OBJECTIVES: To determine the diagnostic accuracy (sensitivity and specificity) of ultrasound estimated fetal weight discordance (EFWD) of 20% and 25% using different estimated biometric ultrasound measurements compared with the actual BWD as the reference standard in twin pregnancies.
SEARCH METHODS: The search for this review was performed on 15 March 2019. We searched CENTRAL, MEDLINE (Ovid), Embase (Ovid), seven other databases, conference proceedings, reference lists and contacted experts. There were no language or date restrictions applied to the electronic searches, and no methodological filters to maximize sensitivity.
SELECTION CRITERIA: We selected cohort-type studies with delayed verification that evaluated the accuracy of biometric measurements at ultrasound scanning of twin pregnancies that had been proposed for the diagnosis of estimated BWD, compared to BWD measurements after birth as a reference standard. In addition, we only selected studies that considered twin pregnancies and applied a reference standard for EFWD for the target condition of BWD.
DATA COLLECTION AND ANALYSIS: We screened all titles generated by electronic database searches. Two review authors independently assessed the abstracts of all potentially relevant studies. We assessed the identified full papers for eligibility, and extracted data to create 2 × 2 tables. Two review authors independently performed quality assessment using the QUADAS-2 tool. We excluded studies that did not report data in sufficient detail to construct 2 × 2 tables, and where this information was not available from the primary investigators. We assessed the certainty of the evidence using the GRADE approach.
MAIN RESULTS: We included 39 eligible studies with a median study sample size of 140. In terms of risk of bias, there were many unclear statements regarding patient selection, index test and use of proper reference standard. Twenty-one studies (53%) were of methodological concern due to flow and timing. In terms of applicability, most studies were of low concern. Ultrasound for diagnosis of BWD in twin pregnancies at 20% cut-off Twenty-two studies provided data for a BWD of 20% and the summary estimate of sensitivity was 0.51 (95% CI 0.42 to 0.60), and the summary estimate of specificity was 0.91 (95% CI 0.89 to 0.93) (8005 twin pregnancies; very low-certainty evidence). Ultrasound for diagnosis of BWD in twin pregnancies at 25% cut-off Eighteen studies provided data using a BWD discordance of 25%. The summary estimate of sensitivity was 0.46 (95% CI 0.26 to 0.66), and the summary estimate of specificity was 0.93 (95% CI 0.89 to 0.96) (6471 twin pregnancies; very low-certainty evidence). Subgroup analyses were possible for both BWD of 20% and 25%. The diagnostic accuracy did not differ substantially between estimation by abdominal circumference and femur length but femur length had a trend towards higher sensitivity and specificity. Subgroup analyses were not possible by sex of twins, chorionicity or gestational age due to insufficient data.
AUTHORS' CONCLUSIONS: Very low-certainty evidence suggests that EFWD identified by ultrasound has low sensitivity but good specificity in detecting BWD in twin pregnancies. There is uncertain diagnostic value of EFWD; this review suggests there is insufficient evidence to support this index as the sole measure for clinical decision making to evaluate the prognosis of twins with growth discordance. The diagnostic accuracy of other measures including amniotic fluid index and umbilical artery Doppler resistive indices in combination with ultrasound for clinical intervention requires evaluation. Future well-designed studies could also evaluate the impact of chorionicity, sex and gestational age in the diagnostic accuracy of ultrasound for EFWD.
Method: Consecutive women with uncomplicated singleton pregnancies, attending the Academic Obstetrics and Gynecology Unit of the Teaching Hospital Mahamodara Galle, Sri Lanka, with confirmed dates and establishing spontaneous onset of labor and delivering vaginally between gestational age of 34 - 41 weeks, without any obstetric intervention , during the period September 2013 to February 2014 were studied. The gestational age at spontaneous onset of labor and vaginal delivery and the birth weights of the babies were recorded.
Results: There were 3294 consecutive deliveries during this period, and of them 1602 (48.6%) met the inclusion criteria. Median gestational age at delivery was 275 days (range 238-291 days, IQR 269 to 280 days) and the median birth weight was 3000 g (range1700g - 4350g; IQR 2750-3250g). The 10th, 50th and 90th birth weight centiles of the babies delivered at a gestational age of 275 days were approximately 2570g, 3050g and 3550g respectively.
