Objective::To establish the Chinese population's amniotic fluid deepest vertical pocket (DVP) reference curves for dichorionic twin pregnancies and to investigate DVP links with adverse perinatal outcomes.Methods::This retrospective cohort study, conducted at Peking University Third Hospital from August 2011 to December 2020, used data from 375 women aged 20 to 45 years who had dichorionic twin pregnancies that were confirmed through first-trimester ultrasound. After exclusions, reference curves were developed using 318 women with 3,299 DVP scans, and the data analyzed included maternal demographics, pregnancy outcomes, ultrasound measurements, and neonatal information. DVPs were assessed via ultrasound at regular intervals and grouped by gestational age (GA) for analyses. Linear mixed models were used to create amniotic fluid reference curves. Associations between abnormalities and adverse perinatal outcomes were examined using Chi-squared or Fisher's exact tests. Logistic regression provided both crude and adjusted odds ratios, adjusting for pre-pregnancy weight, age, ethnicity, parity, and conception mode. Significance was set at P < 0.05 with 95% confidence intervals (CI), and the analyses were conducted using SPSS ver. 26.0 (IBM Corp., Armonk, NY) and SAS ver. 9.4 (SAS Institute Inc., Cary, NC, USA) software. Results::DVP increased from the first trimester to a maximum at 26 weeks (95% confidence interval ( CI), 2.7-8.3 cm for twin 1 and 2.8-7.9 cm for twin 2) and then decreased gradually toward term. Differences between twins 1 and 2 were significant after 26 weeks (95% CI for twin 1: 5.3, 5.5; 95% CI for twin 2: 4.4, 4.5; P < 0.010). Polyhydramnios of twin 1 increased the risk of large for GA. Oligohydramnios of twin 1 increased the risk of small for GA. Polyhydramnios of twin 2 increased the risk of small for GA, premature birth, and neonatal complications. Oligohydramnios of twin 2 increased the risk of preeclampsia, hypertensive disorder complicating pregnancy, and premature rupture of membranes. Conclusion::Reference curves for twin amniotic fluid volumes vary by GA and differ between twins, with potential implications for pregnancy outcomes.

Objective::To establish the Chinese population's amniotic fluid deepest vertical pocket (DVP) reference curves for dichorionic twin pregnancies and to investigate DVP links with adverse perinatal outcomes.Methods::This retrospective cohort study, conducted at Peking University Third Hospital from August 2011 to December 2020, used data from 375 women aged 20 to 45 years who had dichorionic twin pregnancies that were confirmed through first-trimester ultrasound. After exclusions, reference curves were developed using 318 women with 3,299 DVP scans, and the data analyzed included maternal demographics, pregnancy outcomes, ultrasound measurements, and neonatal information. DVPs were assessed via ultrasound at regular intervals and grouped by gestational age (GA) for analyses. Linear mixed models were used to create amniotic fluid reference curves. Associations between abnormalities and adverse perinatal outcomes were examined using Chi-squared or Fisher's exact tests. Logistic regression provided both crude and adjusted odds ratios, adjusting for pre-pregnancy weight, age, ethnicity, parity, and conception mode. Significance was set at P < 0.05 with 95% confidence intervals (CI), and the analyses were conducted using SPSS ver. 26.0 (IBM Corp., Armonk, NY) and SAS ver. 9.4 (SAS Institute Inc., Cary, NC, USA) software. Results::DVP increased from the first trimester to a maximum at 26 weeks (95% confidence interval ( CI), 2.7-8.3 cm for twin 1 and 2.8-7.9 cm for twin 2) and then decreased gradually toward term. Differences between twins 1 and 2 were significant after 26 weeks (95% CI for twin 1: 5.3, 5.5; 95% CI for twin 2: 4.4, 4.5; P < 0.010). Polyhydramnios of twin 1 increased the risk of large for GA. Oligohydramnios of twin 1 increased the risk of small for GA. Polyhydramnios of twin 2 increased the risk of small for GA, premature birth, and neonatal complications. Oligohydramnios of twin 2 increased the risk of preeclampsia, hypertensive disorder complicating pregnancy, and premature rupture of membranes. Conclusion::Reference curves for twin amniotic fluid volumes vary by GA and differ between twins, with potential implications for pregnancy outcomes.

