Prediction of small-for-gestational-age status by symphysis-fundus height: a registry-based population cohort study

Development and Validation of a Small for Gestational Age Screening Model at 21-24 Weeks Based on the Real-World Clinical Data

BACKGROUND

Small for gestational age (SGA) is a condition in which fetal birthweight is below the 10th percentile for the gestational age, which increases the risk of perinatal morbidity and mortality. Therefore, early screening for each pregnant woman is of great interest. We aimed to develop an accurate and widely applicable screening model for SGA at 21-24 gestational weeks of singleton pregnancies.

METHODS

This retrospective observational study included medical records of 23,783 pregnant women who gave birth to singleton infants at a tertiary hospital in Shanghai between 1 January 2018 and 31 December 2019. The obtained data were nonrandomly classified into training (1 January 2018 to 31 December 2018) and validation (1 January 2019 to 31 December 2019) datasets based on the year of data collection. The study variables, including maternal characteristics, laboratory test results, and sonographic parameters at 21-24 weeks of gestation were compared between the two groups. Further, univariate and multivariate logistic regression analyses were performed to identify independent risk factors for SGA. The reduced model was presented as a nomogram. The performance of the nomogram was assessed in terms of its discrimination, calibration, and clinical usefulness. Moreover, its performance was assessed in the preterm subgroup of SGA.

RESULTS

Overall, 11,746 and 12,037 cases were included in the training and validation datasets, respectively. The developed SGA nomogram, comprising 12 selected variables, including age, gravidity, parity, body mass index, gestational age, single umbilical artery, abdominal circumference, humerus length, abdominal anteroposterior trunk diameter, umbilical artery systolic/diastolic ratio, transverse trunk diameter, and fasting plasma glucose, was significantly associated with SGA. The area under the curve value of our SGA nomogram model was 0.7, indicating a good identification ability and favorable calibration. Regarding preterm SGA fetuses, the nomogram achieved a satisfactory performance, with an average prediction rate of 86.3%.

CONCLUSIONS

Our model is a reliable screening tool for SGA at 21-24 gestational weeks, especially for high-risk preterm fetuses. We believe that it will help clinical healthcare staff to arrange more comprehensive prenatal care examinations and, consequently, provide a timely diagnosis, intervention, and delivery.

Dynamic prediction model of fetal growth restriction based on support vector machine and logistic regression algorithm

Background

This study analyzed the influencing factors of fetal growth restriction (FGR), and selected epidemiological and fetal parameters as risk factors for FGR.

Objective

To establish a dynamic prediction model of FGR.

Methods

This study used two methods, support vector machine (SVM) and multivariate logistic regression, to establish the prediction model of FGR at different gestational weeks.

Results

At 20–24 weeks and 25–29 weeks of gestation, the effect of the multivariate Logistic method on model prediction was better. At 30–34 weeks of gestation, the prediction effect of FGR model using the SVM method is better. The ROC curve area was above 85%.

Conclusions

The dynamic prediction model of FGR based on SVM and logistic regression is helpful to improve the sensitivity of FGR in pregnant women during prenatal screening. The establishment of prediction models at different gestational ages can effectively predict whether the fetus has FGR, and significantly improve the clinical treatment effect.

Routinely collected antenatal data for longitudinal prediction of preeclampsia in nulliparous women: a population-based study

The objective was to evaluate the sequentially updated predictive capacity for preeclampsia during pregnancy, using multivariable longitudinal models including data from antenatal care. This population-based cohort study in the Stockholm-Gotland Counties, Sweden, included 58,899 pregnancies of nulliparous women 2008-2013. Prospectively collected data from each antenatal care visit was used, including maternal characteristics, reproductive and medical history, and repeated measurements of blood pressure, weight, symphysis-fundal height, proteinuria, hemoglobin and blood glucose levels. We used a shared-effects joint longitudinal model including all available information up until a given gestational length (week 24, 28, 32, 34 and 36), to update preeclampsia prediction sequentially. Outcome measures were prediction of preeclampsia, preeclampsia with delivery < 37, and preeclampsia with delivery ≥ 37 weeks' gestation. The area under the curve (AUC) increased with gestational length. AUC for preeclampsia with delivery < 37 weeks' gestation was 0.73 (95% CI 0.68-0.79) at week 24, and increased to 0.87 (95% CI 0.84-0.90) in week 34. For preeclampsia with delivery ≥ 37 weeks' gestation, the AUC in week 24 was 0.65 (95% CI 0.63-0.68), but increased to 0.79 (95% CI 0.78-0.80) in week 36. The addition of routinely collected clinical measurements throughout pregnancy improve preeclampsia prediction and may be useful to individualize antenatal care.

