The evaluation of the methods used in the diagnosis of intrauterine growth retardation

Risk factors of stunting among children living in an urban slum of Bangladesh: findings of a prospective cohort study

BACKGROUND

Bangladesh is one of the 20 countries with highest burden of stunting globally. A large portion (around 2.2 million) of the population dwells in the slum areas under severe vulnerable conditions. Children residing in the slums are disproportionately affected with higher burden of undernutrition particularly stunting. In this paper, findings of a prospective cohort study which is part of a larger multi-country study are presented.

METHODS

Two hundred and sixty five children were enrolled and followed since their birth till 24 months of age. Anthropometric measurements, dietary intake and morbidity information were collected monthly. Data from 9 to 12, 15-18 and 21-24 months were collated to analyze and report findings for 12, 18 and 24 months of age. Generalized estimating equation models were constructed to determine risk factors of stunting between 12 and 24 months of age.

RESULT

Approximately, 18% of children were already stunted (LAZ < -2SD) at birth and the proportion increased to 48% at 24 months of age. Exclusive breastfeeding prevalence was only 9.4% following the WHO definition at 6 months. Dietary energy intake as well as intakes of carbohydrate, fat and protein were suboptimal for majority of the children. However, in regression analysis, LAZ at birth (AOR = 0.40, 95% CI: 0.26, 0.61), household with poor asset index (AOR = 2.81, 95% CI: 1.43, 5.52; ref.: average asset index), being male children (AOR = 1.75, 95% CI: 1.04, 2.95; ref.: female) and age (AOR = 2.34, 95% CI: 1.56, 3.52 at 24 months, AOR = 2.13, 95% CI: 1.55, 2.92 at 18 months; ref.: 12 months of age) were the significant predictors of stunting among this population.

CONCLUSION

As the mechanism of stunting begins even before a child is born, strategies must be focused on life course approach and preventive measurement should be initiated during pregnancy. Alongside, government and policymakers have to develop sustainable strategies to improve various social and environmental factors those are closely interrelated with chronic undernutrition particularly concentrating on urban slum areas.

Stunting at birth: recognition of early-life linear growth failure in the western highlands of Guatemala

OBJECTIVE

Measurements of length at birth, or in the neonatal period, are challenging to obtain and often discounted for lack of validity. Hence, classical 'under-5' stunting rates have been derived from surveys on children from 6 to 59 months of age. Guatemala has a high prevalence of stunting (49.8%), but the age of onset of growth failure is not clearly defined. The objective of the study was to assess length-for-age within the first 1.5 months of life among Guatemalan infants.

DESIGN

As part of a cross-sectional observational study, supine length was measured in young infants. Mothers' height was measured. Length-for-age Z-scores (HAZ) were generated and stunting was defined as HAZ <-2 using WHO growth standards.

SETTING

Eight rural, indigenous Mam-Mayan villages (n 200, 100% of Mayan indigenous origin) and an urban clinic of Quetzaltenango (n 106, 27% of Mayan indigenous origin), Guatemala.

SUBJECTS

Three hundred and six newborns with a median age of 19 d.

RESULTS

The median rural HAZ was -1.56 and prevalence of stunting was 38%; the respective urban values were -1.41 and 25%. Linear regression revealed no relationship between infant age and HAZ (r = 0.101, r(2) = 0.010, P = 0.077). Maternal height explained 3% of the variability in HAZ (r = 0.171, r(2) = 0.029, P = 0.003).

CONCLUSIONS

Stunting must be carried over from in utero growth retardation in short-stature Guatemalan mothers. As linear growth failure in this setting begins in utero, its prevention must be linked to maternal care strategies during gestation, or even before. A focus on maternal nutrition and health in an intergenerational dimension is needed to reduce its prevalence.

Symphysis-fundal height curve in the diagnosis of fetal growth deviations

OBJECTIVE

To validate a new symphysis-fundal curve for screening fetal growth deviations and to compare its performance with the standard curve adopted by the Brazilian Ministry of Health.

