Modalités de dépistage et de diagnostic du fœtus petit pour l’âge gestationnel

Assessing fetal growth in Africa: Application of the international WHO and INTERGROWTH-21st standards in a Beninese pregnancy cohort

BACKGROUND

Fetal growth restriction is a major complication of pregnancy and is associated with stillbirth, infant death and child morbidity. Ultrasound monitoring of pregnancy is becoming more common in Africa for fetal growth monitoring in clinical care and research, but many countries have no national growth charts. We evaluated the new international fetal growth standards from INTERGROWTH-21st and WHO in a cohort from southern Benin.

METHODS

Repeated ultrasound and clinical data were collected in women from the preconceptional RECIPAL cohort (241 women with singleton pregnancies, 964 ultrasounds). We modelled fetal biometric parameters including abdominal circumference (AC) and estimated fetal weight (EFW) and compared centiles to INTERGROWTH-21st and WHO standards, using the Bland and Altman method to assess agreement. For EFW, we used INTERGROWTH-21st standards based on their EFW formula (IG21st) as well as a recent update using Hadlock's EFW formula (IG21hl). Proportions of fetuses with measurements under the 10th percentile were compared.

RESULTS

Maternal malaria and anaemia prevalence was 43% and 69% respectively and 11% of women were primigravid. Overall, the centiles in the RECIPAL cohort were higher than that of INTERGROWTH-21st and closer to that of WHO. Consequently, the proportion of fetuses under 10th percentile thresholds was systematically lower when applying IG21st compared to WHO standards. At 27-31 weeks and 33-38 weeks, respectively, 7.4% and 5.6% of fetuses had EFW <10th percentile using IG21hl standards versus 10.7% and 11.6% using WHO standards.

CONCLUSION

Despite high anemia and malaria prevalence in the cohort, IG21st and WHO standards did not identify higher than expected proportions of fetuses under the 10th percentiles of ultrasound parameters or EFW. The proportions of fetuses under the 10th percentile threshold for IG21st charts were particularly low, raising questions about its use to identify growth-restricted fetuses in Africa.

Low Maternal DLK1 Levels at 26 Weeks Is Associated With Small for Gestational Age at Birth

Detecting SGA (small for gestational age) during pregnancy improves the fetal and neonatal prognosis. To date, there is no valid antenatal biomarker of SGA used in clinical practice. Maternal circulating DLK1 (delta-like non-canonical notch ligand 1) levels have been shown to be significantly lower in pregnant women at 36 weeks of gestation (WG) who delivered a SGA newborn than in controls. Data in the literature are contradictory on the association between maternal circulating DLK1 levels and placental vascular dysfunction. The objective was to determine if maternal DLK1 levels in the second trimester of pregnancy are predictive of SGA, and to assess whether the measurement of DLK1 levels in maternal blood could be a means to distinguish SGA with placental vascular dysfunction from that due to other causes. We conducted a nested cased-control study within the EDEN mother-child cohort. 193 SGA (birth weight < 10^th percentile) and 370 mother-child control (birth weight between the 25^th and 75^th percentile) matched pairs were identified in the EDEN cohort. Maternal circulating DLK1 levels at 26 WG were significantly lower for children born SGA than for controls (27.7 ± 8.7 ng/mL vs 30.4 ± 10.6 ng/mL, p = 0.001). Maternal blood DLK1 levels in the first quartile (DLK1 < 22.85 ng/mL) were associated with an odds ratio for SGA of 1.98 [1.15 - 3.37]. DLK1 was less predictive of SGA than ultrasound, with an area under the curve of 0.578. Maternal circulating DLK1 levels were not significantly different in cases of SGA with signs of placental vascular dysfunction (n = 63, 27.1 ± 9.2 ng/mL) than in those without placental dysfunction (n = 129, 28.0 ± 8.5 ng/mL, p = 0.53). The level of circulating DLK1 is reduced in the second trimester of pregnancy in cases of SGA at birth, independently of signs of placental vascular dysfunction. However, DLK1 alone cannot predict the risk of SGA.

