Human embryonic curvature studied with 3D ultrasound in ongoing pregnancies and miscarriages.

Embryonic growth is often impaired in miscarriages. It is postulated that derangements in embryonic growth result in abnormalities of the embryonic curvature. This study aims to create first trimester reference charts of the human embryonic curvature and investigate differences between ongoing pregnancies and miscarriages. Weekly ultrasonographic scans from ongoing pregnancies and miscarriages were used from the Rotterdam periconceptional cohort and a cohort of recurrent miscarriages. In 202 ongoing pregnancies and 33 miscarriages, first trimester crown rump length and total arch length were measured to assess the embryonic curvature. The results show that the total arch length increases and shows more variation with advanced gestation. The crown rump length/total arch length ratio shows a strong increase from 8+0 to 10+0 weeks and flattening thereafter. No significant difference was observed between the curvature of embryos of ongoing pregnancies and miscarriages. The majority of miscarried embryos could not be measured. Therefore, this technique is too limited to recommend the measurement of the embryonic curvature in clinical practice.

Human embryonic growth trajectories and associations with fetal growth and birthweight.

STUDY QUESTION: How do human embryonic growth trajectories evolve in the first trimester, and is first-trimester embryonic growth associated with fetal growth and birthweight (BW)? SUMMARY ANSWER: Human embryonic growth rates increase between 9 and 10 weeks of gestation and are associated with mid-pregnancy fetal growth and BW. WHAT IS KNOWN ALREADY: Fetal growth is associated with health and disease risks in later life. Until recently, prenatal care and research have been focused predominantly on fetal growth in the second and third trimesters of pregnancy. Longitudinal first-trimester data remain scarce. STUDY DESIGN, SIZE, DURATION: We recruited 201 pregnancies before 8 weeks of gestation in a prospective periconception cohort study conducted in a tertiary center. PARTICIPANTS/MATERIALS, SETTING, METHODS: We performed weekly 3D ultrasound scans from enrollment up to 13 weeks of gestation. To create embryonic growth trajectories, serial crown-rump length (CRL) measurements were performed using the V-Scope software in the BARCO I-Space. Mid-pregnancy fetal growth parameters and BW were obtained from medical records. Z-scores were calculated for CRL, mid-pregnancy estimated fetal weight (EFW) and BW. Associations between embryonic and fetal growth parameters were investigated using Pearson's correlation coefficients. MAIN RESULTS AND THE ROLE OF CHANCE: During the early first trimester (up to 9 weeks of gestation), we observed a constant absolute mean embryonic CRL growth rate of 0.99 mm/day (SD 0.10), while the relative growth rate decreased. Between 9 and 10 weeks of gestation, the absolute growth rate increased, and during late first trimester (from 10 weeks of gestation onward), we observed a constant mean relative growth rate of 4.1% (SD 0.006) per day. Overall, early and late first-trimester median CRL Z-scores were strongly correlated with mid-pregnancy EFW (r overall/early/late = 0.57/0.57/0.54, P < 0.001) but only overall and late CRL Z-scores were correlated with BW (r overall = 0.15, P = 0.04; r early = 0.10, P = 0.17; r late = 0.17, P = 0.02). LIMITATIONS, REASONS FOR CAUTION: This study was conducted in a tertiary hospital. Therefore, future studies in other populations are warranted to confirm our results. WIDER IMPLICATIONS OF THE FINDINGS: This study shows differences between early and late first-trimester embryonic growth coinciding with changes in intrauterine nourishment. The established associations between first-trimester embryonic growth and fetal size in mid-pregnancy and at birth emphasize that more research is warranted to establish the importance of these results for preconceptional and early pregnancy care.

Influence of maternal folate status on human fetal growth parameters.

Worldwide periconceptional folic acid supplement use is recommended to prevent neural tube defects. This also stimulated research on maternal folate status in association with fetal growth, an important predictor of perinatal and future development and health. We provide an overview of literature on associations between maternal folate status during pregnancy determined by folate biomarker concentrations in blood, folic acid supplement use and dietary folate intake, and fetal growth parameters. Literature was searched in PubMed up to November 2011. Some studies suggest inverse associations between serum folate, folic acid supplement use and dietary folate intake and risk of a low birth weight or small for gestational age infant. The strongest evidence, however, revealed positive associations between birth weight and red blood cell folate, folic acid supplement use and dietary folate intake. Red blood cell folate appeared to be most consistently associated with other fetal growth parameters. These findings contribute to the knowledge of the impact of maternal folate status on fetal growth, and subsequently perinatal health and disease risks in later life. Future research is recommended to examine effects of windows, duration and dose of folic acid supplement use and use of folate-rich dietary patterns in different populations on fetal growth parameters.