INTERGROWTH-21 Identifies High Prevalence of Low Symphysis-Fundal Height in Indigenous Pregnant Women Experiencing Multiple Infections, Nutrient Deficiencies, and Inflammation: The Maternal Infections, Nutrient Deficiencies, and Inflammation (MINDI) Cohort

BACKGROUND

In the absence of ultrasound, symphysis-fundal height (SFH) can assess maternal-fetal well-being as it is associated with gestational age, fetal weight, and amniotic fluid volume. However, other modifiers of SFH, including maternal infections, nutrient deficiencies, and inflammation (MINDI), have not been widely explored.

OBJECTIVES

Our objectives were 2-fold: 1) to assess prevalence of low SFH in indigenous Panamanian women using both Pan-American Health Organization (PAHO) and INTERGROWTH-21 standards and 2) to explore associations of SFH with maternal health indicators: infections (oral, skin, urogenital, nematode infections), nutrient deficiencies [protein and iron indicators (ferritin, serum iron, serum transferrin receptor, hepcidin), folate, and vitamins A, D, and B-12], and inflammation [leukocytes, C-reactive protein (CRP), cytokines].

METHODS

For this cross-sectional study, low-SFH-for-gestational-age was assessed using PAHO and INTERGROWTH <10th centile in 174 women at ≥16 weeks of gestation. Bootstrapping selected MINDI variables for inclusion in multivariable fractional polynomial (MFP) logistic regressions for low SFH. Associations of MINDI variables with hepcidin were also investigated.

RESULTS

Prevalence of low SFH was 8% using PAHO, but using INTERGROWTH, 50.6% had SFH <10th centile, including 37.9% <3rd centile. Both PAHO-SFH <10th centile and INTERGROWTH-SFH <3rd centile were associated with higher hepcidin (OR = 1.12, P = 0.008, and OR = 3.04, P = 0.001, respectively) and with lower TNF-α (OR = 0.73, P = 0.012, and OR = 0.93, P = 0.015, respectively). Wood-smoke exposure increased the odds of PAHO-SFH <10th centile (OR = 1.19, P = 0.009), whereas higher BMI decreased the odds of INTERGROWTH-SFH <3rd centile (OR = 0.87, P = 0.012). Lower pulse pressure (OR = 0.90, P = 0.009) and lower inflammatory responses [lower lymphocytes (OR = 0.21, P = 0.026), IL-17 (OR = 0.89, P = 0.011)] distinguished SFH <3rd centile from SFH ≥3rd to <10th centiles using INTERGROWTH-21 standards. The MFP regression for hepcidin controlling for SFH (adjusted R 2 = 0.40, P = 0.001) revealed associations with indicators of inflammation (CRP, P < 0.0001; IL-17, P = 0.012), acidic urinary pH (P = 0.008), and higher intake of supplements (P = 0.035).

CONCLUSIONS

Associations of low SFH with MINDI variables, including hepcidin, highlight its potential for early detection of multicausal in utero growth faltering.

Fetal Growth Restriction Prediction: How to Move beyond

The actual burden and future burden of the small-for-gestational-age (SGA) babies turn their screening in pregnancy a question of major concern for clinicians and policymakers. Half of stillbirths are due to growth restriction in utero, and possibly, a quarter of livebirths of low- and middle-income countries are SGA. Growing body of evidence shows their higher risk of adverse outcomes at any period of life, including increased rates of neurologic delay, noncommunicable chronic diseases (central obesity and metabolic syndrome), and mortality. Although there is no consensus regarding its definition, birthweight centile threshold, or follow-up, we believe birthweight <10th centile is the most suitable cutoff for clinical and epidemiological purposes. Maternal clinical factors have modest predictive accuracy; being born SGA appears to be of transgenerational heredity. Addition of ultrasound parameters improves prediction models, especially using estimated fetal weight and abdominal circumference in the 3rd trimester of pregnancy. Placental growth factor levels are decreased in SGA pregnancies, and it is the most promising biomarker in differentiating angiogenesis-related SGA from other causes. Unfortunately, however, only few societies recommend universal screening. SGA evaluation is the first step of a multidimensional approach, which includes adequate management and long-term follow-up of these newborns. Apart from only meliorating perinatal outcomes, we hypothesize SGA screening is a key for socioeconomic progress.

Examining the predictive accuracy of metabolomics for small-for-gestational-age babies: a systematic review

INTRODUCTION

To date, there is no robust enough test to predict small-for-gestational-age (SGA) infants, who are at increased lifelong risk of morbidity and mortality.

OBJECTIVE

To determine the accuracy of metabolomics in predicting SGA babies and elucidate which metabolites are predictive of this condition.

DATA SOURCES

Two independent researchers explored 11 electronic databases and grey literature in February 2018 and November 2018, covering publications from 1998 to 2018. Both researchers performed data extraction and quality assessment independently. A third researcher resolved discrepancies.

STUDY ELIGIBILITY CRITERIA

Cohort or nested case-control studies were included which investigated pregnant women and performed metabolomics analysis to evaluate SGA infants. The primary outcome was birth weight <10th centile-as a surrogate for fetal growth restriction-by population-based or customised charts.