METHODS

Observational study including a total of 753 low-risk pregnant women with gestational age above 27 weeks between March to October 2006 in the city of João Pessoa, Northeastern Brazil. Symphisys-fundal was measured using a standard technique recommended by the Brazilian Ministry of Health. Estimated fetal weight assessed through ultrasound using the Brazilian fetal weight chart for gestational age was the gold standard. A subsample of 122 women with neonatal weight measurements was taken up to seven days after estimated fetal weight measurements and symphisys-fundal classification was compared with Lubchenco growth reference curve as gold standard. Sensitivity, specificity, positive and negative predictive values were calculated. The McNemar χ2 test was used for comparing sensitivity of both symphisys-fundal curves studied.

RESULTS

The sensitivity of the new curve for detecting small for gestational age fetuses was 51.6% while that of the Brazilian Ministry of Health reference curve was significantly lower (12.5%). In the subsample using neonatal weight as gold standard, the sensitivity of the new reference curve was 85.7% while that of the Brazilian Ministry of Health was 42.9% for detecting small for gestational age.

CONCLUSIONS

The diagnostic performance of the new curve for detecting small for gestational age fetuses was significantly higher than that of the Brazilian Ministry of Health reference curve.

Preventing low birth weight: is prenatal care the answer?

OBJECTIVES

To review the evidence of effectiveness of prenatal care for preventing low birth weight (LBW).

METHODS

We reviewed original research, systematic reviews, meta-analyses and commentaries for evidence of effectiveness of the three core components of prenatal care--risk assessment, health promotion and medical and psychosocial interventions--for preventing the two constituents of LBW: preterm birth and intrauterine growth restriction (IUGR).

RESULTS

Clinical risk assessment will fail to identify the majority of pregnancies at risk for preterm delivery or IUGR. While biophysical and biochemical modalities appear promising, their cost-effectiveness has not been demonstrated, nor can their routine use be recommended in the absence of effective interventions. Smoking cessation programs appear to be modestly effective. There is insufficient evidence to conclude a benefit for nutrition interventions, work counseling or preterm birth education. Only antenatal corticosteroid therapy has demonstrated a clear benefit in the tertiary prevention of preterm delivery. Interventions for which there is insufficient evidence to conclude a benefit include bed rest, hydration, sedation, cerclage, progesterone supplementation, antibiotic treatment, tocolysis without concomitant use of corticosteroids, thyrotropin-releasing hormone, psychosocial support and home visitation. Additionally, there is a paucity of evidence supporting the effectiveness of prenatal interventions, such as low-dose aspirin, bed rest, maternal hyperoxygenation, plasma volume expansion and antenatal fetal assessment, in preventing IUGR or its associated morbidity and mortality.

CONCLUSIONS

Neither preterm birth nor IUGR can be effectively prevented by prenatal care in its present form. Preventing LBW will require reconceptualization of prenatal care as part of a longitudinally and contextually integrated strategy to promote optimal development of women's reproductive health not only during pregnancy, but over the life course.

The predictive value of plasma fibronectin concentration on fetal growth retardation at earlier stage of the third trimester

In order to evaluate the predictive value of maternal plasma fibronectin (FN) concentration at 24-34 weeks on fetal intrauterine growth retardation (IUGR), a prospective double-blinded study was performed. The maternal plasma FN concentrations were measured by using a rate nephelometric procedure in the 130 initial normal nulliparous pregnant woman at 24-34 gestational weeks. The outcome of pregnancies and birth weight of their infants were followed up. IUGR was defined as that the birth weight was less than the 10th percentile for gestational age. The receiver operating characteristic curves and predictive values of FN predicting on outcome of pregnancy with IUGR were analyzed. The results showed that: (1) In a cohort of 130 initially normal nulliparous pregnant women, IUGR occurred in 14 cases during the follow-up; (2) The plasma FN levels in the women with IUGR (467.58 +/- 104.43 mg/L) were significantly higher than in the normal control group (299.44 +/- 105.55 mg/L, P < 0.01). However, there was no significant difference in the mean maternal age, gravidity, sampling gestational ages, delivering gestational ages between the two groups (P > 0.05); (3) The areas under ROC curve for predicting the outcome of pregnancy in IUGR was 0.893; (4) At the cut point of 475 mg/L FN level, the sensitivity, specificity, positive predictive value, negative predictive value and Kappa index for predicting the outcomes of pregnancy in IUGR were 57.14%, 95.69%, 61.54%, 94.87%, 0.5455 respectively. It was concluded that the maternal plasma FN might be used as an earlier predictor for screening of IUGR.