Fetal growth restriction: underdiagnosed condition with non-optimal screening

BACKGROUND

Fetal Growth restriction (FGR) is the pathological failure of a fetus to reach its biologically determined growth potential. Detection of FGR fetuses is a universally agreed key objective of antenatal care. Antenatal detection of FGR has undeniable benefits, juggling between intensive fetal surveillance and optimized timing of delivery; it reduces adverse perinatal outcomes by up to four-fold. However, FGR is still widely underdiagnosed. We aimed to identify the prevalence of FGR diagnosis in our wards and study the impact of the 2013 published French guidelines on the detection rate of FGR. The secondary objective aimed to highlight the factors of suboptimal screening in the population of non-diagnosed FGR fetuses and emphasize the screening method that led to antenatal diagnosis of FGR.

MATERIALS AND METHODS

We conducted a retrospective study at a single tertiary maternity center in Lyon-France, the Femme Mère Enfant Hospital, including the exhaustive population of FGR born after 24 + 0 weeks of gestation from 1 January 2011 to 31 December 2017. FGR was defined combining the neonatal and antenatal consensus-based definitions for early and late FGR in absence of congenital anomalies, excluding small for gestational age fetuses. For all FGR fetuses, we compared the antenatal detection rate of FGR during 2011-2013 to 2015-2017, since the French guidelines were published in December 2013. When FGR fetuses underwent an antenatal diagnosis of FGR, we retrospectively collected the characteristics that led to the diagnosis. When fetuses were not diagnosed as FGR, we retrospectively reviewed the implementation of the recommended screening method, enabling to evaluate whether screening was optimal or not. Statistical analysis was performed in July 2018, and statistical significance was regarded as a p-value <.05.

RESULTS

Over the seven-year period, and among 31,052 newborns, 1020 (3.3%) infants were identified as FGR and met the inclusion criteria. The detection rate of FGR was similar before and after publication of the French Guidelines related to FGR in 2013. Indeed, 50.8% (201/395) FGR were diagnosed between 2011 and 2013 versus 52.6% (245/465) between 2015 and 2017 (p = .59). In the population of non-diagnosed FGR infants, screening was suboptimal in 80%. Symphysis-fundal height (SFH) was not measured in 10.7%, with no difference before and after 2014 (7.3 versus 11.8% p = .11). Ultrasound examination for fetal biometry had not been prescribed in spite of abnormal SFH in 47.7% of undiagnosed FGR infants. Diagnosis has been missed in 11.5% of infants because of misinterpretation of the estimated fetal weight's centile.

CONCLUSION

FGR is widely underdiagnosed. However, the limited performances can partially be explained by the regular misuse of screening method in clinical practice. Despite the systematic third trimester ultrasound screening, the detection rate of FGR was similar to the one reported in the medical literature. The timing of routine third trimester ultrasound in low-risk women may be rethought.

Standardized healthcare pathway in intrauterine growth restriction and minimum evidence-based care

INTRODUCTION

Fetal growth restricted fetuses are less likely to receive evidence-based care; a previous work demonstrated an improvement in neonatal prognosis when fetuses with intrauterine growth restriction (IUGR) received minimum evidence based-care.

OBJECTIVE

The objective of the study was to evaluate the impact of a standardized healthcare pathway on the implementation of the recommended clinical practice in the antenatal management of IUGR fetuses, in comparison to a traditional pathway. The quality of the implementation of practice has been defined whether or not minimum evidence-based care (MEC), defined according to the recommendations of the French college of gynecologists and obstetricians (CNGOF), has been implemented.

STUDY DESIGN

From a historical cohort of 31,052 children, born at the Femme Mère Enfant Hospital (Lyon, France) between January 1st, 2011 and December 31st, 2017, we selected the population of IUGR fetuses. We compared the rate of MEC between the IUGR fetuses followed-up in the traditional healthcare pathway versus the IUGR fetuses followed-up in a standardized healthcare pathway between 2015 and 2017.

RESULTS

A total of 245 IUGR were tracked between 2015 and 2017. Over this period, 120 fetuses were followed within the traditional pathway and 125 within the IUGR pathway. The standardized pathway resulted in a higher rate of MEC (86,4%) when compared to IUGR fetuses followed-up in the traditional pathway (27,5% (OR* 20 (95 % CI 10.0-39.7). Among early-onset IUGR: 31 % received MEC in the traditional pathway versus 83 % in the standardized pathway (p<0.001). Among late-onset IUGR: 22 % received MEC in the traditional pathway versus 92 % in the standardized pathway (p<0.001). The provided care in the standardized pathway resulted in an increase of complete antenatal corticosteroid therapy (92,8 %) when compared to the traditional pathway (50.0 %; p<0.001) and a reduction of the rate of caesarean sections before labor for non-reassuring fetal heart rate (15 %) when compared to the traditional pathway (41.3 % p=0.007).

