Abstract The aim of the present study was to evaluate the efficacy of the first trimester screening for Down syndrome (DS) in an unselected low-risk Finnish population. The study involved 4,617 women who attended screening between the 8th and 14th weeks of pregnancy in 1998-2000. They gave a blood sample for the measurement of pregnancy associated plasma protein A (PAPP-A) and free beta human chorionic gonadotrophin (β-hCG). Of these women, 3,178 also had an ultrasound examination for the measurement of fetal nuchal translucency (NT). The risk figure for every screened woman was calculated using a computerized risk figure program. The risk 1 in 250 was used as a cut-off. The subgroup of screen positives comprised 5.8% of the study group. There were 16 DS cases. The combined method (maternal age, NT and the biochemical markers) detected 77% of the affected pregnancies. NT combined with maternal age gave a detection rate of 69%. Serum markers without NT combined with maternal age found 75% of the Down's. In 49 consecutive singleton in-vitro-fertilization pregnancies, the β-hCG value was more often elevated compared to spontaneous pregnancies, increasing the false positive rate. In 67 twin pregnancies, the serum marker levels were approximately double those in singletons. Smoking reduced PAPP-A by 20% making the smokers more likely to get a positive screening result. To determine the impact of the screening on the live born incidence of DS, two historical populations were compared. The first group was screened by second trimester serum samples (β-hCG and AFP) and the second group by first trimester ultrasound examination. When detection rates were at the same level, the second trimester screening reduced the number of live born Down's children more effectively. In conclusion, the first trimester combined method (maternal age, NT, β-hCG and PAPP-A) for Down syndrome screening is efficient in an unselected low risk population. The biochemical screening is not recommended in IVF-pregnancies.

Objetivo: analisar o resultado das gestações e pós-natal dos fetos com translucência nucal (TN) aumentada. Método: Duzentos e setenta e cinco fetos com TN aumentada foram avaliados no setor de Medicina Fetal da Clínica Obstétrica do HC-FMUSP, com análise do cariótipo, ultra-sonografia seriada, ecocardiografias fetal e pós-natal e avaliação clinica genética pós-natal. Resultados: 14,2% apresentaram cariótipos alterados e 85,8% normais. A ultra-sonografia morfológica esteve alterada em 73,1% dos casos com cariótipo anormal e em 24,7% dos normais, destes, um terço apresentou malformações estruturais maiores, sendo 35,7% cardíacas. Resultados gestacionais adversos, como abortamento, óbitos intra-útero e neonatal ocorreram em 76,5% dos fetos com anomalias cromossômicas e em 10,2% com cariótipos normais. A avaliação pós-natal foi realizada em 72,7% das crianças, mostrando-se alterada em 14,8% dos casos. A freqüência de criança viva e saudável diminuiu com a medida da TN, que variou de 37,5%, nos casos com cariótipos normais, a 18,8% com cariótipos desconhecidos, quando a TN foi igual ou maior que 4,5 mm. Conclusão: Quanto maior a TN maior o risco de anomalias cromossômicas e, nos casos com cariótipos normais, maior a freqüência de malformações estruturais, em especial defeitos cardíacos, resultados gestacionais adversos e alterações à avaliação pós-natal / The aim of this study was to evaluate pregnancy and postnatal outcomes in fetuses with increased nuchal translucency thickness (NT). Two hundred seventy five fetuses with increased NT were examined with karyotyping analysys, serial ultrasound scans, ecocardiography and postnatal clinical and genetic evaluation at the Fetal Medicine Unit - Departament of Obstetrics - São Paulo University. The karyotype was abnormal in 14.2% of the cases and normal in 85.8%. At the anomaly scan, 73.1% of the abnormal karyotype and 24.7% of the normal fetuses presented structural abnormalities, one third of these were major malformations with 35.7% of cardiac defects. Adverse pregnancy outcome as miscarriages, intrauterine and neonatal deaths occurred in 76.5% of the abnormal karyotype group and in 10.2% of the normal. 72.7% of the infants with normal karyotype had postnatal examination with 14,8% presenting abnormalities. The chances of having a live and healthy child decreased with increased NT thickness. For NT above 4.5mm this varied from 18.8%, for an unknown karyotype result, to 37.5% for a normal karyotype. The chances of abnormal karyotype increased with NT thickness. In addition, when the karyotype was normal, the frequency of fetal malformations, specially heart defects, adverse pregnancy outcome and postnatal abnormalities increased with NT thickness