Recent advances in the use of Doppler waveform indices in the antenatal assessment of intrauterine growth retardation

Doppler ultrasound has been advocated as a useful tool to evaluate pregnancies with intrauterine growth retardation (IUGR). However, many previous studies have used smallness for gestational age (SGA) at birth to define IUGR. The ability of Doppler ultrasound to predict SGA, neonatal morphometric indices of wasting such as a low ponderal index, and perinatal morbidity is reviewed. Doppler assessment of the umbilical and uteroplacental vasculatures were inferior to ultrasound measurements of fetal size in the prediction of SGA. In low risk fetuses, umbilical artery waveform indices were of limited value in the prediction of neonatal morphometric indices of wasting. Within a group of high risk fetuses, Doppler assessment of the umbilical artery and, in particular, the middle cerebral and aortic vessels, were useful in predicting fetuses with neonatal wasting. Similar findings were noted in the prediction of perinatal morbidity. The review confirms the usefulness of umbilical artery Doppler waveform indices in the antenatal assessment of IUGR. Whilst preliminary studies appear to suggest that Doppler waveform indices of the middle cerebral and aortic vessels may confer an additional advantage in the antenatal assessment of IUGR, randomized controlled trials evaluating their effect on perinatal outcome and studies on the reproducibility of these indices need to be carried out before their widespread introduction into obstetric practice.

Validity of symphysis fundus growth measurements

OBJECTIVES

Evaluation of symphysis fundus measurements in a large antenatal clinic.

METHODS

The obstetrical records were reviewed for all patients that had delivered over a 3-month period. From this group of 1455, a sample of 386 was taken that had a singleton pregnancy, had booked before 24 weeks' gestation and had attended the antenatal clinic at least twice. The study group comprised 65 patients with less than expected symphysis fundus growth and a control group of 249 in whom growth seemed adequate. The remaining 72 subjects' files were either incomplete or the interobserver variation of the symphysis fundus measurements at the end of pregnancy seemed too high.

RESULTS

Deficient intra-uterine growth, as shown by the symphysis fundus measurements, was significantly associated with both low birthweight (< 2500 g) (odds ratio 3.02) and intra-uterine growth retardation (IUGR) (odds ratio 3.43), but no association was found with perinatal mortality. The sensitivity for detecting IUGR was 42%.

CONCLUSIONS

Symphysis fundus measurements, as made in our antenatal clinic, seem of limited value. We propose that the number of observers be restricted in order to decrease the interobserver variation.

Ultrasonic fetal weight estimation: analysis of inter- and intra-observer variability

Standard ultrasound measurements were performed by two observers in 40 third-trimester fetuses. Observers were blinded to the results of the measurements. Estimated fetal weight (EFW) was calculated using two published formulae. The intra-observer standard deviation for EFW, assessed using one-way analysis of variance, was < 75 g for both observers. The 95% prediction intervals for inter-observer comparisons of EFW, calculated using the limits of agreement method, were -187.3 g to 139.8 g, and -159.9 g to 124.3 g, using the two formulae. The results suggest that measurements of EFW are reproducible. The prediction interval is comparable to the weekly fetal weight increment in normal fetuses.

Antenatal screening and risk factors for intrauterine growth retardation

Antenatal risk factors in combination with symphysis-fundus distance can identify pregnancies with small infants, who can be divided in genetically small, malformed, and malnourished infants. Only the last category benefit from fetal surveillance. Maternal diseases, pregnancy complications (hypertension), and environmental factors (smoking) are connected to malnourished small infants.

Detection of intrauterine growth deviation. A comparison between symphysis-fundus height and ultrasonic measurements

Efficacy of ultrasonography to detect fetal growth retardation is reviewed. Ultrasound dating is held as a prerequisite. Abdominal anthropometry is reported to reflect fetal growth best. Efficacy of symphysis-fundus (SF) height measurements is reviewed similarly. Proposed protocols that include ultrasound and SF height measurements and other maternal characteristics with known prognostic properties are reported. Preferably, both kinds of measurements should be analyzed longitudinally.

