Fetal growth velocity references from a Chinese population-based fetal growth study

Specific growth velocity reference charts for monochorionic twin pregnancies

OBJECTIVE

We aimed to create specific growth velocity reference charts for monochorionic (MC) twin pregnancies and provide additional information for assessing fetal growth in MC twins.

STUDY DESIGN

This retrospective study collected data from uncomplicated MC twins with serial ultrasound parameters. The four ultrasound parameters, including biparietal diameter, femur length, head circumference, and abdominal circumference, were used to calculate the estimated fetal weight (EFW). Multilevel linear regression models were applied to fit growth velocity charts for each biometric parameter and EFW. Analysis of variance was used to examine differences in birthweight by whether EFW velocity and EFW values were <10th or ≥10th percentiles.

RESULTS

The final analysis encompassed a total of 5956 ultrasound examinations conducted on 487 MC twins. The growth velocity of four biparietal diameters exhibited a gradual decrease in a nearly linear fashion progressing from 18 to 37 gestational weeks. The EFW velocity increased steadily from 18 to 36 gestational weeks, reaching a peak of 178.2 g/week, and then the velocity gradually decreased until delivery. At 32 weeks for illustration, the lightest birth weight was observed when both EFW and EFW velocity were <10th percentile (1899 g). The study also found that birth weight was higher when EFW velocity was ≥10th percentile compared with <10th percentile, regardless of EFW being below or above the 10th percentile (2263 and 1906 g, respectively; P < 0.001).

CONCLUSION

We developed specific growth velocity reference charts for MC twins, which could provide a valuable reference point for a more precise evaluation of fetal growth in MC twins. Preliminary findings indicate that the inclusion of fetal growth velocity in monitoring fetal growth provides additional information beyond EFW alone.

Prediction by uterine artery Doppler screening of small-for-gestational-age neonates at 19-24 weeks' gestation

OBJECTIVE

Small-for-gestational-age (SGA) neonates are at increased risk of perinatal mortality and morbidity. We aimed to investigate the performance of uterine artery pulsatility index (UtA-PI) at 19-24 weeks' gestation to predict the delivery of a SGA neonate in a Chinese population.

METHODS

This was a retrospective cohort study using data obtained between January 2010 and June 2018. Doppler ultrasonography was performed at 19-24 weeks' gestation. SGA was defined as birth weight below the 10th centile according to the INTERGROWTH-21st fetal growth standards. The performance of UtA-PI to predict the delivery of a SGA neonate was assessed using receiver-operating-characteristics (ROC)-curve analysis.

RESULTS

We included 6964 singleton pregnancies, of which 748 (11%) delivered a SGA neonate, including 115 (15%) women with preterm delivery. Increased UtA-PI was associated with an elevated risk of SGA, both in neonates delivered at or after 37 weeks' gestation (term SGA) and those delivered before 37 weeks (preterm SGA). The areas under the ROC curve (AUCs) for UtA-PI were 64.4% (95% CI, 61.5-67.3%) and 75.8% (95% CI, 69.3-82.3%) for term and preterm SGA, respectively. The performance of combined screening by maternal demographic/clinical characteristics and estimated fetal weight in the detection of term and preterm SGA was improved significantly by the addition of UtA-PI, although the increase in AUC was modest (2.4% for term SGA and 4.9% for preterm SGA).

CONCLUSIONS

This is the first Chinese study to evaluate the role of UtA-PI at 19-24 weeks' gestation in the prediction of the delivery of a neonate with SGA. The addition of UtA-PI to traditional risk factors improved the screening performance for SGA, and this improvement was greater in predicting preterm SGA compared with term SGA. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Maternal Prenatal Depressive Symptoms and Fetal Growth During the Critical Rapid Growth Stage

Importance

Fetal growth in the critical rapid growth stage (CRGS) before delivery, approximately between 30 to 37 gestational weeks, carries significant implications for subsequent overweight, obesity, and arterial health. Previous evidence has demonstrated the association between maternal depressive symptoms and fetal growth trajectories from early to late pregnancy, but there remains limited understanding of the association of these symptoms with the longitudinal fetal growth change within the CRGS.