Objetivo: analisar o resultado das gestações e pós-natal dos fetos com translucência nucal (TN) aumentada. Método: Duzentos e setenta e cinco fetos com TN aumentada foram avaliados no setor de Medicina Fetal da Clínica Obstétrica do HC-FMUSP, com análise do cariótipo, ultra-sonografia seriada, ecocardiografias fetal e pós-natal e avaliação clinica genética pós-natal. Resultados: 14,2% apresentaram cariótipos alterados e 85,8% normais. A ultra-sonografia morfológica esteve alterada em 73,1% dos casos com cariótipo anormal e em 24,7% dos normais, destes, um terço apresentou malformações estruturais maiores, sendo 35,7% cardíacas. Resultados gestacionais adversos, como abortamento, óbitos intra-útero e neonatal ocorreram em 76,5% dos fetos com anomalias cromossômicas e em 10,2% com cariótipos normais. A avaliação pós-natal foi realizada em 72,7% das crianças, mostrando-se alterada em 14,8% dos casos. A freqüência de criança viva e saudável diminuiu com a medida da TN, que variou de 37,5%, nos casos com cariótipos normais, a 18,8% com cariótipos desconhecidos, quando a TN foi igual ou maior que 4,5 mm. Conclusão: Quanto maior a TN maior o risco de anomalias cromossômicas e, nos casos com cariótipos normais, maior a freqüência de malformações estruturais, em especial defeitos cardíacos, resultados gestacionais adversos e alterações à avaliação pós-natal / The aim of this study was to evaluate pregnancy and postnatal outcomes in fetuses with increased nuchal translucency thickness (NT). Two hundred seventy five fetuses with increased NT were examined with karyotyping analysys, serial ultrasound scans, ecocardiography and postnatal clinical and genetic evaluation at the Fetal Medicine Unit - Departament of Obstetrics - São Paulo University. The karyotype was abnormal in 14.2% of the cases and normal in 85.8%. At the anomaly scan, 73.1% of the abnormal karyotype and 24.7% of the normal fetuses presented structural abnormalities, one third of these were major malformations with 35.7% of cardiac defects. Adverse pregnancy outcome as miscarriages, intrauterine and neonatal deaths occurred in 76.5% of the abnormal karyotype group and in 10.2% of the normal. 72.7% of the infants with normal karyotype had postnatal examination with 14,8% presenting abnormalities. The chances of having a live and healthy child decreased with increased NT thickness. For NT above 4.5mm this varied from 18.8%, for an unknown karyotype result, to 37.5% for a normal karyotype. The chances of abnormal karyotype increased with NT thickness. In addition, when the karyotype was normal, the frequency of fetal malformations, specially heart defects, adverse pregnancy outcome and postnatal abnormalities increased with NT thickness

