Detection of small-for-gestational-age fetuses by ultrasound screening in a high risk population: a randomized controlled study

Routine ultrasound for fetal assessment before 24 weeks' gestation

BACKGROUND

Ultrasound examination of pregnancy before 24 weeks gestation may lead to more accurate dating and earlier diagnosis of pathology, but may also give false reassurance. It can be used to monitor development or diagnose conditions of an unborn baby. This review compares the effect of routine or universal, ultrasound examination, performed before 24 completed weeks' gestation, with selective or no ultrasound examination.  OBJECTIVES: To assess the effect of routine pregnancy ultrasound before 24 weeks as part of a screening programme, compared to selective ultrasound or no ultrasound, on the early diagnosis of abnormal pregnancy location, termination for fetal congenital abnormality, multiple pregnancy, maternal outcomes and later fetal compromise. To assess the effect of first trimester (before 14 weeks) and second trimester (14 to 24 weeks) ultrasound, separately.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, and the World Health Organization's International Clinical Trials Registry Platform (ICTRP) on 11 August 2020. We also examined the reference lists of retrieved studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs), quasi-RCTs, cluster-RCTs and RCTs published in abstract form. We included all trials with pregnant women who had routine or revealed ultrasound versus selective ultrasound, no ultrasound, or concealed ultrasound, before 24 weeks' gestation. All eligible studies were screened for scientific integrity and trustworthiness.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for eligibility and risk of bias, extracted data and checked extracted data for accuracy. Two review authors independently used the GRADE approach to assess the certainty of evidence for each outcome MAIN RESULTS: Our review included data from 13 RCTs including 85,265 women. The review included four comparisons. Four trials were assessed to be at low risk of bias for both sequence generation and allocation concealment and two as high risk. The nature of the intervention made it impossible to blind women and staff providing care to treatment allocation.  Sample attrition was low in the majority of trials and outcome data were available for most women. Many trials were conducted before it was customary for trials to be registered and protocols published. First trimester routine versus selective ultrasound: four studies, 1791 women, from Australia, Canada, the United Kingdom (UK) and the United States (US). First trimester scans probably reduce short-term maternal anxiety about pregnancy (risk ratio (RR) 0.80, 95% confidence interval (CI) 0.65 to 0.99; moderate-certainty evidence). We do not have information on whether the reduction was sustained.  The evidence is very uncertain about the effect of first trimester scans on perinatal loss (RR 0.97, 95% CI 0.55 to 1.73; 648 participants; one study; low-certainty evidence) or induction of labour for post-maturity (RR 0.83, 95% CI 0.50 to 1.37; 1474 participants; three studies; low-certainty evidence). The effect of routine first trimester ultrasound on birth before 34 weeks or termination of pregnancy for fetal abnormality was not reported. Second trimester routine versus selective ultrasound: seven studies, 36,053 women, from Finland, Norway, South Africa, Sweden and the US. Second trimester scans probably make little difference to perinatal loss (RR 0.98, 95% CI 0.81 to 1.20; 17,918 participants, three studies; moderate-certainty evidence) or intrauterine fetal death (RR 0.97, 95% CI 0.66 to 1.42; 29,584 participants, three studies; low-certainty evidence). Second trimester scans may reduce induction of labour for post-maturity (RR 0.48, 95% CI 0.31 to 0.73; 24,174 participants, six studies; low-certainty evidence), presumably by more accurate dating. Routine second trimester ultrasound may improve detection of multiple pregnancy (RR 0.05, 95% CI 0.02 to 0.16; 274 participants, five studies; low-certainty evidence). Routine second trimester ultrasound may increase detection of major fetal abnormality before 24 weeks (RR 3.45, 95% CI 1.67 to 7.12; 387 participants, two studies; low-certainty evidence) and probably increases the number of women terminating pregnancy for major anomaly (RR 2.36, 95% CI 1.13 to 4.93; 26,893 participants, four studies; moderate-certainty evidence). Long-term follow-up of children exposed to scans before birth did not indicate harm to children's physical or intellectual development (RR 0.77, 95% CI 0.44 to 1.34; 603 participants, one study; low-certainty evidence). The effect of routine second trimester ultrasound on birth before 34 weeks or maternal anxiety was not reported. Standard care plus two ultrasounds and referral for complications versus standard care: one cluster-RCT, 47,431 women, from Democratic Republic of Congo, Guatemala, Kenya, Pakistan and Zambia. This trial included a co-intervention, training of healthcare workers and referral for complications and was, therefore, assessed separately. Standard pregnancy care plus two scans, and training and referral for complications, versus standard care probably makes little difference to whether women with complications give birth in a risk appropriate setting with facilities for caesarean section (RR 1.03, 95% CI 0.89 to 1.19; 11,680 participants; moderate-certainty evidence).  The intervention also probably makes little to no difference to low birthweight (< 2500 g) (RR 1.01, 95% CI 0.90 to 1.13; 47,312 participants; moderate-certainty evidence). The evidence is very uncertain about whether the community intervention (including ultrasound) makes any difference to maternal mortality (RR 0.92, 95% CI 0.55 to 1.55; 46,768 participants; low-certainty evidence). Revealed ultrasound results (communicated to both patient and doctor) versus concealed ultrasound results (blinded to both patient and doctor at any time before 24 weeks): one study, 1095 women, from the UK. The evidence was very uncertain for all results relating to revealed versus concealed ultrasound scan (very low-certainty evidence).

AUTHORS' CONCLUSIONS

Early scans probably reduce short term maternal anxiety.  Later scans may reduce labour induction for post-maturity. They may improve detection of major fetal abnormalities and increase the number of women who choose termination of pregnancy for this reason. They may also reduce the number of undetected twin pregnancies. All these findings accord with observational data.  Neither type of scan appears to alter other important maternal or fetal outcomes, but our review may underestimate the effect in modern practice because trials were mostly  from relatively early in the development of the technology, and many control participants also had scans. The trials were also underpowered to show an effect on other important maternal or fetal outcomes.

Midtrimester Ultrasound Predictors of Small-for-Gestational-Age Neonates

OBJECTIVES

To determine whether a specific estimated fetal weight (EFW) or abdominal circumference (AC) measurement percentile at the 18-to 24-week ultrasound (US) examination is associated with a small-for-gestational-age (SGA) neonate.

METHODS

A retrospective case-control study was conducted including women with uncomplicated singleton gestations who delivered a term SGA neonate identified as having a birth weight (BW) below the 10th percentile on the Olsen growth curve and had an 18- to 24-week US examination in our database. The study period was October 2011 to January 2018. A similar number of control charts were requested randomly over the same time with BW in the 10th to 90th percentiles, all which had an 18-to 24-week US examination in our database. After all neonates meeting BW criteria were identified, a chart review was performed to specifically evaluate biometric parameters from the US at 18 to 24 weeks to determine a potential correlation with the EFW percentile and AC percentile. Pregnancy, neonatal outcomes, and maternal demographic characteristics were collected.

RESULTS

A total of 549 term neonates with a BW below the 10th percentile, and 593 control term neonates with BW in the of 10th to 90th percentiles were reviewed. Our analyses revealed that the AC and EFW percentiles were poor predictors of BW (<10th percentile; areas under the receiver operating characteristic curves, 0.68 and 0.69, respectively). A similar low ability of AC and EFW to predict BW below the 5th percentile was noted.

CONCLUSIONS

(1) No tipping point or cutoff for the EFW or AC percentile at the 18- to 24-week US examination was identified to predict a term SGA neonate. (2) These data are helpful when counseling women in midgestation about specific parameters, their importance, and the potential need for follow up imaging.

Effect of antenatal detection of small-for-gestational-age newborns in a risk stratified retrospective cohort

OBJECTIVE

Small-for-gestational-age (SGA) are neonates born with birth weight below the 10th centile for a given week of pregnancy. It is a risk factor of perinatal and neonatal morbidity and mortality. There is an ongoing debate whether prenatal detection of SGA neonates is good predictor of perinatal outcome especially in low risk populations. Our primary aim was to compare the odds ratios for unfavorable outcome in a risk stratified cohort of SGA neonates in regard to prenatal detection status.

