暂无摘要。

This was an observational study of low-risk singleton pregnancies in an ethnic Chinese population. Foetal biometric variables which included biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC) and femur length (FL) were measured repeatedly. The standard views for measurement were obtained according to INTERGROWTH-21st criteria. A linear mixed model with fractional polynomial regression was used to describe the longitudinal design. The study included 1289 foetuses and a total of 5125 ultrasound scans, of which each foetus was scanned at least three times, the intervals between scans being at least two weeks. The parameters of the linear mixed models were estimated by Stata v.16 (College Station, TX). Using these parameters, the equations of the mean and variance for BPD, HC, AC and FL were constructed. The conditional percentiles or Z scores could be calculated based on the above equations and previous measurements of the same foetus. A spreadsheet was provided for implementation.Impact StatementWhat is already known on this subject? Longitudinal data derived from serial measurements are therefore appropriate for assessing both foetal size and foetal growth. At present, most reference charts of ethnic Chinese foetal biometry are derived from cross-sectional data, which can only assess foetal size.What do the results of this study add? In this study, we have constructed conditional standards for foetal biometry in an ethnic Chinese population and provided a spreadsheet for querying.What are the implications of these findings for clinical practice and/or further research? The conditional standards can be used to assess foetal growth in clinical practice. In the future, we hope that these foetal growth standards can be applied to determine whether abnormal growth increases the risk of adverse outcomes.

Severe iodine deficiency impacts fertility and reproductive outcomes. The potential effects of mild-to-moderate iodine deficiency are not well known. The aim of this study was to examine whether iodine intake was associated with subfecundity (i.e. > 12 months trying to get pregnant), foetal growth, and adverse pregnancy outcomes in a mild-to-moderately iodine-deficient population.
We used the Norwegian Mother, Father and Child Cohort Study (MoBa) and included 78,318 pregnancies with data on iodine intake and pregnancy outcomes. Iodine intake was calculated using an extensive food frequency questionnaire in mid-pregnancy. In addition, urinary iodine concentration was available in a subsample of 2795 pregnancies. Associations were modelled continuously by multivariable regression controlling for a range of confounding factors.
The median iodine intake from food was 121 μg/day and the median urinary iodine was 69 μg/L, confirming mild-to-moderate iodine deficiency. In non-users of iodine supplements (n = 49,187), low iodine intake (< 100-150 μg/day) was associated with increased risk of preeclampsia (aOR = 1.14 (95% CI 1.08, 1.22) at 75 vs. 100 μg/day, p overall < 0.001), preterm delivery before gestational week 37 (aOR = 1.10 (1.04, 1.16) at 75 vs. 100 μg/day, p overall = 0.003), and reduced foetal growth (- 0.08 SD (- 0.10, - 0.06) difference in birth weight z-score at 75 vs. 150 μg/day, p overall < 0.001), but not with early preterm delivery or intrauterine death. In planned pregnancies (n = 56,416), having an iodine intake lower than ~ 100 μg/day was associated with increased prevalence of subfecundity (aOR = 1.05 (1.01, 1.09) at 75 μg/day vs. 100 μg/day, p overall = 0.005). Long-term iodine supplement use (initiated before pregnancy) was associated with increased foetal growth (+ 0.05 SD (0.03, 0.07) on birth weight z-score, p < 0.001) and reduced risk of preeclampsia (aOR 0.85 (0.74, 0.98), p = 0.022), but not with the other adverse pregnancy outcomes. Urinary iodine concentration was not associated with any of the dichotomous outcomes, but positively associated with foetal growth (n = 2795, p overall = 0.017).
This study shows that a low iodine intake was associated with restricted foetal growth and a higher prevalence of preeclampsia in these mild-to-moderately iodine-deficient women. Results also indicated increased risk of subfecundity and preterm delivery. Initiating iodine supplement use in pregnancy may be too late.