CONCLUSION

The standardized pathway improves the implementation of the local recommendations in the management of early- and late-onset IUGR. This study is the first to suggest a standardized care pathway in prenatal medicine. A medico-economic study could estimate the health care savings that such a pathway would provide by allowing a medical management in accordance with the recommendations.

Antenatal detection of fetal growth restriction and risk of stillbirth: population-based case-control study

OBJECTIVES

Antenatal surveillance of intrauterine growth aims to detect growth-restricted fetuses (FGR), which face increased risk of stillbirth. Improving their detection could be an effective strategy for prevention of stillbirth. The French REPERE study was conducted to estimate the association between antenatal detection of FGR and risk of stillbirth.

METHODS

REPERE is a case-control study performed in three French districts with a combined total of approximately 30 000 births annually. Cases were singleton small-for-gestational-age (SGA) stillbirths ≥ 24 weeks' gestation and without severe congenital anomaly, between 2012 and 2014, identified using a population-based stillbirth registry; controls were live births fulfilling the same inclusion criteria over a 9-week period from 7 April to 8 June 2014. Data were extracted by trained investigators from medical records and ultrasound reports. SGA was defined as birth weight < 10^th percentile of French customized standards. FGR was defined by the presence of at least one of seven predefined parameters (suspected FGR mentioned in medical records or in ultrasound report, suspected faltering growth mentioned in an ultrasound report, documented abdominal circumference or estimated fetal weight < 10^th percentile, referral for additional ultrasound examination to monitor growth or abnormal umbilical artery Doppler). We used logistic regression to estimate crude and adjusted odds ratios (ORs) for the association between detection of FGR and risk of stillbirth. Included covariables were parity, maternal medical history, vascular complications during pregnancy and birth-weight percentile, which are known to be associated with risk of detection of FGR and of stillbirth.

RESULTS

During the study period, there were 92 182 births ≥ 22 weeks' gestation, including 669 stillbirths, of which 79 were singleton SGA stillbirths ≥ 24 weeks and without severe congenital anomaly. Of these cases, 44.3% (35/79) had FGR detected, compared with a detection rate of 36.2% in controls (154/426). The crude OR expressing the association between detection of FGR and risk of stillbirth was 1.4 (95% CI, 0.9-2.3) and the OR adjusted for parity, presence of risk factors for FGR, presence of vascular disorder and birth-weight percentile was 0.6 (95% CI, 0.3-1.0). Among deliveries ≥ 28 weeks, detection rates were 38.3% vs 36.0% for cases and controls, with an adjusted OR of 0.5 (95% CI, 0.2-1.0).

CONCLUSION

Antenatal detection of FGR was protective against stillbirth, but over 40% of stillbirths among SGA fetuses occurred despite detection of FGR, pointing to the need to improve management following detection. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

[Evaluation of a measurement tool with real-time display of the standard value for fetal biometrics]

OBJECTIVES

Most of the ultrasound machines include a tool allowing real-time display of the standard value of the biometric measurement being taken. Our hypothesis was that this tool influences the sonographer as measurements are taken, by inducing a normalization, thus a tendency towards the 50th percentile. The objective of this study was to evaluate the impact of a real-time display of the standard value in prenatal ultrasound screening.

METHODS

We conducted an observational, prospective, controlled and open study including all patients who underwent a prenatal ultrasound scan in the 2nd or 3rd trimester at the University Hospitals in Strasbourg between December 2017 and June 2018. Exclusion criteria were the presence of a fetal morphological abnormality or a karyotypic abnormality. The tool being tested was the real-time display on screen of the gestational age, of which the measurement corresponds to the 50th percentile. The measurements were retrospectively transformed into Z-scores. The main end-point was to compare the distribution of Z-scores between the groups.

RESULTS

We included 3551 ultrasound examinations: 696 performed with the tool and 2796 performed without. Fifty-nine scans were excluded due to morphological abnormalities. There was no statistically significant difference between the Z-scores distributions of measurements performed with or without the tool, regardless of the parameter studied. There was also no difference in the detection of pathological measurements: below the 10th percentile or above the 90th percentile.