METHODS

This is a retrospective cohort study analysing the effect of prenatal detection on perinatal outcome. This cohort has been divided into a predefined low-risk and high-risk population. Electronic records of 39,032 singleton deliveries from 2010 through 2016 were analysed. SGA was defined as newborn weight below the 10th percentile on the Fenton growth chart. Detected SGA (dSGA) neonates were those that were admitted for delivery with a prenatal ultrasound diagnosis of abnormal growth. Undetected SGA (uSGA) were neonates that were found to be below the 10th percentile after birth. Perinatal and neonatal outcome was compared.

RESULTS

The detection rate in high-risk pregnancies was almost 45.7% versus low risk where it amounted to 18.9%. In both the high-risk and low-risk populations there was a significantly higher risk of composite mortality for undetected SGA compared to approporiate-for-gestational-age (AGA) (OR 7.95 CI 4.76-13.29; OR 14.4 CI 4.99-41.45 respectively). The odds for the composite neonatal outcome were significantly higher for dSGA and uSGA than for AGA in all the studied populations except for the uSGA in high risk population (OR 1.57 CI 0.97-3.53). Importantly, there was not a single case of intrauterine fetal death among detected SGA, in the low risk group.

CONCLUSIONS

Prenatal detection of SGA status is related to perinatal outcomes, especially mortality. Therefore, assessment of SGA status even in low-risk pregnancies could help predict potential perinatal and neonatal complications.

Biochemical tests of placental function versus ultrasound assessment of fetal size for stillbirth and small-for-gestational-age infants

BACKGROUND

Stillbirth affects 2.6 million pregnancies worldwide each year. Whilst the majority of cases occur in low- and middle-income countries, stillbirth remains an important clinical issue for high-income countries (HICs) - with both the UK and the USA reporting rates above the mean for HICs. In HICs, the most frequently reported association with stillbirth is placental dysfunction. Placental dysfunction may be evident clinically as fetal growth restriction (FGR) and small-for-dates infants. It can be caused by placental abruption or hypertensive disorders of pregnancy and many other disorders and factorsPlacental abnormalities are noted in 11% to 65% of stillbirths. Identification of FGA is difficult in utero. Small-for-gestational age (SGA), as assessed after birth, is the most commonly used surrogate measure for this outcome. The degree of SGA is associated with the likelihood of FGR; 30% of infants with a birthweight < 10th centile are thought to be FGR, while 70% of infants with a birthweight < 3rd centile are thought to be FGR. Critically, SGA is the most significant antenatal risk factor for a stillborn infant. Correct identification of SGA infants is associated with a reduction in the perinatal mortality rate. However, currently used tests, such as measurement of symphysis-fundal height, have a low reported sensitivity and specificity for the identification of SGA infants.

OBJECTIVES

The primary objective was to assess and compare the diagnostic accuracy of ultrasound assessment of fetal growth by estimated fetal weight (EFW) and placental biomarkers alone and in any combination used after 24 weeks of pregnancy in the identification of placental dysfunction as evidenced by either stillbirth, or birth of a SGA infant. Secondary objectives were to investigate the effect of clinical and methodological factors on test performance.

SEARCH METHODS

We developed full search strategies with no language or date restrictions. The following sources were searched: MEDLINE, MEDLINE In Process and Embase via Ovid, Cochrane (Wiley) CENTRAL, Science Citation Index (Web of Science), CINAHL (EBSCO) with search strategies adapted for each database as required; ISRCTN Registry, UK Clinical Trials Gateway, WHO International Clinical Trials Portal and ClinicalTrials.gov for ongoing studies; specialist abstract and conference proceeding resources (British Library's ZETOC and Web of Science Conference Proceedings Citation Index). Search last conducted in Ocober 2016.

SELECTION CRITERIA

We included studies of pregnant women of any age with a gestation of at least 24 weeks if relevant outcomes of pregnancy (live birth/stillbirth; SGA infant) were assessed. Studies were included irrespective of whether pregnant women were deemed to be low or high risk for complications or were of mixed populations (low and high risk). Pregnancies complicated by fetal abnormalities and multi-fetal pregnancies were excluded as they have a higher risk of stillbirth from non-placental causes. With regard to biochemical tests, we included assays performed using any technique and at any threshold used to determine test positivity.

DATA COLLECTION AND ANALYSIS

We extracted the numbers of true positive, false positive, false negative, and true negative test results from each study. We assessed risk of bias and applicability using the QUADAS-2 tool. Meta-analyses were performed using the hierarchical summary ROC model to estimate and compare test accuracy.

MAIN RESULTS

We included 91 studies that evaluated seven tests - blood tests for human placental lactogen (hPL), oestriol, placental growth factor (PlGF) and uric acid, ultrasound EFW and placental grading and urinary oestriol - in a total of 175,426 pregnant women, in which 15,471 pregnancies ended in the birth of a small baby and 740 pregnancies which ended in stillbirth. The quality of included studies was variable with most domains at low risk of bias although 59% of studies were deemed to be of unclear risk of bias for the reference standard domain. Fifty-three per cent of studies were of high concern for applicability due to inclusion of only high- or low-risk women.Using all available data for SGA (86 studies; 159,490 pregnancies involving 15,471 SGA infants), there was evidence of a difference in accuracy (P < 0.0001) between the seven tests for detecting pregnancies that are SGA at birth. Ultrasound EFW was the most accurate test for detecting SGA at birth with a diagnostic odds ratio (DOR) of 21.3 (95% CI 13.1 to 34.6); hPL was the most accurate biochemical test with a DOR of 4.78 (95% CI 3.21 to 7.13). In a hypothetical cohort of 1000 pregnant women, at the median specificity of 0.88 and median prevalence of 19%, EFW, hPL, oestriol, urinary oestriol, uric acid, PlGF and placental grading will miss 50 (95% CI 32 to 68), 116 (97 to 133), 124 (108 to 137), 127 (95 to 152), 139 (118 to 154), 144 (118 to 161), and 144 (122 to 161) SGA infants, respectively. For the detection of pregnancies ending in stillbirth (21 studies; 100,687 pregnancies involving 740 stillbirths), in an indirect comparison of the four biochemical tests, PlGF was the most accurate test with a DOR of 49.2 (95% CI 12.7 to 191). In a hypothetical cohort of 1000 pregnant women, at the median specificity of 0.78 and median prevalence of 1.7%, PlGF, hPL, urinary oestriol and uric acid will miss 2 (95% CI 0 to 4), 4 (2 to 8), 6 (6 to 7) and 8 (3 to 13) stillbirths, respectively. No studies assessed the accuracy of ultrasound EFW for detection of pregnancy ending in stillbirth.

AUTHORS' CONCLUSIONS

Biochemical markers of placental dysfunction used alone have insufficient accuracy to identify pregnancies ending in SGA or stillbirth. Studies combining U and placental biomarkers are needed to determine whether this approach improves diagnostic accuracy over the use of ultrasound estimation of fetal size or biochemical markers of placental dysfunction used alone. Many of the studies included in this review were carried out between 1974 and 2016. Studies of placental substances were mostly carried out before 1991 and after 2013; earlier studies may not reflect developments in test technology.

Color Doppler sonography of the aortic isthmus in intrauterine growth-restricted fetuses and normal fetuses

Intrauterine growth restriction is associated with a significant increase in morbidity and perinatal mortality, and increases the likelihood of fetal death, asphyxia, meconium aspiration, hypoglycemia, and neonatal hypothermia. The aim of this study was to determine aortic isthmus flow difference by using color doppler sonography in Intrauterine growth restriction and normal fetuses. The data presented were obtained from 30 mothers, who referred to the radiology department of Akbarabadi Hospital of Tehran with a diagnosis of intrauterine growth restriction. An ultrasound was performed to determine the status of placenta, fetus, and amniotic fluid. The umbilical arterial doppler assessment was used to confirm diagnosis of intrauterine growth restriction. Thirteen (43.3%) were nulliparous mothers and 17 (56.7%) were multiparous mothers. 30 pregnant women with healthy fetuses were enrolled as control group. According to the ultrasound findings, Dactus Venus wave type was recorded in intrauterine growth restriction fetuses, which was reported as normal (26 subjects; 86.7%) and abnormal (4 subjects; 13.3%). All together, this study provides appropriate guidance to use doppler for delivery timing and to control risk factors.

Cognitive ability in adolescents born small for gestational age: Associations with fetal growth velocity, head circumference and postnatal growth

BACKGROUND

Small size at birth may be associated with impaired cognitive ability later in life. The aim of this study was to examine the effect of being born small for gestational age (SGA), with or without intrauterine growth restriction (IUGR) on cognitive ability in late adolescence.

