The proportions of women with GWG classified below or above selected percentiles were closest to the expected values for all pre-pregnancy BMI categories in the Brazilian and Lifecycle charts. At the 10th percentile, the highest sensitivity for SGA births was observed for the American charts at midpregnancy (36.8%) and the highest specificity was observed using the Brazilian charts in the first trimester (93.4%). At the 90th percentile, the highest sensitivity for LGA births occurred in midpregnancy for the Lifecycle charts (26.8%) and the highest specificity occurred in the American charts using total GWG (97.1%). All the AUROCs were under 0.5 for SGA births and ranged from 0.55 (first trimester) to 0.62 (total GWG) for LGA births. CONCLUSIONS: The charts differ in GWG trajectories, especially for women with overweight and obesity. The 4 charts had low predictive ability of SGA and LGA births and should not be considered as isolated screening tools for those outcomes.

Factors associated with longitudinal changes in B-vitamin and choline concentrations of human milk.

BACKGROUND: Little is known regarding the associations between maternal factors and B-vitamin and choline concentrations in early milk and the trajectories of these vitamins during lactation. OBJECTIVES: In this hypothesis-generating study, we modeled the association between maternal and offspring factors and longitudinal changes in milk B-vitamin and choline concentrations throughout lactation. METHODS: A hundred women were studied in a prospective birth cohort and milk samples from 52 women were collected at 2-8 d, 76 women at 28-50 d, and 42 women at 88-119 d postpartum. Maternal dietary intake during pregnancy and lactation was assessed by an FFQ. Linear mixed-effects models with interaction terms were used to evaluate changes in milk B-vitamin and choline concentrations over time based on maternal factors and the early postpartum concentrations of these micronutrients. RESULTS: The women with higher early postpartum milk concentrations of niacin (ßinteraction = -0.02; SE = 0.00; P < 0.001), pantothenic acid (ßinteraction = -0.10; SE = 2.56; P < 0.001), vitamin B-12 (ßinteraction= -0.10; SE = 0.03; P < 0.001), and choline (ßinteraction= -0.90; SE = 0.18; P < 0.001) exhibited a decrease in their concentrations throughout lactation. The participants with overweight and obesity prepregnancy experienced an increase in milk vitamin B-12 concentrations over time (ßinteraction = 0.04; SE = 0.02; P = 0.06). In contrast, a decrease in vitamin B-12 concentration was observed among women with vitamin B-12 intake below the RDA during pregnancy (ßinteraction= -0.08; SE = 0.05; P = 0.07). The women with niacin intake below the RDA during lactation experienced an increase in milk concentrations over time (ßinteraction = 0.01; SE = 0.01; P = 0.03). A gestational age at birth >40 wk was associated with an increase in milk choline concentration throughout lactation (ßinteraction = 0.54; SE = 0.16; P< 0.01). CONCLUSIONS: Changes in B-vitamin and choline concentrations in human milk over time may be associated with the early concentrations of these micronutrients in milk, maternal prepregnancy BMI, dietary intake, and gestational age at delivery.