Pyramid of ANC care


Published on

Published in: Health & Medicine
  • Be the first to comment

  • Be the first to like this

No Downloads
Total views
On SlideShare
From Embeds
Number of Embeds
Embeds 0
No embeds

No notes for slide

Pyramid of ANC care

  1. 1. PRENATAL DIAGNOSISPrenat Diagn 2011; 31: 3–6.Published online in Wiley Online Library( DOI: 10.1002/pd.2685EDITORIALA model for a new pyramid of prenatal care basedon the 11 to 13 weeks’ assessmentKypros H. Nicolaides1,2 *1 Harris Birthright Research Centre of Fetal Medicine, King’s College Hospital, London, UK2 Department of Fetal Medicine, University College Hospital, London, UKOne century ago it was recognized that with the methodsand material at our disposal we were not making allthe progress possible toward solving many problemsof prenatal diagnosis and treatment (Ballantyne, 1901,1921). In order to achieve these objectives it was urgedthat a new means of investigation should be undertakenwhich had not yet been tried, at least not yet attemptedon a large scale and in a systematic fashion. This ledto the introduction of prenatal care which constituted amajor advance in the care of pregnant women and playeda pivotal role in the substantial reduction in maternal and Figure 1—Pyramid of prenatal care: past (left) and future (right)perinatal mortality achieved during the last century. In 1929, the Ministry of Health in the UK issued FETAL ANEUPLOIDIESa Memorandum on Antenatal Clinics recommendingthat women should first be seen at 16 weeks, then at We have learnt that about 90% of fetuses with major ane-24 and 28 weeks, fortnightly thereafter until 36 weeks uploidies can be identified by a combination of maternaland then weekly until delivery (Figure 1) (Ministry of age, fetal nuchal translucency (NT) thickness and mater-Health Report, 1929). No explicit rationale was offered nal serum-free ß-hCG and PAPP-A at 11 to 13 weeksfor either the timing or clinical content of visits, yet (Nicolaides, 2011). Improvement in the performance ofthese guidelines established the pattern of prenatal care first-trimester screening can be achieved by first carry-to be followed throughout the world until now. The ing out the biochemical test at 9 to 10 weeks and thehigh concentration of visits in the late third trimester ultrasound scan at 12 weeks and second, inclusion inimplies that most complications occur toward the end the ultrasound examination assessment of the nasal boneof pregnancy and most adverse outcomes cannot be and flow in the ductus venosus, hepatic artery and acrosspredicted from the first trimester. However, is this really the tricuspid valve. A similar performance of screeningthe case? Scientific advances in the last 20 years have can be achieved by examining the additional ultrasoundraised the hope that many pregnancy complications are markers in all cases and by a contingent policy in whichpotentially detectable from at least as early as the 12th first-stage combined screening classifies the patients asweek of gestation. It has become apparent that most high-, intermediate- and low-risk and the new markersmajor aneuploidies can be identified at 11 to 13 weeks’ are examined only in the intermediate-risk group whichgestation by a combination of maternal characteristics, is then reclassified as low- or high-risk.ultrasound findings and biochemical testing of maternalblood. It is also becoming increasingly apparent thatan integrated first hospital visit at 11 to 13 weeks FETAL STRUCTURAL ABNORMALITIEScombining data from maternal characteristics and historywith findings of biophysical and biochemical tests can We have learnt that at the 11 to 13 weeks’ scan itdefine the patient-specific risk for a wide spectrum is possible to diagnose or suspect the presence ofof pregnancy complications, including miscarriage and most major abnormalities, which are either lethal orfetal death, preterm delivery, preeclampsia, gestational associated with severe handicap, so that the parentsdiabetes, fetal growth restriction and macrosomia. can have the option of earlier and safer pregnancy termination. Major fetal abnormalities fall into essen- tially three groups in relation to whether they can be*Correspondence to: Prof. Kypros H. Nicolaides, Harris BirthrightResearch Centre for Fetal Medicine, King’s College Hospital, detected at the 11 to 13 weeks’ scan (Syngelaki et al.,Denmark Hill, London SE5 9RS, UK. 2011): first, those which are always detectable abnor-E-mail: malities, including body stalk anomaly, anencephaly,Copyright  2011 John Wiley & Sons, Ltd. Received: 30 November 2010 Revised: 5 December 2010 Accepted: 5 December 2010