STUDY DESIGN

A follow-up study of a former cohort included 123 participants (52 males); 47 born SGA and 76 born appropriate for gestational age (AGA). Fetal growth velocity (FGV) was determined by serial ultrasound measurements during the third trimester. A control group matched for age and birthplace was included. The original Wechsler Adult Intelligence Scale (WAIS) was administered, and verbal, performance and full-scale Intelligence Quotient (IQ) scores were calculated.

RESULTS

There was no difference in IQ between adolescents born SGA and AGA. FGV or IUGR during the third trimester did not influence cognitive ability in late adolescence. Full-scale IQ was positively related to head circumference (HC) in adolescence (B: 1.30, 95% CI: 0.32-2.28, p=0.01). HC at birth and three months was positively associated with full-scale IQ. Catch-up growth in the group of SGA children was associated with a significantly increased height, larger HC, increased levels of insulin-like growth factor-I (IGF-I) and increased full-scale IQ compared to those born SGA without catch-up growth.

CONCLUSION

SGA and IUGR may not be harmful for adult cognitive ability, at least not in individuals born at near-term. However, known risk factors of impaired fetal growth may explain the link between early growth and cognitive ability in adulthood.

Ultrasound for fetal assessment in early pregnancy

BACKGROUND

Diagnostic ultrasound is a sophisticated electronic technology, which utilises pulses of high-frequency sound to produce an image. Diagnostic ultrasound examination may be employed in a variety of specific circumstances during pregnancy such as after clinical complications, or where there are concerns about fetal growth. Because adverse outcomes may also occur in pregnancies without clear risk factors, assumptions have been made that routine ultrasound in all pregnancies will prove beneficial by enabling earlier detection and improved management of pregnancy complications. Routine screening may be planned for early pregnancy, late gestation, or both. The focus of this review is routine early pregnancy ultrasound.

OBJECTIVES

To assess whether routine early pregnancy ultrasound for fetal assessment (i.e. its use as a screening technique) influences the diagnosis of fetal malformations, multiple pregnancies, the rate of clinical interventions, and the incidence of adverse fetal outcome when compared with the selective use of early pregnancy ultrasound (for specific indications).

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 March 2015) and reference lists of retrieved studies.

SELECTION CRITERIA

Published, unpublished, and ongoing randomised controlled trials that compared outcomes in women who experienced routine versus selective early pregnancy ultrasound (i.e. less than 24 weeks' gestation). We have included quasi-randomised trials.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy. We used the Review Manager software to enter and analyse data.

MAIN RESULTS

Routine/revealed ultrasound versus selective ultrasound/concealed: 11 trials including 37,505 women. Ultrasound for fetal assessment in early pregnancy reduces the failure to detect multiple pregnancy by 24 weeks' gestation (risk ratio (RR) 0.07, 95% confidence interval (CI) 0.03 to 0.17; participants = 295; studies = 7), moderate quality of evidence). Routine scans improve the detection of major fetal abnormality before 24 weeks' gestation (RR 3.46, 95% CI 1.67 to 7.14; participants = 387; studies = 2,moderate quality of evidence). Routine scan is associated with a reduction in inductions of labour for 'post term' pregnancy (RR 0.59, 95% CI 0.42 to 0.83; participants = 25,516; studies = 8), but the evidence related to this outcome is of low quality, because most of the pooled effect was provided by studies with design limitation with presence of heterogeneity (I² = 68%). Ultrasound for fetal assessment in early pregnancy does not impact on perinatal death (defined as stillbirth after trial entry, or death of a liveborn infant up to 28 days of age) (RR 0.89, 95% CI 0.70 to 1.12; participants = 35,735; studies = 10, low quality evidence). Routine scans do not seem to be associated with reductions in adverse outcomes for babies or in health service use by mothers and babies. Long-term follow-up of children exposed to scan in utero does not indicate that scans have a detrimental effect on children's physical or cognitive development.The review includes several large, well-designed trials but lack of blinding was a problem common to all studies and this may have an effect on some outcomes. The quality of evidence was assessed for all review primary outcomes and was judged as moderate or low. Downgrading of evidence was based on including studies with design limitations, imprecision of results and presence of heterogeneity.

AUTHORS' CONCLUSIONS

Early ultrasound improves the early detection of multiple pregnancies and improved gestational dating may result in fewer inductions for post maturity. Caution needs to be exercised in interpreting the results of aspects of this review in view of the fact that there is considerable variability in both the timing and the number of scans women received.

Poor neonatal acid-base status in term fetuses with low cerebroplacental ratio

OBJECTIVE

To determine whether small- and appropriate-for-gestational-age (SGA and AGA) term fetuses with a low cerebroplacental ratio (CPR) have worse neonatal acid-base status than those with normal CPR.

METHODS

This was a retrospective study of 2927 term fetuses divided into groups according to birth-weight centile and CPR multiple of the median. The acid-base status at birth as determined by arterial and venous umbilical cord blood pH was compared between weight-centile groups with and without low CPR.

RESULTS

CPR was better correlated with umbilical cord blood pH (arterial pH, r(2)  = 0.008, P < 0.0001 and venous pH, r(2)  = 0.01, P < 0.0001) than was birth weight (arterial pH, r(2)  = 0.001, P =0.180 and venous pH, r(2)  = 0.005, P < 0.001). AGA fetuses with low CPR were more academic than were those with normal CPR (P = 0.0359 and 0.0006, respectively, for arterial and venous pH).

CONCLUSIONS

The findings of this study demonstrate that low CPR in AGA fetuses is an equally important marker of low neonatal pH secondary to placental underperfusion as is being SGA. Although the relative importance of low CPR and birth weight in identifying pregnancies at risk of placental hypoxemia and adverse fetal and neonatal outcome remains to be determined, this finding may be of particular value in the prediction and prevention of stillbirth and long-term neurodevelopmental disability.

Impact of birth weight and early infant weight gain on insulin resistance and associated cardiovascular risk factors in adolescence

Background

Low birth weight followed by accelerated weight gain during early childhood has been associated with adverse metabolic and cardiovascular outcomes later in life. The aim of this study was to examine the impact of early infant weight gain on glucose metabolism and cardiovascular risk factors in adolescence and to study if the effect differed between adolescents born small for gestational age (SGA) vs. appropriate for gestational age (AGA).

Methodology/Principal Findings

Data from 30 SGA and 57 AGA healthy young Danish adolescents were analysed. They had a mean age of 17.6 years and all were born at term. Data on early infant weight gain from birth to three months as well as from birth to one year were available in the majority of subjects. In adolescence, glucose metabolism was assessed by a simplified intravenous glucose tolerance test and body composition was assessed by dual-energy X-ray absorptiometry. Blood pressures as well as plasma concentrations of triglycerides and cholesterol were measured. Early infant weight gain from birth to three months was positively associated with the fasting insulin concentration, HOMA-IR, basal lipid levels and systolic blood pressure at 17 years. There was a differential effect of postnatal weight gain on HOMA-IR in AGA and SGA participants (P for interaction = 0.03). No significant associations were seen between postnatal weight gain and body composition or parameters of glucose metabolism assessed by the simplified intravenous glucose tolerance test. In subgroup analysis, all associations with early infant weight gain were absent in the AGA group, but the associations with basal insulin and HOMA-IR were still present in the SGA group.

Conclusion

This study suggests that accelerated growth during the first three months of life may confer an increased risk of later metabolic disturbances – particularly of glucose metabolism – in individuals born SGA.

Ultrasound for fetal assessment in early pregnancy

BACKGROUND

Diagnostic ultrasound is a sophisticated electronic technology, which utilises pulses of high frequency sound to produce an image. Diagnostic ultrasound examination may be employed in a variety of specific circumstances during pregnancy such as after clinical complications, or where there are concerns about fetal growth. Because adverse outcomes may also occur in pregnancies without clear risk factors, assumptions have been made that routine ultrasound in all pregnancies will prove beneficial by enabling earlier detection and improved management of pregnancy complications. Routine screening may be planned for early pregnancy, late gestation, or both. The focus of this review is routine early pregnancy ultrasound.