CONCLUSION

The use of such a tool does not seem to be detrimental to biometric screening, but on the other hand does not seem useful either.

Impact of customized growth curves on screening for small for gestational age twins

OBJECTIVE

The choice of a growth curve determines the screening for small-for-gestational-age (SGA) fetuses and little data is available on SGA twins. Our aim was to evaluate small-for-gestational-age (SGA) detection rate in twin pregnancies and assess whether the use of a customized curve allowed better identification of SGA fetuses.

STUDY DESIGN

Retrospective study including all twins between 2010 and 2013. Two groups were formed: the SGA and the non-SGA group. Four curves were compared: Hadlock's curve, a customized curve, EPOPé M0 and EPOPé M1. We defined a composite neonatal complication criterion (transfer to intensive care unit, respiratory distress and death).

RESULT

472 fetuses were included with a 34.3% prevalence of SGA. Hadlock's curve showed better sensitivity for the detection of SGA <10th percentile (67.3% vs. 63%, 59.9% and 57.4% respectively). Diagnostic Odd Ratio were comparable for the detection of SGA. For the composite variable, there was a significant difference between the 2 groups using a customized curve adjusted for fetal sex (EPOPé M1).

CONCLUSION

The EPOPé (M0 and M1) and customized curves do not improve screening for SGA infants below the 10th percentile. The reduced effectiveness of customized curves can be related to the greater impact of placentation or cord insertion on the potential for fetal growth.

Variation in the definition of intrauterine growth restriction in routine antenatal care: a physician survey among gynecologists in Northwest Germany

OBJECTIVE

To assess how intrauterine growth restriction (IUGR) is defined by gynecologists in routine practice.

MATERIALS AND METHODS

We surveyed primary care gynecologists in Bremen and Lower Saxony, Northwest Germany, between January and July 2014. Descriptive statistics were used to analyze the data; consensus was considered as 90% agreement among the respondents. Multiple logistic regression models were performed for the associations between respondents' background characteristics and choice of the small for gestational age (SGA) cutoff values.

RESULTS

Overall, 185 primary care gynecologists participated in the survey. Consensus was only observed in two items: (1) an accurate determination of gestational age (91%) and (2) repeated measurement of the abdominal circumference (91%). Umbilical artery Doppler (76%) and repeated ultrasonography (76%) were the most frequently used methods to confirm suspected IUGR diagnoses, but different responses prevailed. Notably, only 46% of the respondents opted for the 10th percentile of estimated fetal weight as a cutoff for SGA classification, which is the internationally recommended value.

CONCLUSIONS

The results of this survey indicate considerable practice variation regarding detection and management of IUGR pregnancies. There is a need for better agreement in terminology and definition of core aspects of IUGR in antenatal care.

[Is the stomach a main landmark on the abdominal circumference? Audit of 3 operators]

OBJECTIVES

The fetal weight estimation depends largely on the accuracy of abdominal circumference. The quality criteria are standardized to minimize variability and include visualization of the stomach. The objective of this study is to investigate the presence or absence of the stomach on the abdominal circumference for 3 different operators.

MATERIAL AND METHODS

We conducted re-reading of 204 ultrasound images in the second and third trimester of pregnancy, performed by three operators, at the maternity Port Royal in Paris in 2013. On these images, the presence of the stomach was sought and other quality criteria were verified.

RESULTS

Among the 204 images, 166 included the stomach (81%). When studying for each of the three operators, there were 79%, 72% and 98% of the stomach into the abdominal circumference, a significant difference between operators (P=0.0029). Regarding the secondary criteria, the quality criteria found most often were the calipers and well placed ellipse (89%).

CONCLUSION

According to the previous studies, the stomach seems to be a reference to search. Our study shows variability depending on the different operators. If a hierarchy of quality criteria is to be considered, the stomach does not seem to be the first criterion to search.