  2. 2. 4 EDITORIALalobar holoprosencephaly, exomphalos, gastroschisis sonographic measurement of cervical length at 11 toand megacystis and second, undetectable abnormalities 13 weeks which is inversely related to the likelihoodbecause sonographic signs are only manifest during the for subsequent spontaneous early delivery (Greco et al.,second or third trimester of pregnancy, including some 2011). At present there are no other useful biophysical orbrain abnormalities, such as microcephaly, hypoplasia of biochemical markers of spontaneous early delivery (Betathe cerebellum or vermis, hydrocephalus and agenesis et al., 2011). Future research will determine whetherof the corpus callosum, achondroplasia, echogenic lung early intervention with such measures as prophylacticlesions, many renal anomalies and bowel obstruction. A use of progesterone or cervical cerclage will be effectivethird group includes abnormalities that are potentially in reducing spontaneous preterm delivery.detectable depending on first the objectives set for sucha scan and consequently the time allocated for the fetalexamination, the expertise of the sonographer and thequality of the equipment used and second, the pres- PREECLAMPSIAence of an easily detectable marker for an underlyingabnormality. Good examples of such markers in the firsttrimester include high NT in some fetuses with lethal We have learnt that in preeclampsia, which is a majorskeletal dysplasias (Khalil et al., 2011) and diaphrag- cause of maternal and perinatal morbidity and mor-matic hernia, high NT and abnormal flow in the ductus tality, both the degree of impaired placentation andvenosus and across the tricuspid valve in major cardiac the incidence of adverse fetal and maternal short-termdefects (Chelemen et al., 2011) and increase in brain and long-term consequences are inversely related tostem diameter with decrease in the diameter of the fourth the gestational age at the onset of the disease. Con-ventricle-cisterna magna complex in open spina bifida sequently, in screening for preeclampsia the condition(Lachmann et al., 2011). should be subdivided according to gestational age at delivery. Algorithms which combine maternal charac- teristics, mean arterial pressure, uterine artery Doppler MISCARRIAGE AND STILLBIRTH and biochemical tests at 11 to 13 weeks could potentially identify about 90, 80 and 60% of pregnancies that sub- sequently develop early (before 34 weeks), intermediateWe have learnt that the rates of miscarriage and stillbirth (34–37 weeks) and late (after 37 weeks) preeclampsia,after demonstration of a live fetus at 11 to 13 weeks are for a false positive rate of 5% (Akolekar et al., 2011b).about 1 and 0.4%, respectively. Increased risk for mis- Further investigations will determine whether in thecarriage and stillbirth are associated with certain mater- high-risk group pharmacological interventions, such asnal characteristics, including increasing maternal age low-dose aspirin, starting from the first trimester couldand maternal weight, previous miscarriage or stillbirth improve placentation and reduce the prevalence of theand African racial origin. Miscarriage and stillbirth are disease.also associated with abnormal results of first-trimesterscreening for aneuploidies, including increased fetal NTthickness, reversed a-wave in the fetal ductus veno-sus and low maternal serum PAPP-A (Akolekar et al.,2011a). At present there is no useful intervention for GESTATIONAL DIABETES MELLITUSavoidance of miscarriage and so the use of this algo-rithm in clinical practice is debatable (van Ravenswaaij We have learnt that in gestational diabetes mellituset al., 2011). In contrast, early identification of the group (GDM), which is associated with increased risk of mater-at high-risk for stillbirth could lead to a reduction of this nal and perinatal short-term and long-term complica-complication through closer monitoring of fetal growth tions, the performance of traditional screening at theand wellbeing and appropriate timing of delivery. end of the second trimester by a series of independent maternal characteristics is poor with a detection rate of about 60%, at a false positive rate of 30 to 40% (Waugh PRETERM DELIVERY et al., 2007). Algorithms which combine maternal char- acteristics and maternal serum levels of adiponectin, anWe have learnt that preterm birth is the leading cause adipocyte-derived polypeptide, and sex hormone bindingof perinatal death and handicap in children and the globulin, a liver-derived glycoprotein, at 11 to 13 weeksvast majority of mortality and morbidity relates to early could potentially identify about 75% of pregnancies thatdelivery before 34 weeks which occurs in about 2% subsequently develop GDM, for a false positive rate ofof singleton pregnancies. In two-thirds of the cases 20% (Nanda et al., 2011). Additionally, the