OBJECTIVES

To assess whether routine early pregnancy ultrasound for fetal assessment (i.e. its use as a screening technique) influences the diagnosis of fetal malformations, multiple pregnancies, the rate of clinical interventions, and the incidence of adverse fetal outcome when compared with the selective use of early pregnancy ultrasound (for specific indications).

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (September 2009).

SELECTION CRITERIA

Published, unpublished, and ongoing randomised controlled trials that compared outcomes in women who experienced routine versus selective early pregnancy ultrasound (i.e. less than 24 weeks' gestation). We have included quasi-randomised trials.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data for each included study. We used the Review Manager software to enter and analyse data.

MAIN RESULTS

Routine/revealed ultrasound versus selective ultrasound/concealed: 11 trials including 37505 women. Ultrasound for fetal assessment in early pregnancy reduces the failure to detect multiple pregnancy by 24 weeks' gestation (risk ratio (RR) 0.07, 95% confidence interval (CI) 0.03 to 0.17). Routine scan is associated with a reduction in inductions of labour for 'post term' pregnancy (RR 0.59, 95% CI 0.42 to 0.83). Routine scans do not seem to be associated with reductions in adverse outcomes for babies or in health service use by mothers and babies. Long-term follow up of children exposed to scan in utero does not indicate that scans have a detrimental effect on children's physical or cognitive development.

AUTHORS' CONCLUSIONS

Early ultrasound improves the early detection of multiple pregnancies and improved gestational dating may result in fewer inductions for post maturity. Caution needs to be exercised in interpreting the results of aspects of this review in view of the fact that there is considerable variability in both the timing and the number of scans women received.

WITHDRAWN: Ultrasound for fetal assessment in early pregnancy

BACKGROUND

Advantages of early pregnancy ultrasound screening are thought to be more accurate calculation of gestational age, earlier identification of multiple pregnancies, and diagnosis of non-viable pregnancies and certain fetal malformations.

OBJECTIVES

The objective of this review was to assess the use of routine (screening) ultrasound compared with the selective use of ultrasound in early pregnancy (ie before 24 weeks).

SEARCH STRATEGY

The Cochrane Pregnancy and Childbirth Group trials register and the Cochrane Controlled Trials Register (up to June 2001) were searched.

SELECTION CRITERIA

Adequately controlled trials of routine ultrasound imaging in early pregnancy.

DATA COLLECTION AND ANALYSIS

One reviewer assessed trial quality and extracted data. Study authors were contacted for additional information.

MAIN RESULTS

Nine trials were included. The quality of the trials was generally good. Routine ultrasound examination was associated with earlier detection of multiple pregnancies (twins undiagnosed at 26 weeks, odds ratio 0.08, 95% confidence interval 0.04 to 0.16) and reduced rates of induction of labour for post-term pregnancy (odds ratio 0.61, 95% confidence interval 0.52 to 0.72). There were no differences detected for substantive clinical outcomes such as perinatal mortality (odds ratio 0.86, 95% confidence interval 0.67 to 1.12). Where detection of fetal abnormality was a specific aim of the examination, the number of terminations of pregnancy for fetal anomaly increased.

AUTHORS' CONCLUSIONS

Routine ultrasound in early pregnancy appears to enable better gestational age assessment, earlier detection of multiple pregnancies and earlier detection of clinically unsuspected fetal malformation at a time when termination of pregnancy is possible. However, the benefits for other substantive outcomes are less clear.

Customised fetal growth chart: A systematic review

Customised fetal growth chart is used to individualise fetal weight for gestational age by adjusting for physiological variables known to affect birth weight and growth. Compared with the standard population-based growth chart, the customised growth chart allows for better distinction between normal and abnormal smallness and reduces the false positive and false negative diagnosis of fetal growth restriction. The charts are currently being introduced into clinical practice in the West Midlands as well as in several units around the country. A Medline and systematic review search from 1980 to 2004 was performed in order to collect information and evidence on the use of customised growth chart and its effect on perinatal outcome.

Categories of intrauterine growth retardation

Originally all low birthweight infants were considered to be premature. When prematurity was redefined in terms of gestational age (SGA) and not preterm. With the large scale collection of obstetric data the distributions of birthweight at different gestational ages were described and from these, infants who were SGA could be defined. SGA became synonymous with terms such as growth retardation, but it soon became appearent that the two were not necessarily interchangeable. Scott and Usher found that it was the degree of soft tissue wasting rather than birthweight that related to poor perinatal outcome. Miller and Hassanein stated that: “birthweight by itself is not a valid measure of fetal growth impairment”. They used Rorher’s Ponderal Index (weight (g) × 100/length (cm)) to diagnose the malnourished or excessively wasted infants with reduced soft tissue mass. Most studies of intrauterine growth retardation (IUGR) still use low birthweight for gestational age centile as their only definition of IUGR or only study infants who have a low birthweight. Altman and Hytten expressed disquiet about this definition and stated: “There is now an urgent need to establish true measures of fetal growth from which deviations indicating genuine growth retardation can be derived” and that “it is particularly important that some reliable measures of outcome should be established”. In large series of term deliveries published recently, two groups of IUGR infants with different growth patterens have been identified. These studies confirm that birthweight alone is inadequate to define the different types of IUGR. They established that low Ponderal Index (PI) is a measure of IUGR associated with an increased incidence of perinatal problems and that it is time to re-evaluate IUGR in terms of the different types of aberrant fetal growth.

The effect of birthweight upon insulin resistance and associated cardiovascular risk factors in adolescence is not explained by fetal growth velocity in the third trimester as measured by repeated ultrasound fetometry

AIMS/HYPOTHESIS

Smallness for gestational age (SGA) is associated with increased risk of developing components of the metabolic syndrome. Although SGA can imply intrauterine growth restriction (IUGR), more information is required to link specific fetal growth patterns to adult outcomes.

METHODS

We examined the impact of fetal growth velocity during the third trimester (FGV) vs birthweight for gestational age on early markers of the metabolic syndrome in 123 healthy men and women (mean age 17.5 years) born at term. FGV was determined by ultrasound measurements.

RESULTS

After correction for confounders including current BMI, SGA was significantly associated with raised basal plasma insulin (+19% above appropriate for gestational age), homeostasis model assessment of insulin resistance (+21%), cholesterol:HDL-cholesterol ratio (+13%) and systolic BP (+4.8%) (all p < 0.05). Furthermore SGA was associated with increased fat mass (+9.6%) and trunk-fat per cent (+6.8%) and with reduced lean body mass as determined by dual-energy X-ray absorptiometry scans (-4.1% below appropriate for gestational age) (all p < 0.05). In contrast, IUGR in the third trimester was associated only with an elevated cholesterol:HDL-cholesterol ratio (+11% above not-IUGR).

CONCLUSIONS/INTERPRETATION

In the present study, FGV did not explain the impact of birthweight upon the metabolic phenotype in adolescence. This suggests that fetal growth prior to the third trimester or postnatal catch-up growth plays a more important role.

Increased basal and pulsatile secretion of FSH and LH in young men with 47,XXY or 46,XX karyotypes

OBJECTIVE

The regulation of normal sexual maturation and reproductive function is dependent on a precise hormonal regulation at hypothalamic, pituitary, and gonadal levels. The aim of this study was to investigate the neuroendocrine integrity of the pituitary-gonadal axis in patients with primary testicular failure due to supernumerary X chromosomes.

DESIGN

Cross-sectional study.

METHODS

In this study, 7 untreated patients with primary gonadal insufficiency due to SRY-positive 46,XX (n=4) and 46,XXY karyotypes (n=3) aged 18.8 years and 25 age-matched healthy controls participated. Reproductive hormones, testicular size, and overnight LH and FSH serum profiles and overnight urine LH and FSH excretion were determined.

RESULTS

Basal LH and FSH secretion was elevated 6.3- and 25.4-fold respectively in the patients and the amount of LH and FSH secreted per burst were 2.0- and 6.6-fold elevated. We found significantly more LH but not FSH peaks per 24 h, as estimated by the Weibull lambda analysis. There was no difference between approximate entropy ratios or Weibull gamma analyses indicating comparable orderliness and regularity of LH and FSH secretion. Overnight urinary LH and FSH excretion was significantly elevated in patients compared with controls and correlated significantly with calculated total overnight LH and FSH secretion respectively, thus validating deconvolution.