Altered fetal growth: antenatal diagnosis by symphysis-fundal height in India and comparison with western charts

Antenatal identification of altered fetal growth is a significant problem in spite of the availability of sophisticated technology. The present study was undertaken to generate symphysis-fundal height curves locally for an Indian population and to assess their value in predicting altered fetal growth. The measurements were found to have a high sensitivity of 80.8% and specificity of 93.5% in detection of small for date babies and a sensitivity and specificity of 72.2% and 95.2%, respectively in detection of fetal macrosomia. The locally generated symphysis-fundal height charts have been compared with the western charts and the differences stressed. It is concluded that symphysis-fundal height curves should be locally generated for best results.

Detection of small for gestational age fetuses by the combination of clinical risk factors and ultrasonography

Clinical risk factors of fetal growth retardation and targeted ultrasound examinations were combined to detect small for gestational age (SGA) fetuses below the 10th percentile weight for age in 1122 unselected singleton pregnancies, in which the true gestational age was confirmed by ultrasonography at 18 weeks. The prevalence of SGA infants was 6.0% in this population. A risk group of 236 (21%) mothers was referred for an ultrasound examination of fetal growth by the midwives of maternity welfare centers on the basis of low symphysis-fundal height or five other major maternal risk factors (pregnancy associated hypertension, loss of weight gain, a previous SGA infant, pre-pregnancy weight below 50 kg, any smoking during pregnancy). The sensitivity and positive predictive value of the clinical part of the study were 83.6 and 23.7%, respectively. Fetal growth was assessed by measuring both biparietal diameter (BPD) and transverse abdominal diameter. In the clinically selected risk group, 83.9% of the SGA fetuses could be detected by this method using a cutoff level of -1 standard deviation (SD). The two-step screening combining clinical and ultrasonographic methods in the detection of SGA fetuses in general population showed a sensitivity of 70.1%, a specificity of 95.5%, a positive predictive value of 49.5%, and a negative predictive value of 98.1%. After ultrasound examination, the definitive risk group for SGA was 8.5% of the total material of 1122.(ABSTRACT TRUNCATED AT 250 WORDS)

Prediction of ovulation

The purpose of this investigation was to evaluate all available ovulatory diagnostics with respect to sensitivity, specificity, diagnostic specificity (predictive value of a positive test, PVP) and diagnostic sensitivity (predictive value of a negative test, PVN). Twenty-one ovulatory women with more than 3 years of infertility problems were included in the study. PVP and PVN were highest for detection of urinary luteinizing hormone (LH) peak at ovulation (PVP = 90%, PVN = 95%) and for serum-estradiol peak 1 day before ovulation (PVP = 83%, PVN = 97%). The predictive values were lower for all other tests. The PVP (54%) and PVN (90%) were rather low for detection of ovulation with vaginal electric impedance. However, all ovulations were predicted when urinary LH peak and vaginal impedance were combined. Two women were stimulated with human chorionic gonadotropin to investigate a possible connection between the LH peak and the preovulatory vaginal electric impedance. No close connection between them could be demonstrated. Basal body temperature should not be used for the prediction of ovulation (PVP = 25%). We suggest that ovulation should primarily be predicted from the identification of the urinary LH peak and that other methods be supplementary.

The effect of maternal bladder volume on fundal height measurements

The effect of maternal bladder volume on fundal height measurements was studied in 200 non-obese Black women between 16 and 42 weeks gestation. Fundal height measurements were obtained by the same examiner immediately before and immediately after each subject voided. Examiners were blinded to fundal height measurements and the amount of urine voided. Prevoid fundal height measurements were significantly larger than postvoid fundal height measurements. The differences between pre- and postvoid fundal height measurements varied from -2.8 to 4.6 cm (mean 0.63 cm, SD 1.26). Postvoid fundal height measurements were smaller than the prevoid measurements in 69.5% of the women, and 34.5% of the differences were greater than 1.0 cm. Women who had voided within 30 min before measurement had significantly smaller differences between pre- and postvoid fundal height measurements (n = 20, mean 0.16, SD 1.22) than women who voided more than 30 min before measurement (n = 179, mean 0.68, SD 1.27). These findings indicate that women should be instructed to void within 30 min before fundal height measurements are obtained.