Objective::To build a reference fetal growth chart for the Chinese population based on fetal ultrasound measurements.Methods::This was a multicenter, population-based retrospective cohort study. Longitudinal ultrasound measurement data were collected from 24 hospitals in 18 provinces of China from 1 st September through 31 st October of 2019. The estimated fetal weight (EFW) was calculated based on head circumference, abdominal circumference, and femur length using Hadlock formula 3. Fetal growth curves were estimated using a two-level linear regression model with cubic splines. All participants were divided into two groups: the northern group ( n = 5829) and the southern group ( n = 3246) based on the geographical division of China and male fetus group ( n = 4775) and female fetus group ( n = 4300) based on fetal gender. The EFW was compared by fetal gender and geographical group. All statistical models were adjusted for maternal sociodemographic characteristics. Results::A total of 9075 participants with 31,700 ultrasound measurement records were included in this study. Male fetuses demonstrated significantly larger EFW compared to female ones starting at 16 weeks of gestation and extending to delivery (global test P < 0.01). The overall geographic difference in EFW was significant (global test P = 0.03), and week-specific comparisons showed that the northern group had a greater EFW starting at 15 weeks of gestation and extending to 29 weeks of gestation, although this difference did not extend to the time of delivery. The Z-score of EFW confirmed that our Chinese fetal growth charts differed from previously published standards. Conclusion::This study provides EFW and ultrasound biometric reference measurements for Chinese fetuses and reveals differences from other fetal growth charts. The chart is worth promoting in more regions of China but should be tested prudently before use.

Objective::To build a reference fetal growth chart for the Chinese population based on fetal ultrasound measurements.Methods::This was a multicenter, population-based retrospective cohort study. Longitudinal ultrasound measurement data were collected from 24 hospitals in 18 provinces of China from 1 st September through 31 st October of 2019. The estimated fetal weight (EFW) was calculated based on head circumference, abdominal circumference, and femur length using Hadlock formula 3. Fetal growth curves were estimated using a two-level linear regression model with cubic splines. All participants were divided into two groups: the northern group ( n = 5829) and the southern group ( n = 3246) based on the geographical division of China and male fetus group ( n = 4775) and female fetus group ( n = 4300) based on fetal gender. The EFW was compared by fetal gender and geographical group. All statistical models were adjusted for maternal sociodemographic characteristics. Results::A total of 9075 participants with 31,700 ultrasound measurement records were included in this study. Male fetuses demonstrated significantly larger EFW compared to female ones starting at 16 weeks of gestation and extending to delivery (global test P < 0.01). The overall geographic difference in EFW was significant (global test P = 0.03), and week-specific comparisons showed that the northern group had a greater EFW starting at 15 weeks of gestation and extending to 29 weeks of gestation, although this difference did not extend to the time of delivery. The Z-score of EFW confirmed that our Chinese fetal growth charts differed from previously published standards. Conclusion::This study provides EFW and ultrasound biometric reference measurements for Chinese fetuses and reveals differences from other fetal growth charts. The chart is worth promoting in more regions of China but should be tested prudently before use.

Under the limitation of cross-sectional studies, more researchers are turning their attention to maternal and child cohort studies. However, some problems do exist in the traditional maternal and child cohort studies, if data is only gathered from the hospitals. The limitation would include the contents of research and the high rate of loss to follow-up. With the integration of different medical traits and the progress in big data, the development of maternal and child related cohorts, with characteristics of dynamic follow-up and data sharing, through combining the information and health service systems of different institutions, seem in urgent need. This paper aims to provide some basic achievements in conducting maternal and child cohorts that can serve the related health problems through full-life cycle, and provide new references on conducting cohort studies, aiming at special population or diseases.