CONCLUSION

In this group of patients with severe hypergonadotropic hypogonadism due to a supernumerary X chromosome, higher basal, pulsatile, and total LH and FSH secretion were associated with significantly more LH peaks per 24 h in comparison with healthy controls. Thus, our data indicate that in patients with Klinefelter syndrome and XX male karyotypes the entire hypothalamic-pituitary-gonadal axis has undergone functional changes.

Fetal growth velocity, size in early life and adolescence, and prediction of bone mass: association to the GH-IGF axis

Poor growth in early life is associated with numerous adverse outcomes later in life. In 123 adolescents 16-18 yr of age, the previous findings of a positive relation between size in early life and later bone mass was confirmed. These associations were mediated by the current height and weight, but it was not confirmed that alterations of the GH-IGF axis cause this.

INTRODUCTION

Numerous studies have found associations between low birth weight and disease later in life, including decreased bone mass.

MATERIALS AND METHODS

A longitudinal cohort of 16- to 19-year-old adolescents (n = 123) with data on third trimester fetal growth velocity (FGV) was assessed by serial ultrasound measurements, birth weight (BW), and weight at 1 yr. A follow-up study included DXA scan, anthropometric measurements, and measurements of the growth hormone (GH) -IGF-I axis in a representative subpopulation (n = 30).

RESULTS

BW and weight at 1 yr were positively associated with whole body BMC (p = 0.02 and p < 0.0001, respectively), lumbar spine BMC (p = 0.001 and p = 0.03, respectively), and lumbar spine BMD (p = 0.04). After correction for adolescent height and weight, no association remained significant. There was no relation between IGF-I and IGF binding protein 3 (IGFBP-3) levels in adolescence and size in early life or bone mass. In the subpopulation, GH secretion (median, 2.58 versus 4.05), GH pulse mass (median, 10.7 versus 19.4 mU/liter), and total GH (median, 74.9 versus 108.8 mU/liter/12 h) were decreased in the small for gestational age (SGA) group compared with the appropriate for gestational age (AGA) group; this did not reach statistical significance. Likewise, there were no differences in IGF-I, IGF-II, and IGFBP-1, -2, and -3 levels between the SGA and AGA groups. A statistically significant positive association between FGV and adolescent IGF-II was found (B = 199.9, p = 0.006). Significant negative associations between GH measurement and BMC, as well as BMD, were found (B = -0.008, p = 0.005 and B = -0.008, p = 0.006, respectively).

CONCLUSIONS

This study confirms the previous findings of a positive relation between size in early life and later BMC, an association apparently independent of the distal part of the GH/IGF-I axis. However, this association may be mediated mainly by postnatal growth determining size of the skeletal envelope rather than an effect of fetal programming on bone mass per se.

The impact of maternal smoking on fetal and infant growth

BACKGROUND

Low birth weight is associated with accelerated postnatal growth and adverse adult health outcomes. Maternal smoking is a major risk factor for low birth weight. This study aims to assess: Pre- and postnatal growth associated with maternal smoking compared to other risk factors for low birth weight. The effect of reduction of maternal smoking on growth.

SUBJECTS

A cohort (n=269) followed with ultrasound measurements in the third trimester and postnatal anthropometric measurements until 6 months of age. Mothers were interviewed about their smoking habits at 18 and 28 weeks of pregnancy.

RESULTS

Maternal smoking was associated with a greater reduction in birth length SDS than other causes of equally reduced birth weight (mean difference: -0.25 SDS, P=0.013). The adjustment of gestational age, based on bi-parietal diameter at an early dating scan, indicated that mothers who reduced smoking carried smaller fetuses than mothers who continued to smoke heavily (mean difference=2.6 days, P=0.012). Birth weights in these two groups were similar (P=0.87). However at 3 months of age, reduced smoking was associated with lower weight (mean difference=-0.38 SDS, P=0.045).

CONCLUSIONS

Maternal smoking was associated with a reduction of linear growth, which was more marked than that of other risk factors, and which seemed to occur before the 3rd trimester. The results indicated a beneficial effect of reduction of smoking upon third trimester growth, and that the decision to reduce smoking in mid-pregnancy may be influenced by early fetal size.

Disproportionate Intrauterine Growth Intervention Trial At Term: DIGITAT

Background

Around 80% of intrauterine growth restricted (IUGR) infants are born at term. They have an increase in perinatal mortality and morbidity including behavioral problems, minor developmental delay and spastic cerebral palsy. Management is controversial, in particular the decision whether to induce labour or await spontaneous delivery with strict fetal and maternal surveillance. We propose a randomised trial to compare effectiveness, costs and maternal quality of life for induction of labour versus expectant management in women with a suspected IUGR fetus at term.

Methods/design

The proposed trial is a multi-centre randomised study in pregnant women who are suspected on clinical grounds of having an IUGR child at a gestational age between 36+0 and 41+0 weeks. After informed consent women will be randomly allocated to either induction of labour or expectant management with maternal and fetal monitoring. Randomisation will be web-based. The primary outcome measure will be a composite neonatal morbidity and mortality. Secondary outcomes will be severe maternal morbidity, maternal quality of life and costs. Moreover, we aim to assess neurodevelopmental and neurobehavioral outcome at two years as assessed by a postal enquiry (Child Behavioral Check List-CBCL and Ages and Stages Questionnaire-ASQ). Analysis will be by intention to treat. Quality of life analysis and a preference study will also be performed in the same study population. Health technology assessment with an economic analysis is part of this so called Digitat trial (Disproportionate Intrauterine Growth Intervention Trial At Term). The study aims to include 325 patients per arm.

Discussion

This trial will provide evidence for which strategy is superior in terms of neonatal and maternal morbidity and mortality, costs and maternal quality of life aspects. This will be the first randomised trial for IUGR at term.

Trial registration

Dutch Trial Register and ISRCTN-Register: ISRCTN10363217.

The presence of the d3-growth hormone receptor polymorphism is negatively associated with fetal growth but positively associated with postnatal growth in healthy subjects

CONTEXT

A common polymorphism in the GH receptor (GHR) gene has been linked to increased growth response in GH-treated patients. No former study has focused on the association to prenatal growth.

OBJECTIVE

The aim of the study was to evaluate the association between the d3-GHR isoforms and spontaneous pre- and postnatal growth.

DESIGN

A prospective study was conducted on third-trimester fetal growth velocity (FGV), birth weight, birth length, and postnatal growth.

SETTING

The study was conducted at Copenhagen University Hospital.

PARTICIPANTS

A total of 115 healthy adolescents were divided into those born small for gestational age (SGA) and appropriate for gestational age with or without intrauterine growth restriction.

MAIN OUTCOME MEASURES

FGV was measured by serial ultrasonography, birth weight, birth length, and adolescent height. Isoforms of the d3-GHR gene (fl/fl, d3/fl, and d3/d3) were determined.

RESULTS

The prevalence of the d3-GHR isoforms was 50% but differed among the groups (P = 0.006), with a high prevalence (88%) in the group born SGA with verified intrauterine growth restriction. The d3-GRH allele were associated with decreased third-trimester FGV (P = 0.05) in SGA subjects. In the entire cohort, carriers of the d3-GHR allele had a significantly increased height (-0.10 vs. 0.34 SD score; P = 0.017) and change in height from birth to adolescence compared with carriers of the full-length GHR allele (0.57 vs. -0.02 SD score; P = 0.005).

CONCLUSIONS

This study showed an increased spontaneous postnatal growth velocity in the carriers of the d3-GHR allele. Interestingly, we found the opposite effect on prenatal growth in the SGA group, with a decreased FGV in carriers of the d3-GHR allele.

Pituitary-gonadal function in adolescent males born appropriate or small for gestational age with or without intrauterine growth restriction

CONTEXT

Being born small for gestational age (SGA) is suggested to influence female pituitary-gonadal axis, but only a few studies have focused on male pituitary-gonadal function.

OBJECTIVE

Our objective was to evaluate the influence of fetal growth rate on male reproductive function.

DESIGN

We conducted a follow-up study of a prospective study with data on third trimester fetal growth velocity and birth weight.

SETTING

The study was conducted at Copenhagen University Hospital.

PARTICIPANTS

Fifty-two healthy adolescent males participated. They were divided into those born appropriate for gestational age (AGA) and SGA, with or without intrauterine growth restriction.

MAIN OUTCOME MEASURES

Pubertal stage, testicular size, and reproductive hormones were determined. Overnight 20-min LH and FSH profiles and overnight urine LH and FSH were determined in an additional study (n=30).