Fetal growth restriction and intra-uterine growth restriction: guidelines for clinical practice from the French College of Gynaecologists and Obstetricians

Small for gestational age (SGA) is defined by weight (in utero estimated fetal weight or birth weight) below the 10th percentile (professional consensus). Severe SGA is SGA below the third percentile (professional consensus). Fetal growth restriction (FGR) or intra-uterine growth restriction (IUGR) usually correspond with SGA associated with evidence indicating abnormal growth (with or without abnormal uterine and/or umbilical Doppler): arrest of growth or a shift in its rate measured longitudinally (at least two measurements, 3 weeks apart) (professional consensus). More rarely, they may correspond with inadequate growth, with weight near the 10th percentile without being SGA (LE2). Birthweight curves are not appropriate for the identification of SGA at early gestational ages because of the disorders associated with preterm delivery. In utero curves represent physiological growth more reliably (LE2). In diagnostic (or reference) ultrasound, the use of growth curves adjusted for maternal height and weight, parity and fetal sex is recommended (professional consensus). In screening, the use of adjusted curves must be assessed in pilot regions to determine the schedule for their subsequent introduction at national level. This choice is based on evidence of feasibility and the absence of any proven benefits for individualized curves for perinatal health in the general population (professional consensus). Children born with FGR or SGA have a higher risk of minor cognitive deficits, school problems and metabolic syndrome in adulthood. The role of preterm delivery in these complications is linked. The measurement of fundal height remains relevant to screening after 22 weeks of gestation (Grade C). The biometric ultrasound indicators recommended are: head circumference (HC), abdominal circumference (AC) and femur length (FL) (professional consensus). They allow calculation of estimated fetal weight (EFW), which, with AC, is the most relevant indicator for screening. Hadlock's EFW formula with three indicators (HC, AC and FL) should ideally be used (Grade B). The ultrasound report must specify the percentile of the EFW (Grade C). Verification of the date of conception is essential. It is based on the crown-rump length between 11 and 14 weeks of gestation (Grade A). The HC, AC and FL measurements must be related to the appropriate reference curves (professional consensus); those modelled from College Francais d'Echographie Fetale data are recommended because they are multicentere French curves (professional consensus). Whether or not a work-up should be performed and its content depend on the context (gestational age, severity of biometric abnormalities, other ultrasound data, parents' wishes, etc.) (professional consensus). Such a work-up only makes sense if it might modify pregnancy management and, in particular, if it has the potential to reduce perinatal and long-term morbidity and mortality (professional consensus). The use of umbilical artery Doppler velocimetry is associated with better newborn health status in populations at risk, especially in those with FGR (Grade A). This Doppler examination must be the first-line tool for surveillance of fetuses with SGA and FGR (professional consensus). A course of corticosteroids is recommended for women with an FGR fetus, and for whom delivery before 34 weeks of gestation is envisaged (Grade C). Magnesium sulphate should be prescribed for preterm deliveries before 32-33 weeks of gestation (Grade A). The same management should apply for preterm FGR deliveries (Grade C). In cases of FGR, fetal growth must be monitored at intervals of no less than 2 weeks, and ideally 3 weeks (professional consensus). Referral to a Level IIb or III maternity ward must be proposed in cases of EFW <1500g, potential birth before 32-34 weeks of gestation (absent or reversed umbilical end-diastolic flow, abnormal venous Doppler) or a fetal disease associated with any of these (professional consensus). Systematic caesarean deliveries for FGR are not recommended (Grade C). In cases of vaginal delivery, fetal heart rate must be monitored continuously during labour, and any delay before intervention must be faster than in low-risk situations (professional consensus). Regional anaesthesia is preferred in trials of vaginal delivery, as in planned caesareans. Morbidity and mortality are higher in SGA newborns than in normal-weight newborns of the same gestational age (LE3). The risk of neonatal mortality is two to four times higher in SGA newborns than in non-SGA preterm and full-term infants (LE2). Initial management of an SGA newborn includes combatting hypothermia by maintaining the heat chain (survival blanket), ventilation with a pressure-controlled insufflator, if necessary, and close monitoring of capillary blood glucose (professional consensus). Testing for antiphospholipids (anticardiolipin, circulating anticoagulant, anti-beta2-GP1) is recommended in women with previous severe FGR (below third percentile) that led to birth before 34 weeks of gestation (professional consensus). It is recommended that aspirin should be prescribed to women with a history of pre-eclampsia before 34 weeks of gestation, and/or FGR below the fifth percentile with a probable vascular origin (professional consensus). Aspirin must be taken in the evening or at least 8h after awakening (Grade B), before 16 weeks of gestation, at a dose of 100-160mg/day (Grade A).