Le placenta humain est un organe indispensable au maintien de la grossesse et au développement foetal. Son unité structurale et fonctionnelle est la villosité choriale constituée principalement de trophoblastes qui se différencient selon la voie villeuse endocrine ou extravilleuse invasive. Ces deux populations trophoblastiques sécrètent de l'hormone chorionique gonadotrope humaine (hCG), hormone indispensable à la grossesse. C'est une glycoprotéine constituée de deux sous-unités: la sous-unité alpha commune avec la LH, FSH et la TSH et la sous-unité beta, spécifique à chaque hormone, codée par un cluster de gênes regroupés en type I (gêne beta 7) et type II (gênes beta 3, 5 et 8). L'hCG est sécrétée dans le compartiment maternel où elle joue un rôle endocrine essentiel au maintien de la grossesse en stimulant la production de progestérone par l'ovaire. L'hCG joue également un rôle localement en stimulant la différenciation de chaque type de trophoblaste. Elle présente, dans le sang maternel, un pic de sécrétion à 10-12 semaines d'aménorrhée (SA), période ou le statut oxydatif placentaire change. En effet, les bouchons trophoblastiques obstruant la lumière des artères spiralées utérines se délitent à cette période, permettant l'entrée progressive du sang maternel dans la chambre intervilleuse. La pression en oxygène augmente de 18 mm/Hg (8-9 SA, 1er trimestre précoce) à 60 mm/Hg (12-14 SA, 1er trimestre tardif). Dans mon travail de thèse, j'ai cherché à mettre en évidence in situ et in vitro l'impact de ce changement de statut oxydatif sur la différenciation des trophoblastes villeux du 1er trimestre, et plus particulièrement sur l'expression des hCG beta de type I et de type II. J'ai ainsi mis en évidence que les trophoblastes villeux mononucléés du 1er trimestre précoce sécrétaient plus d'hCG beta de type I et II, fusionnaient plus rapidement et exprimaient un panel de facteurs de transcription différents par rapport aux trophoblastes villeux du 1er trimestre tardif. Dans un deuxième temps, j'ai comparé in vitro l'expression et la régulation des deux types d'hCG beta entre les trophoblastes villeux et extravilleux. J'ai montré que: 1) les trophoblastes villeux expriment plus d'hCG beta de type I et II que les trophoblastes extravilleux, 2) dans les deux cas l'hCG beta de type II est majoritaire et 3) PPAR gamma régule de façon opposée ces deux types d'hCG entre les trophoblastes villeux et extravilleux. Enfin j'ai mis en évidence que l'expression de ces deux types d'hCG était dérégulée dans la pré-éclampsie et le RCIU. L'étude des mécanismes impliqués dans la régulation des gênes codants pour l'hCG représente un enjeu important pour la compréhension de la différenciation du trophoblaste humain, du développement précoce du placenta et des pathologies de la grossesse. / The human placenta is an essential organ to maintain pregnancy and for foetal growth. Its structural and functional unit is the chorionic villous, which is mainly composed of cytotrophoblasts that follow two differentiation pathways: the endocrine villous and the invasive extravillous trophoblasts. These two trophoblastic subtypes secrete the human chorionic gonadotropin hormone (hCG), an essential hormone for trophoblast differentiation, placental development and pregnancy. hCG is a glycoprotein composed of two subunits: the alpha subunit, which is common to LH, FSH and TSH, and the beta subunit that confers hormone specificity. A gene cluster encodes the beta subunit, type I (CGB7) and type II (CGB3, 5 and 8), that code for two different proteins. hCG is detected in the maternal blood from the first week of pregnancy, with a peak level at 10-12 weeks of gestation (WG). During the first trimester the oxygen concentration in the intervillous space changes from about 2% (prior to 10 WG) to approximately 6-8% (after 12 WG) due to development of blood flow to the placenta. During my PhD work, I studied in situ and in vitro the impact of these different environments during the first trimester on villous cytotrophoblast differentiation, and more specifically on the type I and type II beta hCG gene expression. I showed that type I and type II beta hCG are more expressed in early first trimester cytotrophoblasts and that these cells exibit more fusion features and express a different panel of transcription factors compare to cells from late first trimester. In the second part of my work, I compared the expression and the regulation in vitro of the two types of beta hCG between villous and extravillous cytotrophoblasts. I demonstrated: 1) villous trophoblast express more type I and type II beta hCG compared to the extravillous trophoblast, 2) in both case type II hCG beta is the major form of beta hCG and 3) PPAR gamma differentially regulates type I and type II beta hCG expression in villous and extravillous trophoblasts. Lastly I showed that the expression of type I and type II beta hCG is deregulated in pre-eclampsia and FGR. The study of the mechanisms involved in hCG regulation represents an important issue for the understanding of human trophoblast differenciation and pregnancy pathophysiology.

No description available.

This study sought to determine if ANC and PMTCT services are utilized within the first trimester of pregnancy by the women in East Ekurhuleni sub-district. Quantitative descriptive research was conducted on 390 eligible pregnant women and data collection was done using structured questionnaires. The results indicated that women start ANC late despite their knowledge of first trimester as the best time to start ANC. Actions that would motivate them to start ANC early were explored and barriers were identified. / Health Studies / MA (Public Health)

La présente thèse par articles aborde différentes facettes du dépistage prénatal de certaines aneuploïdies au premier trimestre de la grossesse. L’introduction retrace l’historique du dépistage prénatal et énonce les différents marqueurs biochimiques et échographiques associés aux aneuploïdies. La première publication démontre que le tabagisme maternel abaisse significativement les niveaux sanguins maternels de PAPP-A et de la fraction libre de la β-hCG et augmente significativement la clarté nucale, confirmant la nécessité de contrôler cette co-variable dans le calcul de risque final, du moins pour la trisomie 18. Le deuxième article identifie des seuils de clarté nucale au-delà desquels la biochimie génétique n’apporte aucune valeur additionnelle au dépistage prénatal de la trisomie 21 et de la trisomie 18. Pour les fœtus avec clarté nucale supérieure aux seuils établis, un diagnostic prénatal intrusif devrait être offert sans délai. Le troisième et dernier article porte sur la première détermination des niveaux plasmatiques maternels de la protéine FLRG (follistatin-related gene) au premier trimestre de grossesse et sur son rôle potentiel à titre de marqueur biochimique dans le dépistage prénatal de la trisomie 21. Bien que détectables, les niveaux plasmatiques maternels de FLRG ne sont pas significativement altérés en présence de fœtus avec syndrome de Down. Dans la discussion générale, les trois articles sont abordés sous un angle plus spécifique au Québec. Des données complémentaires et originales y sont présentées. Une discussion sur l’évolution future du dépistage prénatal est entamée et des axes de recherche sont proposés. / In this thesis by articles, we explore different facets of first trimester prenatal screening of aneuploidy. Introduction retraces the origin of prenatal screening and enunciates current biochemical and ultrasound markers associated with aneuploidy. In the first article, impact of maternal smoking on first-trimester prenatal screening results is assessed for Down syndrome and trisomy 18. Both maternal blood levels of PAPP-A and free β-hCG are significantly decreased by maternal smoking while fetal nuchal translucency (NT) thickness is significantly increased. Without adjustment, this results in an increase of false positives, at least for trisomy 18. Based on these results, adjustment for smoking should be mandatory in first-trimester prenatal screening. In the second article, we identify NT threshold values above which biochemical screening provides no additional benefit. In pregnancies in which NT is above the proposed upper cut-offs, invasive prenatal screening should be offered without undue delay. In the third and last article, maternal plasma levels of follistatin- related gene protein (FLRG) are determined for the first time in first trimester of pregnancy. Its potential role as a new marker for Down syndrome is assessed. Although FLRG can be successfully detected in maternal plasma, its levels are not significantly altered by the presence of Down syndrome fetuses. In the general discussion, articles are mainly addressed under a Quebec standpoint. Additional and complementary original data are presented and different clinical research avenues are proposed.