RESULTS

No significant differences were found in testosterone levels (19.2 vs. 18.9 nmol/liter), inhibin B levels (186.5 vs. 188.0 pg/ml), or LH/testosterone ratio (0.15 vs. 0.18) between AGA and SGA, respectively. No significant differences in overnight secretory patterns of gonadotropins or testicular size and morphology were determined by ultrasonography between AGA and SGA. Fetal growth velocity did not influence any of the reproductive hormone levels. Overnight urinary LH and FSH excretion correlated statistically significantly with overnight LH (r=0.50; P=0.02) and FSH (r=0.44; P=0.04) secretion, respectively.

CONCLUSION

Poor third trimester growth and/or low birth weight had no effect on subsequent male reproductive hormones. Contrasting a previous study, we found no difference in testosterone or inhibin B levels between SGA and AGA, suggesting that testicular function was not impaired in adolescent males born after compromised fetal growth.

Analysis of Z-score distribution for the quality control of fetal ultrasound measurements at 20-24 weeks

OBJECTIVES

To develop and evaluate the feasibility of Z-score distribution-based quality assessment for fetal biometry at 20-24 gestational weeks.

METHODS

Four sonographers measured fetal biparietal diameter, head circumference, abdominal circumference and femur length in unselected pregnancies undergoing routine sonography at 20-24 weeks in our center between June 2001 and January 2004. All measurements were transformed into Z-scores. Distributions of Z-scores were compared with the expected standard normal distribution based on mean, SD and the Kolmogorov-Smirnov test. Modelling was performed to assess the sensitivity, specificity and Youden's index (sensitivity + specificity - 1) of each sonographer, reflecting their ability to detect fetuses with abnormal biometry in our population.

RESULTS

A total of 5241 ultrasound examinations were included. None of the Z-score distributions could be considered similar to the standard normal distribution: means of Z-scores ranged from -0.604 to 0.73 and the SD ranged from 0.726 to 0.896. Sensitivity and specificity ranged from 25.31% to 68.67% and 93.44% to 100%, respectively; Youden's index ranged from 0.25 to 0.69.

CONCLUSION

Analysis of Z-score distribution can be used to assess the quality of fetal measurements. Several indices can be extracted from this analysis in order to improve quality assessment of fetal biometry measured by ultrasound.

A Framework for the Development of MaternalQuality of Care Indicators

BACKGROUND

In collaboration with the California Department of Health Maternal and Child Health Branch, the authors formed a Working Group to identify potential clinical indicators that could be used to inform decision making regarding maternal health care quality.

OBJECTIVE

To develop potential indicators for the assessment of maternal health care quality.

MATERIALS AND METHODS

A Working Group was convened to review information from the published literature and expert opinion. Selection of potential indicators was guided by the following goals: 1) To identify key areas for routine aggregate monitoring; 2) To include perspectives of relevant stakeholders in maternal health care services; 3) To include measures that are comprehensive and reflect a balance between maternal and fetal interests; and 4) To develop measures that would be valid, generalizable, mutable, and feasible.

RESULTS

Ninety potential indicators were identified. Each underwent a thorough review based on: its definition, objective, and validity; its contribution to innovation; the cost and timeliness of implementation; its feasibility, acceptability, and potential effectiveness; and its compatibility with ethics, values, and social policy. This process yielded 24 final indicators from the following categories: Health Status and Access (e.g., availability of 24 h inpatient anesthesia); Preconception and Interconception Care (e.g., Pap smear use); Antenatal Care (e.g., hospitalization for uncontrolled diabetes or pyelonephritis); Labor and Delivery Care (e.g., chorioamnionitis or obstetrical hemorrhage), and Postpartum Care (e.g., rate of postpartum visits).

CONCLUSIONS

These potential indicators, representative of the women's health continuum, can serve as a foundation to structure the development of consensus and methods for maternal health care quality assessment.

US evaluation of fetal growth: prediction of neonatal outcomes

PURPOSE

To determine whether fetal growth measured at serial ultrasonographic (US) examinations can predict neonatal morbidity, independent of whether gestational age is known.

MATERIALS AND METHODS

Women (n = 321) who had singleton pregnancies and underwent two or more second- or third-trimester obstetric US examinations were included in a retrospective cohort analysis. Inadequate fetal growth was defined as growth at or below the 10th percentile. The relative risk of each poor outcome was calculated for fetuses with inadequate growth, compared with the risk for fetuses with normal growth.

RESULTS

Inadequate fetal growth was associated with 3.9 times the risk of a birth weight less than 2,500 g, 17.7 times the risk of a birth weight less than the 3rd percentile for gestational age, 2.3 times the risk of preterm birth, 2.6 times the risk of a long newborn hospital stay, and 3.6 times the risk of neonatal intensive care unit admission. After adjusting for confounding variables, including fetal weight, fetal growth remained a significant predictor of small birth size and poor outcomes. Inadequate growth predicted the risk of poor outcomes, even when gestational age was unknown. When inadequate growth was used to identify fetuses at risk, 21%-67% of neonates who were small at birth or had poor outcomes were identified at false-positive rates of only 5%-9%. For all outcomes, inadequate growth enabled identification of more fetuses with poor birth outcomes than low estimated fetal weight.

CONCLUSION

Morbidity is significantly increased among fetuses who demonstrate less than expected growth. Growth between two US examinations can be used to estimate the risk of neonatal morbidity, even when gestational age is unknown.

Sonographic estimate of birth weight: relative accuracy of sonographers versus maternal-fetal medicine specialists

OBJECTIVE

To compare the relative accuracy of predicting birth weight among registered diagnostic medical sonographers versus maternal-fetal medicine specialists.

STUDY DESIGN

Over 7 months all patients who delivered within 2 weeks and had sonographic measurements of femur length and head and abdominal circumferences by sonographers and physicians were included in the analysis. The exclusion criteria were multiple gestation and anomalous fetuses. Receiver operating-characteristic curves (ROC) were constructed to determine the ability to detect intrauterine growth restriction (IUGR; birth weight < 2,500 g) and macrosomia (birth weight > or = 4,000 g) among term (gestational age > or = 37 weeks) parturients. A level of p < 0.05 was considered significant.

RESULTS

Among 365 patients recruited, the mean gestational age was 37.3 +/- 2.4 weeks with a mean birth weight of 3,083 +/- 72.5 g. Among term patients the prevalence of IUGR was 7.5% (18/238) and of macrosomia 12% (29/238). A significantly higher percentage of predictions were within 10% of the birth weight when obtained by sonographers (70%) than physicians (54%; p < 0.0001). Registered sonographers were significantly more likely to detect IUGR than the specialists (area under the ROC curves 0.97 +/- 0.02 vs. 0.92 +/- 0.02, respectively; p = 0.02). Both groups had similar accuracy in detecting macrosomic fetuses (area under the ROC curves 0.92 +/- 0.02 for sonographers and 0.90 +/- 0.02 for physicians; p = 0.40).

CONCLUSIONS

Prediction of birth weight is significantly more accurate when sonographers rather than maternal-fetal medicine specialists perform the ultrasonographic examination.

Serial measurements of serum human placental lactogen (hPL) and serial ultrasound examinations in the evaluation of fetal growth

Serial serum hPL measurements and serial ultrasound fetometry were compared in the evaluation of fetal growth by relating these two parameters to size at birth and to clinical factors known to influence size at birth. The data were from a prospective study of 1000 consecutive pregnant women considered to be at risk for fetal growth retardation with retrospective analysis. Serum hPL was measured by radioimmunoassay and fetal weight estimated by ultrasound every 3 weeks during the last trimester. hPL values were expressed as multiples of the median (MoM) and linear regression analysis of the hPL MoM values was carried out for each pregnancy to find the slope of the line (hPL-slope); at least 3 serum hPL values were required. The estimated fetal weight and weight-for-age at birth was expressed in Z-scores. The individual intrauterine growth velocity was calculated by regression analysis and expressed as change in Z-score for 12 weeks. At least two ultrasound measurements over an interval of at least 42 days were used to estimate the fetal growth velocity. In 588 women the file was complete. The main outcome measures were the individual mean hPL, hPL-slope, fetal growth velocity, birth weight deviation, smoking in pregnancy and diagnosis of preeclampsia. A significant correlation was found between the hPL-slope and the intrauterine fetal growth velocity (r=0.34), and between hPL-slope and birth weight deviation (r=0.32). Mean hPL was correlated to birth weight deviation (r=0.27), but only very weakly to intrauterine growth velocity (r=0.08). hPL-slope and intrauterine growth velocity independently predicted birth weight deviation. Heavy smoking which was stopped before the third trimester was not associated with low intrauterine growth velocity, but with a low hPL-slope. Preeclampsia was associated with a trend towards low and decreasing hPL and with an increasing intrauterine growth velocity and birth weight deviation. In conclusion the rate of change of serial hPL measurements correlated well to intrauterine fetal growth velocity in the third trimester as estimated by ultrasound and to the deviation in birth weight, but hPL seems to have a separate physiological significance, since it did not pick up when smoking was stopped and growth velocity was normalised and it did not at all detect the increased growth associated with preeclampsia.