To investigate the importance of time in pregnancy and neonatal sex on the association between maternal metabolic parameters and neonatal sum of skinfolds.
This was a longitudinal, secondary analysis of the vitamin D and lifestyle intervention for gestational diabetes mellitus study, conducted in nine European countries during 2012 to 2015. Pregnant women with a pre-pregnancy body mass index (BMI) of ≥29 kg/m2 were invited to participate. We measured 14 maternal metabolic parameters at three times during pregnancy: <20 weeks, 24 to 28 weeks, and 35 to 37 weeks of gestation. The sum of four skinfolds assessed within 2 days after birth was the measure of neonatal adiposity.
In total, 458 mother-infant pairs (50.2% female infants) were included. Insulin resistance (fasting insulin and HOMA-index of insulin resistance) in early pregnancy was an important predictor for boys\' sum of skinfolds, in addition to fasting glucose and maternal adiposity (leptin, BMI and neck circumference) throughout pregnancy. In girls, maternal lipids (triglycerides and fatty acids) in the first half of pregnancy were important predictors of sum of skinfolds, as well as fasting glucose in the second half of pregnancy.
Associations between maternal metabolic parameters and neonatal adiposity vary between different periods during pregnancy. This time-dependency is different between sexes, suggesting different growth strategies.

Pregnancy is characterised by a high rate of metabolic shifts from early to late phases of gestation in order to meet the raised physiological and metabolic needs. This change in levels of metabolites is influenced by gestational weight gain (GWG), which is an important characteristic of healthy pregnancy. Inadequate/excessive GWG has short-term and long-term implications on maternal and child health. Exploration of gestational metabolism is required for understanding the quantitative changes in metabolite levels during the course of pregnancy. Therefore, our aim is to study trimester-specific variation in levels of metabolites in relation to GWG and its influence on fetal growth and newborn anthropometric traits at birth.
A prospective longitudinal study is planned (start date: February 2018; end date: March 2023) on pregnant women that are being recruited in the first trimester and followed in subsequent trimesters and at the time of delivery (total 3 follow-ups). The study is being conducted in a hospital located in Bikaner district (66% rural population), Rajasthan, India. The estimated sample size is of 1000 mother-offspring pairs. Information on gynaecological and obstetric history, socioeconomic position, diet, physical activity, tobacco and alcohol consumption, depression, anthropometric measurements and blood samples is being collected for metabolic assays in each trimester using standardised methods. Mixed effects regression models will be used to assess the role of gestational weight in influencing metabolite levels in each trimester. The association of maternal levels of metabolites with fetal growth, offspring\'s weight and body composition at birth will be investigated using regression modelling.
The study has been approved by the ethics committees of the Department of Anthropology, University of Delhi and Sardar Patel Medical College, Rajasthan. We are taking written informed consent after discussing the various aspects of the study with the participants in the local language.

Acrylamide is a contaminant formed in a wide variety of carbohydrate-containing foods during frying or baking at high temperatures. Recent studies have suggested reduced foetal growth after exposure to high levels of acrylamide during pregnancy.
To study the relationship between maternal dietary acrylamide intake during pregnancy and their offspring\'s anthropometry at birth.
In our population of 1471 mother-child pairs from two French cities, Nancy and Poitiers, dietary acrylamide intake during pregnancy was assessed by combining maternal food frequency questionnaires with data on food contamination at the national level, provided by the second \"French Total Diet Study\". Newborns weighing less than the 10th percentile, according to a customised definition, were defined as small for gestational age (SGA). Linear and logistic regression models were used to study continuous and binary outcomes respectively, adjusting for the study centre, maternal age at delivery, height, education, parity, smoking during pregnancy, the newborn\'s gestational age at birth and sex.
The median and interquartile range of dietary acrylamide intake were 19.2μg/day (IQR, 11.8;30.3). Each 10μg/day increase in acrylamide intake was associated with an odds-ratio for SGA of 1.11 (95% Confidence Interval: 1.03,1.21), birth length change of -0.05cm (95% CI: -0.11,0.00) and birth weight change of -9.8g (95% CI: -21.3,1.7).
Our results, consistent with both experimental and epidemiological studies, add to the evidence of an effect of acrylamide exposure on the risk of SGA and suggest an effect on foetal growth, for both weight and length.