STUDY APPRAISAL AND SYNTHESIS METHODS

Two independent researchers extracted data on study design, obstetric variables and sampling, metabolomics technique, chemical class of metabolites, and prediction accuracy measures. Authors were contacted to provide additional data when necessary.

RESULTS

A total of 9181 references were retrieved. Of these, 273 were duplicate, 8760 were removed by title or abstract, and 133 were excluded by full-text content. Thus, 15 studies were included. Only two studies used the fifth centile as a cut-off, and most reports sampled second-trimester pregnant women. Liquid chromatography coupled to mass spectrometry was the most common metabolomics approach. Untargeted studies in the second trimester provided the largest number of predictive metabolites, using maternal blood or hair. Fatty acids, phosphosphingolipids and amino acids were the most prevalent predictive chemical subclasses.

CONCLUSIONS AND IMPLICATIONS

Significant heterogeneity of participant characteristics and methods employed among studies precluded a meta-analysis. Compounds related to lipid metabolism should be validated up to the second trimester in different settings.

PROSPERO REGISTRATION NUMBER

CRD42018089985.

Fetal abdominal circumference in the second trimester and prediction of small for gestational age at birth

Background: Infants that are small for gestational age (SGA) at birth are at increased risk for morbidity and mortality. Unfortunately, the antenatal prediction of SGA is suboptimal.Objectives: We sought to: (1) examine the association between second trimester fetal abdominal circumference < 10% (2T-AClag) with SGA and other gestational and neonatal adverse outcomes; (2) assess 2T-AClag as a predictor of SGA.Study design: Retrospective study of 212 singleton gestations with 2T-AClag on routine ultrasound between 18-24 weeks. The study group was compared to 424 gestations without 2T-AClag for maternal characteristics as well as pregnancy and neonatal adverse outcomes. A multivariate logistic regression was used to determine the predictive value of 2T-AClag for SGA, adjusting for maternal and pregnancy characteristics. The screening model accuracy was assessed through receiver operating characteristic (ROC) curves. Fetal growth restriction (FGR) was defined as an estimated fetal weight (EFW) less than the 10th percentile.Results: Gestations with 2T-AClag had higher rates of SGA (35.7 versus 11.6%, p  <  .0001), FGR (17 versus 1.7%, p < .0001), pregnancy induced hypertension (31.1 versus 17%, p < .0001), preeclampsia (14.6 versus 7.8%, 0  =  0.01), abnormal umbilical artery Doppler (30 versus 5.1%, p < .0001), indicated preterm birth (5.7 versus 1.9%, p = .01), primary cesarean birth (29.6 versus 20.1%, p = .01) and NICU admission (12.9 versus 6.4%, p = .009). After adjusting for maternal and gestational risk factors, 2T-AClag remained an independent risk factor for SGA (OR 4.53, 95%CI 2.91-7.05, p < .0001) and FGR (OR 11.57, 95%CI 5.02-26.65, p < .0001). The inclusion of 2T-AClag in a regression model with traditional risk factors, significantly improved the model's predictability for SGA and FGR (area under ROC curve increased from 0.618 to 0.723 and 0.653 to 0.819, respectively, p < .0001).Conclusions: Second trimester abdominal circumference (AC) lag is associated with an increased risk of SGA, FGR and other adverse outcomes. The inclusion of 2T-AClag in a screening model for prediction of SGA and FGR may improve the identification of this at-risk group and assist in customizing surveillance plans.Brief rationaleScreening for newborns that are small for gestational age (SGA) at birth is currently suboptimal. Our study shows that second trimester abdominal circumference (AC) lag, using a parameter already routinely assessed during anatomic survey, is associated with SGA at birth and can improve current screening for growth restriction and other gestational, fetal and neonatal complications.

Small-for-gestational-age babies of low-risk term pregnancies: does antenatal detection matter?

OBJECTIVES

To compare delivery route and admission rate to neonatal intensive care unit between small- and appropriate-for-gestational-age babies among low-risk term pregnancies.

METHODS

A retrospective study was conducted using the database of deliveries in 2014 at a tertiary hospital. Babies delivered at ≥37 weeks with birthweight <10th centile were considered small-for-gestational-age (SGA) and >90th centile were considered large-for-gestational-age. Fetal weight estimation at 30-33 weeks ultrasound <10th centile was considered antenatal detection of SGA.

RESULTS

Among 1429 low-risk term pregnancies, 11% (151/1429) had SGA babies and 5% (75/1429) had large-for-gestational-age. SGA babies were associated with higher rate of cesarean sections for nonreassuring fetal status (18/151 versus 8/1202, p < .001) and higher rate of admissions to neonatal intensive care unit (16/151 versus 18/1202, p < .001) compared to appropriate-for-gestational-age. Within SGA group, antepartum detected fetuses were associated with lower rate of operative deliveries for nonreassuring fetal status than undetected group (3/31 versus 39/120, p = .01) Conclusions: In our series, women with SGA term babies were associated with more adverse obstetric and neonatal outcome than appropriate-for-gestational age, especially among those undetected prenatally.