Customized fetal weight limits for antenatal detection of fetal growth restriction

OBJECTIVE

To define cut-off limits for individually adjustable fetal weight standards for the detection of intrauterine growth restriction.

DESIGN

Retrospective study, with the outcome measures small-for-gestational age (SGA) birth weight, operative delivery for fetal distress, umbilical artery pH < 7.15, and admission to the neonatal intensive care unit.

SUBJECTS AND METHODS

Two hundred and fifteen women considered to be at increased risk of uteroplacental insufficiency were recruited to a study of serial ultrasound scans. Fetal weights were derived using standard formulae and, retrospectively, weight percentiles were calculated after individual adjustment for maternal height, weight in early pregnancy, ethnic group, parity and fetal sex.

INTRODUCTION

One or more antenatal scans indicative of fetal weight below the 10th customized percentile were predictive for a SGA neonate at birth (P < 0.001), operative delivery for fetal distress (P < 0.01) and admission to neonatal intensive care (P < 0.01) but not for a low umbilical artery pH (P = 0.6). Receiver-operator curves showed the optimal customized fetal weight percentile limit for predicting an SGA neonate to be the 18th percentile (sensitivity 83%, specificity 79%, positive predictive value 63% and negative predictive value 92%). For the prediction of operative delivery for fetal distress and admission to neonatal intensive care, the optional customized cut-off value was the 8th percentile.

CONCLUSIONS

The assessment of fetal weight using ultrasound and an individually-adjusted standard is predictive of growth restriction and perinatal events associated with hypoxia or diminished reserve. The optimal cut-off value for predicting operative delivery for fetal distress or admission to the neonatal intensive care unit suggests that the 10th customized percentile is a good limit for clinical use.

Ultrasound for fetal assessment in early pregnancy

BACKGROUND

Advantages of early pregnancy ultrasound screening are thought to be more accurate calculation of gestational age, earlier identification of multiple pregnancies, and diagnosis of non-viable pregnancies and certain fetal malformations.

OBJECTIVES

The objective of this review was to assess the use of routine (screening) ultrasound compared with the selective use of ultrasound in early pregnancy (ie before 24 weeks).

SEARCH STRATEGY

The Cochrane Pregnancy and Childbirth Group trials register and the Cochrane Controlled Trials Register (up to July 1998) were searched.

SELECTION CRITERIA

Adequately controlled trials of routine ultrasound imaging in early pregnancy.

DATA COLLECTION AND ANALYSIS

One reviewer assessed trial quality and extracted data. Study authors were contacted for additional information.

MAIN RESULTS

Nine trials were included. The quality of the trials was generally good. Routine ultrasound examination was associated with earlier detection of multiple pregnancies (twins undiagnosed at 26 weeks, odds ratio 0.08, 95% confidence interval 0.04 to 0.16) and reduced rates of induction of labour for post-term pregnancy (odds ratio 0. 61, 95% confidence interval 0.52 to 0.72). There were no differences detected for substantive clinical outcomes such as perinatal mortality (odds ratio 0.86, 95% confidence interval 0.67 to 1.12). Where detection of fetal abnormality was a specific aim of the examination, the number of terminations of pregnancy for fetal anomaly increased.

REVIEWER'S CONCLUSIONS

Routine ultrasound in early pregnancy appears to enable better gestational age assessment, earlier detection of multiple pregnancies and earlier detection of clinically unsuspected fetal malformation at a time when termination of pregnancy is possible. However the benefits for other substantive outcomes are less clear.

The fetal outcome in pregnancies with isolated reduced amniotic fluid volume in the third trimester

Our aim was to assess the outcome of pregnancies where oligohydramnios, defined by a published gestational reference range for amniotic fluid index, was the only abnormal finding at third trimester scan, and all other ultrasound parameters including biometry were within normal limits at initial scan. A retrospective case-control study was performed at The Liverpool Maternity Hospital. 103 pregnancies with reduced amniotic fluid index in the third trimester and apparently normal fetal growth profile ultrasonographically were identified from ultrasound reports throughout 1993. Pregnancies in the third trimester with normal amniotic fluid index on index scan were also identified from these reports and 103 were matched for parity, gestational age at delivery, mode of onset of labour, presentation at labour and medical conditions. Exclusion criteria were ruptured membranes, fetal abnormalities, estimated fetal weight below the fifth centile at index scan and multiple pregnancies. The outcome criteria were birthweight, Apgar scores at delivery, induction and emergency delivery for fetal reasons and admission to Neonatal Intensive Care Unit. Statistical analysis was performed by Fisher's exact test and Gart's odds ratio. Compared with controls, pregnancies in the reduced liquor group had a higher number of babies below the 5th centile (odds ratio 5.2, 95% confidence interval 1.6 to 22), a higher risk of induction for fetal reasons (odds ratio 34.4, 95% confidence interval 5.35 to 1425.5) and admission to Neonatal Intensive Care Unit (odds ratio 9.77, 95% confidence interval 1.3 to 432). Any observed difference in the need for emergency delivery due to fetal reasons was not clinically significant (odds ratio 2.16, 95% confidence interval 0.77 to 6.6) The definition used for oligohydramnios used in this study appears to identify a group of babies with a fourfold risk of low birthweight and a high risk of admission to the Neonatal Intensive Care Unit and induction of labour for fetal reasons. This would suggest that pregnancies with isolated oligohydramnios require some form of fetal monitoring and further prospective studies are required to determine the most appropriate method.

Intrauterine growth correlation to postnatal growth--influence of risk factors and complications in pregnancy

In a population of 616 pregnant women with increased risk of intrauterine growth retardation, we examined the relationship of third trimester fetal growth to maternal and pregnancy risk factors, the infants condition at birth, and postnatal growth. Intrauterine growth velocity was calculated from repeated estimations of fetal weight using ultrasound. Postnatal growth up to 3 months was measured in 313 of the infants. Intrauterine growth velocity was directly correlated to birth weight deviation (R = 0.35, P < 0.0001) and inversely correlated to postnatal growth (R = 0.21, P = 0.0001). Heavy smoking throughout pregnancy was the most pronounced factor associated with loss of fetal growth percentiles (P = 0.006), and it was also associated with postnatal catchup (P = 0.01). Infants who needed neonatal care had significantly lower intrauterine growth velocities compared to the rest of the study group; no correlation was found between intrauterine growth velocity and Apgar scores or umbilical pH. It is concluded that growth retardation in the third trimester can be identified by ultrasound fetometry, and is associated with maladaptation at birth and postnatal catchup. However, the correlations were weak suggesting that deviation at birth reflects, only to a limited degree, acceleration or deceleration of growth in the third trimester.

Receiver-operator characteristic curves for the ultrasonographic prediction of small-for-gestational-age fetuses in low-risk pregnancies

OBJECTIVE

Our purpose was to assess the accuracy of third-trimester ultrasonographic biometry in the diagnosis of small-for-gestational-age fetuses in a low-risk obstetric population.

STUDY DESIGN

A total of 1000 low-risk pregnancies were prospectively examined at 31 weeks' gestation. The diagnostic accuracy of the fetal abdominal circumference and estimated fetal weight according to 24 formulas in the literature were evaluated by the use of receiver-operator characteristic curves.

RESULTS

The incidence of a birth weight <10th percentile was 8.2%. The diagnostic accuracies of abdominal circumference and estimated fetal weight were remarkably similar. None of the 24 formulas performed significantly better than the measurement of the abdominal circumference. At a specificity of 90%, 46% of infants with a birth weight <10th percentile and five of six cases with adverse perinatal outcomes were predicted.