Objective

To investigate the association between maternal depressive symptoms and fetal growth during the CRGS before delivery.

Design, Setting, and Participants

This prospective birth cohort study was conducted from January 2018 to December 2020. Volunteer pregnant women were enrolled in their first trimester of prenatal visits. Women with severe disease before pregnancy and multiple births, fetuses with congenital anomalies, and preterm or postterm births were excluded. This multicenter study was based in 13 hospitals covering 81 counties across 12 cities in Sichuan Province, China. Follow-up visits were performed at the second trimester, the third trimester, and 24 hours after delivery. The analysis was conducted from January to May 2023.

Exposures

Maternal depressive symptoms, as a continuous variable, measured by the Edinburgh Postpartum Depression Scale (EPDS) at a median gestational week of 24 (range, 14 to 27) weeks of gestation. A higher score on the EPDS indicates worse depressive symptoms.

Main Outcomes and Measures

The main outcomes included ultrasonography-measured biparietal diameter (BPD), femur length (FL), and abdominal circumference (AC), along with calculated estimated fetal weight (EFW). These parameters were evaluated longitudinally at a median gestational week of 30 (range, 28 to 32) and 37 (range, 35 to 39) weeks. Linear mixed models were used to estimate the associations between maternal depressive symptoms and fetal growth parameters.

Results

A total of 2676 mother-offspring dyads were included, in which the mean (SD) age of mothers was 28.0 (4.4) years, and 1294 (48.4%) of the offspring were female. The median (IQR) maternal EPDS score was 5.0 (4.0 to 9.0). After adjustment for confounders, a significant correlation was found between a higher score of depressive symptoms in mothers and a slower rate of fetal growth across FL (β = -0.40; 95% CI, -0.58 to -0.22), AC (β = -1.97; 95% CI, -2.90 to -1.03), and EFW (β = -50.11; 95% CI, -68.46 to -31.75). These associations were stronger in female fetuses or those with better family socioeconomic conditions.

Conclusions and Relevance

In this prospective cohort study, maternal depressive symptoms were associated with slower fetal growth rate in the CRGS before delivery. Early screening for depressive disorders in pregnant women appears to be essential for fetal growth and later health.

Trimester-specific reference intervals for hemoglobin A1c in non-diabetic pregnancy in a Chinese population

BACKGROUND

Physiological glycated hemoglobin (HbA1c) values in each trimester are not well defined. This study aimed to determine trimester-specific reference intervals for HbA1c levels in non-diabetic pregnant women in China.

METHODS

In this cross-sectional study, 5,042 Chinese pregnant women from 6 to 41 weeks of gestation were screened. An inclusion of 4,134 non-diabetic women was made to determine the reference intervals, they were divided into three trimesters: trimester 1 (T1), 6 weeks to 13 weeks + 6 days, trimester 2 (T2), 14 weeks to 27 weeks + 6 days, and trimester 3 (T3), 28 weeks to 41 weeks + 6 days. A total of 4,134 women (T1 n = 760, T2 n = 1,953, and T3 n = 1,421) provided blood samples which were analyzed for HbA1c concentrations. HbA1c was measured using high-performance liquid chromatography. The median and percentile (2.5th to 97.5th) for the HbA1c reference intervals were calculated for each trimester.

RESULTS

In total, 8,732 HbA1c measurements were taken. Reference intervals for HbA1c expressed as median and percentile (2.5th to 97.5th) for each trimester were: T1: 4.7 (4.0-5.5%), T2: 4.5 (3.9-5.3%), and T3: 4.8 (4.1-5.7%) respectively. The HbA1c levels were significantly lower in the second trimester compared to those in the first trimester (p < 0.0001), and higher in the third trimester compared to the second trimester (p < 0.0001).

CONCLUSIONS

The reference intervals for HbA1c levels were 3.9-5.7% with upper limits of 5.5% in the first trimester, 5.3% in the second trimester, and 5.7% in the third trimester. These findings highlight the importance of considering trimester-specific reference intervals for HbA1c in non-diabetic pregnant women to promote maternal and fetal health.