Conclusions: The median gestational age among women with uncomplicated singleton pregnancies who established spontaneous onset of labor and delivered vaginally, without any obstetric intervention, was approximately five days shorter than the traditionally accepted 280 days. At a gestational age of 275 days, the mean birth weight was approximately 3038g and the 50th centile of the birth weight of the babies delivered was approximately 3050g.
AIMS: (1) To investigate the association between birth weight and anthropometric measurements during adulthood; (2) to study the genetic and environmental influences on body measures including birth weight, weight and height among twins; and (3) to assess the variation in heritability versus environment among two cohorts of twins who lived in different geographical areas.
SUBJECTS AND METHODS: Twins were collected from two twin registers. Data on birth weight, adult weight and height in 430 MZ and 170 DZ twins living in two geographically distinct parts of the world were collected. A genetic analysis was performed using MX software.
RESULTS: Birth weight was associated with weight, height and BMI. Both MZ and DZ twins with low birth weight had shorter height during their adult life (p = 0.001), but only MZ twins with lower birth weight were lighter at adulthood (p = 0.001). Intra-pair differences in birth weight were not associated with differences in adult height (p = 0.366) or weight (p = 0.796). Additive genetic effects accounted for 53% of the variance in weight, 43% in height and 55% in birth weight. The remaining variance was attributed to unique environmental effects (15% for weight, 13% for height and 45% for birth weight and only 16% for BMI). Variability was found to be different in the two cohorts. The best fitting model for birth weight and BMI was additive genetic and non-shared environment and for weight and height was additive genetic, non-shared environment (plus common Environment).
CONCLUSIONS: Data suggests that the association between weight at birth and anthropometric measures in later life is influenced by both genetic and environmental factors. Living in different environments can potentially relate to variation found in the environment.
METHODS: This was a comparative cross-sectional study. We recruited children aged 8-11 years from eight primary schools in Kota Bharu, Kelantan, Malaysia. The children were divided into two groups: those with LBW (< 2,500 g) and those with normal birth weight (≥ 2,500 g). Parents of the enrolled children were asked to complete a translated version of the International Study of Asthma and Allergies in Childhood questionnaire. Lung function tests, done using a MicroLoop Spirometer, were performed for the children in both groups by a single investigator who was blinded to the children's birth weight.
RESULTS: The prevalence of 'ever wheezed' among the children with LBW was 12.9%. This value was significantly higher than that of the children with normal birth weight (7.8%). Forced vital capacity (FVC), forced expiratory volume in one second, and forced expiratory flow when 50% and 75% of the FVC had been exhaled were significantly lower among the children with LBW as compared to the children with normal birth weight.
CONCLUSION: LBW is associated with an increased prevalence of asthma-like symptoms and impaired lung function indices later in life. Children born with LBW may need additional follow-up so that future respiratory problems can be detected early.
METHODS: This prospective cross-sectional study aimed to identify rural-urban differences in risk factors for low birth weight among women in Malaysia. Pregnant women at ≥20 weeks of gestation in urban and rural Malaysia (n = 437) completed questionnaires on sociodemographic characteristics and physical activity. Weight and middle-upper arm circumference were measured. Infant birth outcomes were extracted from medical records.
RESULTS: The overall prevalence of low birth weight infants was 6.38%. Rural women had more low birth weight infants than urban women (9.8% vs 2.0%, p = 0.03). Findings showed rural women were less sedentary (p = 0.003) and participated in more household/caregiving activities (p = 0.036), sports activities (p = 0.01) and less occupational activity (p birth weight infants in rural, but not in urban women.
CONCLUSIONS: We observed differences in risk factors for low birth weight between urban and rural pregnant women. Age, malnutrition and low parity were risk factors for low birth weight among rural pregnant women. Our findings suggest that rural pregnant women with low nutritional status should be encouraged to monitor their middle-upper arm circumference consistently throughout pregnancy. Improving nutritional status in rural pregnant women may reduce the risk of low birth weight infants in this population.