CONCLUSION

In a low-risk obstetric population third-trimester ultrasonographic biometry has limited value in predicting small-for-gestational-age fetuses, and estimation of fetal weight does not carry an advantage over measurement of the abdominal circumference. The optimal cutoff value remains uncertain. However, by accepting a 10% false-positive rate, half of small-for-gestational-age fetuses and most perinatal complications could be recognized.

Standards for ultrasound fetal growth velocity

OBJECTIVES

An ultrasound study to establish the nature and limits of fetal growth in a low risk population from 22 weeks of gestation until term.

DESIGN

Prospective, longitudinal ultrasound study of 274 low risk pregnancies involving organised scanning schedules with all measurements performed by one observer using the same equipment.

RESULTS

Growth velocity charts have been created for a number of ultrasound parameters including estimated fetal weight, by applying appropriate statistical methods to the serial data. The rates of growth of the biparietal diameter, femur length, abdominal area and estimated weight each have characteristic patterns demonstrating maximal growth rates at different gestations.

CONCLUSIONS

Appropriately derived and calculated ultrasound fetal growth velocity standards have been established. These data are suitable for the evaluation of ultrasonically estimated fetal growth rates in the prediction of adverse perinatal outcome and the further investigation of the role of the intrauterine environment in the origin of adult disease.

Screening for the small fetus: a study of the relative efficacies of ultrasound biometry and symphysiofundal height

In this study 3 different methods of screening for birth-weight < 10th percentile in pregnancy were evaluated both individually and in combination; 1,135 women with singleton pregnancies were studied. Measurements of symphysiofundal height by tape measure, and amniotic fluid index and fetal abdominal circumference by ultrasound imaging, were made at 18, 24, 28, 34 and 38 weeks. At none of these gestational ages did amniotic fluid index perform well as a screening test for birth-weight < 10th percentile. Combining the tests, using symphysiofundal height to select a group at high risk who then had a fetal abdominal circumference measurement, reduced the false positive rate but significantly decreased the percentage of infants diagnosed. The results of this study confirm that the most appropriate antenatal diagnostic test for birth-weight <10th percentile is ultrasound measurement of fetal abdominal circumference. Selecting pregnancies at risk by clinical measurement of symphysiofundal height will provide a lower false positive rate than a policy of performing ultrasound on all pregnancies during the third trimester, but will also reduce the sensitivity.

Prediction of birth weight by ultrasound-estimated fetal weight: a comparison between single and repeated estimates

OBJECTIVES

Ultrasound estimation of fetal weight is used for diagnosing intrauterine growth retardation. The aim of the present study was to assess the accuracy of birth weight prediction by use of a single or repeated estimations of fetal weight in the third trimester.

STUDY DESIGN

1000 pregnant women considered at risk were scheduled to ultrasound estimation of fetal weight, using Warsof's formula, at 28, 31, 34 and 37 weeks of gestation. The 421 pregnancies with term delivery and complete set of ultrasound examinations and 57 pregnancies with preterm delivery with ultrasound examination at 16 and 28 weeks and once more before delivery were included in the present analysis.

RESULTS

The accuracy of birth weight prediction improved significantly for every three weeks from 28 to 37 weeks of gestation in the term infants. Prediction based on the average of repeated weight estimates or linear extrapolation from two estimates or extrapolation by a second order polynomium fitted to four estimates did not improve accuracy compared to prediction based on the last estimate before delivery.

CONCLUSION

When more than one ultrasound estimation of fetal weight are available, prediction of birth weight in relation to gestational age should be based on the last ultrasound examination only.

A randomized controlled trial in a hospital population of ultrasound measurement screening for the small for dates baby

Poor fetal growth is an important cause of perinatal mortality and morbidity. Based on the hypothesis that early diagnosis of fetal growth problems leads to more appropriate management and therefore, improved outcome, a randomized controlled trial of ultrasound measurement was performed on 1,528 women booked through a hospital antenatal clinic. This compared a number of perinatal outcomes between the group who had a routine 2-stage examination (early dating and 34-week scan) and a group who had only a dating scan and then additional scans as generated by their clinical situations. No significant differences could be found between the groups when these perinatal outcomes were considered. These results mirror previously published randomized controlled trials. Selection of women for third trimester ultrasound examination for suspected fetal growth problems should be based on careful clinical assessment and should not be routine.

Effect of prenatal ultrasound screening on perinatal outcome. RADIUS Study Group

BACKGROUND

Many clinicians advocate routine ultrasound screening during pregnancy to detect congenital anomalies, multiple-gestation pregnancies, fetal growth disorders, placental abnormalities, and errors in the estimation of gestational age. However, it is not known whether the detection of these conditions through screening leads to interventions that improve perinatal outcome.

METHODS

We conducted a randomized trial involving 15,151 pregnant women at low risk for perinatal problems to determine whether ultrasound screening decreased the frequency of adverse perinatal outcomes. The women randomly assigned to the ultrasound-screening group underwent one sonographic examination at 15 to 22 weeks of gestation and another at 31 to 35 weeks. The women in the control group underwent ultrasonography only for medical indications, as identified by their physicians. Adverse perinatal outcome was defined as fetal death, neonatal death, or neonatal morbidity such as intraventricular hemorrhage.

RESULTS

The mean numbers of sonograms obtained per woman in the ultrasound-screening and control groups were 2.2 and 0.6, respectively. The rate of adverse perinatal outcome was 5.0 percent among the infants of the women in the ultrasound-screening group and 4.9 percent among the infants of the women in the control group (relative risk, 1.0; 95 percent confidence interval, 0.9 to 1.2; P = 0.85). The rates of preterm delivery and the distribution of birth weights were nearly identical in the two groups. The ultrasonographic detection of congenital anomalies had no effect on perinatal outcome. There were no significant differences between the groups in perinatal outcome in the subgroups of women with post-date pregnancies, multiple-gestation pregnancies, or infants who were small for gestational age.

CONCLUSIONS

Screening ultrasonography did not improve perinatal outcome as compared with the selective use of ultrasonography on the basis of clinician judgment.

Does routine ultrasound scanning improve outcome in pregnancy? Meta-analysis of various outcome measures

OBJECTIVE

To evaluate the effectiveness of routine ultrasound scanning in pregnancy by a meta-analysis of various outcome measures.

DESIGN

Meta-analysis of randomised controlled trials evaluating the effect of routine ultrasound scanning on perinatal mortality and morbidity. Live birth rate (that is, live births per pregnancy) is included as a measure of pregnancy outcome in addition to the conventional perinatal mortality.

SUBJECTS

15,935 pregnancies (7992 in which routine ultrasound scanning was used and 7943 controls with selective scanning) from four randomised controlled trials.

MAIN OUTCOME MEASURES

Perinatal mortality, live birth rate, rate of miscarriage, Apgar score < 7 at 1 minute, and number of induced labours.

RESULTS

The live birth rate was identical in both screening and control groups (odds ratio = 0.99; 95% confidence interval 0.88 to 1.12) although the perinatal mortality was significantly lower in the group who had routine ultrasonography (0.64, 0.43 to 0.97). Differences in perinatal morbidity between the two groups as measured by the proportion of newborn babies with Apgar score < 7 at 1 minute were not significant (1.05; 0.93 to 1.19).

CONCLUSION

Routine ultrasound scanning does not improve the outcome of pregnancy in terms of an increased number of live births or of reduced perinatal morbidity. Routine ultrasound scanning may be effective and useful as a screening for malformation. Its use for this purpose, however, should be made explicit and take into account the risk of false positive diagnosis in addition to ethical issues.

Judging fetal growth from body proportions at birth

Fetal growth velocity from 27 weeks until birth was calculated in 378 infants born after high risk pregnancies from at least three ultrasound measurements of estimated fetal weight and the weight at birth. Anthropometric measurements at birth (weight, head circumference, length, ponderal index and skinfolds), after correction for differences in gestational age, were significantly related to fetal growth velocity. The relation between fetal growth velocity and ponderal index was significant (correlation coefficient = 0.34, P < 0.001). However, the correlations between fetal growth velocity and each of the anthropometric measures disappeared when birth weight relative to gestational age was accounted for. This means that given the birth weight and the gestational age of a newborn infant, body proportions, e.g. ponderal index or skinfold thickness, do not contribute further to the judgment about fetal growth rate.