diagnosis ofthis is due to spontaneous onset of labor or preterm GDM can be made in the first trimester by appropriateprelabor rupture of membranes and in the other one- adjustments to the traditional criteria of the oral glucosethird it is iatrogenic, mainly due to preeclampsia. The tolerance test (Plasencia et al., 2011). Future researchpatient-specific risk for spontaneous delivery before will determine whether in the high-risk group appro-34 weeks can be determined by an algorithm combining priate dietary advice and pharmacological interventions,maternal characteristics and obstetric history (Beta et al., such as metformin, could reduce the incidence of GDM2011). This a priori risk can be modified by the and associated fetal macrosomia.Copyright  2011 John Wiley & Sons, Ltd. Prenat Diagn 2011; 31: 3–6. DOI: 10.1002/pd
  3. 3. EDITORIAL 5 SMALL FOR GESTATIONAL AGE FETUSES patient-specific risk based on maternal age is modi- fied by the sonographic findings and results of bio- chemical testing both in the first and second trimestersWe have learnt that small for gestational age (SGA) of pregnancy. The new approach will adhere to thefetuses may be constitutionally small or growth restricted teachings of Hippocrates, that we should learn the pastdue to impaired placentation, genetic disease or and research the present to predict the future, and theenvironmental damage. In the growth-restricted group pronouncements of Galileo Galilei, that the language ofthe risks of perinatal death and handicap are substantially God is mathematics and that we should measure every-increased but these risks can be reduced if the condition thing that is measurable and make measurable every-is detected prenatally allowing appropriate monitoring thing that is not so.and delivery. Algorithms which combine maternal char- At 11 to 13 weeks the great majority of womenacteristics, mean arterial pressure, uterine artery Doppler would be classified as being at low-risk for pregnancyand the measurement of various placental products in complications and a small proportion of women wouldmaternal blood at 11 to 13 weeks could potentially be selected as being at high-risk (Figure 1). In theidentify, at a false positive rate of 10%, about 75% low-risk group the number of medical visits can beof pregnancies without preeclampsia delivering SGA substantially reduced to perhaps three. One visit atneonates before 37 weeks and 45% of those delivering at around 20 weeks will re-evaluate fetal anatomy andterm (Karagiannis et al., 2011). Since the proportion of growth and reassess risk for such complications asgrowth restricted to constitutional small fetuses is higher preeclampsia and preterm delivery. Another visit atin the preterm rather than term SGA, it is likely that the 37 weeks will assess maternal and fetal wellbeing andearly biophysical and biochemical markers identify the determine the best time and method of delivery and thisgrowth-restricted subgroup among the SGA. will be repeated at 41 weeks for the few that remain pregnant at this stage. The high-risk group can have close surveillance in specialist clinics both in terms of FETAL MACROSOMIA the investigations to be performed and the personnel involved in the provision of care. In each of these visits their risk will be reassessed and they will either remainWe have learnt that fetal macrosomia is associated with high-risk or they will become low-risk in which case theincreased risks for the mother, including cesarean section intensity of their care can be reduced.and trauma to the birth canal, and for the baby, including Future research will inevitably expand the number ofshoulder dystocia and consequent brachial plexus or conditions that can be identified in early pregnancy andfacial nerve injuries, fractures of the humerus or clavicle define genetic markers of disease that will improve theand birth asphyxia. Screening for macrosomia (birth accuracy of the a priori risk based on maternal charac-weight above the 90th centile for gestational age at teristics and medical history. Similarly, new biophysicaldelivery) by a combination of maternal characteristics and biochemical markers will be described that mayand obstetric history with fetal NT and maternal serum- replace some of the current ones and modify the valuefree ß-hCG and PAPP-A at 11 to 13 weeks could of others. As the years pass, it will become necessary topotentially identify, at a false positive rate of 10%, re-evaluate and improve the timing and content of eachabout 35% of women who deliver macrosomic neonates visit and the likelihood ratios for each test. Early iden-(Poon et al., 2011). Future research would identify tification of high-risk groups will also stimulate furthernew biophysical