Symphysis-fundus measurements in Asian and Caucasian women in Bradford

A study was undertaken to assess the need for a separate chart of symphysis-fundus measurements for the large Asian population of Bradford. 129 measurements from 47 pregnant Asian patients were compared with 193 measurements from 87 pregnant Caucasian patients. There was insufficient evidence to support the production of a separate chart for the Asian population.

The validity of screening for small-for-gestational-age and low-weight-for-length infants by Doppler ultrasound

A prospective blind study assessed the efficacy of Doppler examination of the umbilical arteries (pulsatility index) as a screening procedure for predicting small-for-gestational-age and low-weight-for-length (low ponderal index) infants. Birthweight below the 2.3rd and 10th centile and ponderal index below the 3rd and 10th centile were chosen as 'cut-off' levels. Of pregnant women from our university hospital population, 400 were examined at 28 and 34 weeks gestation. The sensitivity of the test was low, ranging from 16.9 to 41.7% for the different indices. The predictive value of a negative screening test also was unsatisfactory, ranging from 79.6% to 97.9%. It is concluded that a single umbilical artery Doppler examination at 28 or 34 weeks does not satisfy the need in obstetrics for a simple and accurate technique to screen for small-for-gestational-age and low-weight-for-length infants in an unselected obstetric population.

Antenatal screening for small-for-gestational-age, using risk factors and measurements of the symphysis-fundus distance--6 years of experience

In a previous prospective study, we outlined a screening programme aiming at detection of a high-risk group for small-for-gestational-age (SGA) pregnancies. The present study evaluates this screening programme in all women delivering at the hospital in 1 year and in all women delivering SGA infants during a 6-year period. When screening for SGA, using symphysis-fundus measurements together with risk factors, the false positive rates were unacceptably high. When only using repeated measurements of the symphysis-fundus distance the results were more acceptable (sensitivity 59%, specificity 97%, positive predictive value 15%). Between 1980 to 1985, 18,604 live singleton infants were born. Altogether 156 infants were assessed as SGA (birthweight for gestational age less than -2 S.D.). Two antenatal records from SGA pregnancies were missing and in 14 pregnancies, antenatal detection of SGA would not have improved the prognosis of the infants (severe congenital malformations or preterm delivery due to maternal diseases). Thus, of 140 SGA pregnancies in focus pathological symphysis-fundus measurements occurred in 63%. It is concluded that by repeated measurements of the symphysis-fundus distance, it is quite possible to form a high-risk group for SGA. In this high-risk group, including less than 4% of the pregnant population, the majority of SGA pregnancies are found.

Poor maternal weight gain between 28 and 32 weeks gestation may predict small-for-gestational-age infants

In a retrospective analysis of 158 women considered to have had normal, low-risk pregnancies, 30 gave birth to infants with a birthweight less than the 10th centile for gestation. These 30 women had a significantly poorer mean increase in weight (0.99 kg) between 28 and 32 weeks gestation than the other 128 women (1.95 kg) who gave birth to infants with birthweights above the 10th centile for gestation. There was no statistically significant difference in booking weight, overall weight gain or other variables associated with low birthweight between the two groups of women which suggests that poor maternal weight gain specifically between 28 and 32 weeks gestation may predict small-for-gestational-age infants.

Intrauterine growth retardation: prediction of perinatal distress by Doppler ultrasound

To investigate the ability of umbilical artery Doppler findings to identify true cases at risk of fetal distress among 51 pregnancies clinically judged to be compromised by intrauterine growth retardation (IUGR) Doppler data were related to pregnancy outcome, which was classified into three groups-group 1, healthy babies with normal placental function (16 fetuses), group 2, fetuses with definite signs of placental failure (30), and group 3, non-classifiable pregnancies (5). Group 2 was subdivided into 2A, placental failure with manifest perinatal distress (19), and 2B, placental failure without perinatal distress (11). All 19 compromised and distressed fetuses (group 2A) had extremely pathological Doppler findings, even several weeks before fetal distress became apparent by cardiotocography. The Doppler findings in the 11 small-for-dates fetuses without perinatal distress (group 2B) were inconsistently normal or slightly pathological. All 16 normal infants (group 1) had normal antenatal Doppler data. The Doppler technique thus allows accurate and early recognition of those fetuses who will become distressed perinatally. It also helps to identify which fetuses clinically suspected of IUGR have an adequate placental circulation.