La présente thèse par articles aborde différentes facettes du dépistage prénatal de certaines aneuploïdies au premier trimestre de la grossesse. L’introduction retrace l’historique du dépistage prénatal et énonce les différents marqueurs biochimiques et échographiques associés aux aneuploïdies. La première publication démontre que le tabagisme maternel abaisse significativement les niveaux sanguins maternels de PAPP-A et de la fraction libre de la β-hCG et augmente significativement la clarté nucale, confirmant la nécessité de contrôler cette co-variable dans le calcul de risque final, du moins pour la trisomie 18. Le deuxième article identifie des seuils de clarté nucale au-delà desquels la biochimie génétique n’apporte aucune valeur additionnelle au dépistage prénatal de la trisomie 21 et de la trisomie 18. Pour les fœtus avec clarté nucale supérieure aux seuils établis, un diagnostic prénatal intrusif devrait être offert sans délai. Le troisième et dernier article porte sur la première détermination des niveaux plasmatiques maternels de la protéine FLRG (follistatin-related gene) au premier trimestre de grossesse et sur son rôle potentiel à titre de marqueur biochimique dans le dépistage prénatal de la trisomie 21. Bien que détectables, les niveaux plasmatiques maternels de FLRG ne sont pas significativement altérés en présence de fœtus avec syndrome de Down. Dans la discussion générale, les trois articles sont abordés sous un angle plus spécifique au Québec. Des données complémentaires et originales y sont présentées. Une discussion sur l’évolution future du dépistage prénatal est entamée et des axes de recherche sont proposés. / In this thesis by articles, we explore different facets of first trimester prenatal screening of aneuploidy. Introduction retraces the origin of prenatal screening and enunciates current biochemical and ultrasound markers associated with aneuploidy. In the first article, impact of maternal smoking on first-trimester prenatal screening results is assessed for Down syndrome and trisomy 18. Both maternal blood levels of PAPP-A and free β-hCG are significantly decreased by maternal smoking while fetal nuchal translucency (NT) thickness is significantly increased. Without adjustment, this results in an increase of false positives, at least for trisomy 18. Based on these results, adjustment for smoking should be mandatory in first-trimester prenatal screening. In the second article, we identify NT threshold values above which biochemical screening provides no additional benefit. In pregnancies in which NT is above the proposed upper cut-offs, invasive prenatal screening should be offered without undue delay. In the third and last article, maternal plasma levels of follistatin- related gene protein (FLRG) are determined for the first time in first trimester of pregnancy. Its potential role as a new marker for Down syndrome is assessed. Although FLRG can be successfully detected in maternal plasma, its levels are not significantly altered by the presence of Down syndrome fetuses. In the general discussion, articles are mainly addressed under a Quebec standpoint. Additional and complementary original data are presented and different clinical research avenues are proposed.

This study sought to determine if ANC and PMTCT services are utilized within the first trimester of pregnancy by the women in East Ekurhuleni sub-district. Quantitative descriptive research was conducted on 390 eligible pregnant women and data collection was done using structured questionnaires. The results indicated that women start ANC late despite their knowledge of first trimester as the best time to start ANC. Actions that would motivate them to start ANC early were explored and barriers were identified. / Health Studies / M.A. (Public Health)