and biochemical markers which could research that will define the best protocol for their fol-improve the performance of screening and determine low up and development of strategies for the preventionthe extent to which early identification of the high-risk of disorders of pregnancy or their adverse can improve prenatal surveillance and prevention It is likely that the new challenge for improvement ofof macrosomia itself or the intrapartum complications pregnancy outcome will be met by inverting the pyramidrelated to the condition. of prenatal care (Figure 1) to introduce on a large scale and in a systematic fashion a new model of prenatal care which will be based on the results of a comprehensive THE NEW PYRAMID OF CARE assessment at 11 to 13 weeks.Early estimation of patient-specific risks for pregnancy REFERENCEScomplications would improve pregnancy outcome byshifting prenatal care from a series of routine visits Akolekar R, Bower S, Flack N, Bilardo CM, Nicolaides KH. 2011a. Predictionto a more individualized patient and disease-specific of miscarriage and stillbirth at 11–13 weeks and the contribution of chorionicapproach both in terms of the schedule and content of villus sampling. Prenat Diagn 31(1): 38–45.such visits. Each visit would have a predefined objective Akolekar R, Syngelaki A, Sarquis R, Zvanca M, Nicolaides KH. 2011b.and the findings will generate likelihood ratios that can Prediction of early, intermediate and late pre-eclampsia from maternal factors,be used to modify the individual patient and disease- biophysical and biochemical markers at 11–13 weeks. Prenat Diagn 31(1): 66–74.specific estimated risk from the initial assessment at Ballantyne JW. 1901. A plea for a pro-maternity hospital. BMJ 2101: 813–814.11 to 13 weeks. Such sequential screening is now well Ballantyne JW. 1921. The maternity hospital, with its antenatal and neo-natalestablished in screening for aneuploidies whereby the departments. BMJ 3137: 221–224.Copyright  2011 John Wiley & Sons, Ltd. Prenat Diagn 2011; 31: 3–6. DOI: 10.1002/pd
  4. 4. 6 EDITORIALBeta J, Akolekar R, Ventura W, Syngelaki A, Nicolaides KH. 2011. Prediction Nanda S, Savvidou M, Syngelaki A, Akolekar R, Nicolaides KH. 2011. of spontaneous preterm delivery from maternal factors, obstetric history Prediction of gestational diabetes mellitus by maternal factors and biomarkers and placental perfusion and function at 11–13 weeks. Prenat Diagn 31(1): at 11 to 13 weeks. Prenat Diagn 31(2): In press. 75–83. Nicolaides KH. 2011. Screening for fetal aneuploidies at 11 to 13 weeks. PrenatChelemen T, Syngelaki A, Maiz M, Allan L, Nicolaides KH. 2011. Contri- Diagn 31(1): 7–15. bution of ductus venosus Doppler in first trimester screening for major Plasencia W, Garcia R, Pereira S, Akolekar R, Nicolaides KH. 2011. Criteria cardiac defects. Fetal Diagn Ther. [Epub ahead of print]. DOI: for screening and diagnosis of gestational diabetes mellitus in the first- 10.1159/000322138. trimester of pregnancy. Fetal Diagn Ther. (In press).Greco E, Lange A, Ushakov F, Rodriguez Calvo J, Nicolaides KH. 2011. Poon LCY, Karagiannis G, Stratieva V, Syngelaki A, Nicolaides KH. 2011. Prediction of spontaneous preterm delivery from endocervical length at 11 First-trimester prediction of macrosomia. Fetal Diagn Ther. [Epub ahead of to 13 weeks. Prenat Diagn 31(1): 84–89. print]. DOI: 10.1159/000318565.Karagiannis G, Akolekar R, Sarquis R, Wright D, Nicolaides KH. 2011. Syngelaki A, Chelemen T, Dagklis T, Allan L, Nicolaides KH. 2011. Chal- Prediction of small for gestation neonates from biophysical and biochemical lenges in the diagnosis of fetal non-chromosomal abnormalities at markers at 11–13 weeks. Fetal Diagn Ther. [Epub ahead of print]. DOI: 11–13 weeks. Prenat Diagn 31(1): 90–102. 10.1159/000321694. van Ravenswaaij R, Tesselaar-van der Goot M, de Wolf S, van Leeuwen-Khalil A, Pajkrt E, Chitty LS. 2011. Early prenatal diagnosis of skeletal Spruijt M, Visser GHA, Schielen PCJI. 2011. First-trimester serum PAPP-A anomalies. Prenat Diagn 31(1): 115–124. and fβ-hCG concentrations and other maternal characteristics to establishLachmann R, Chaoui R, Moratalla J, Picciarelli G, Nicolaides KH. 2011. logistic regression-based predictive rules for adverse pregnancy outcome. Posterior brain in fetuses with spina bifida at 11 to 13 weeks. Prenat Diagn Prenat Diagn 31(1): 50–57. 31(1): 103–106. Waugh N, Scotland G, McNamee P, et al. 2007. Screening for type 2 diabetes:Ministry of Health Report. 1929. Memorandum on antenatal clinics: their literature review and economic modelling. Health Technol Assess 11(1–125). conduct and scope. His Majesty’s Stationery Office, 1930. London.Copyright  2011 John Wiley & Sons, Ltd. Prenat Diagn 2011; 31: 3–6. DOI: 10.1002/pd