PRENATAL DIAGNOSIS,VOL.
1 1,621-624 (199 1)
:FIRST-TRIMESTER SCREENING FOR FETAL CHROMOSOMAL ABNORMALITIES. PRELIMINARY RESULTS I. M. M. VAN LITH, FOR THE DUTCH WORKING PARTY ON PRENATAL DIAGNOSIS* Department of Obstetrics and Gynaecology, University Hospital Groningen, Oostersingel59, 9713 EZ Groningen. The Netherlands
SUMMARY We have started a multicentre trial to study the possibilities of first-trimester maternal serum screening for fetal chromosomal abnormalities. Maternal blood samples were obtained befotre 13 weeks of gestation. We present the preliminary results of the first 950 patients on alpha-fetoprotein(AFP). Results on cancer antigen 125 (CA 125) in Down’s syndrome and nornial pregnancies are also presented. We conclude that the results on AFP are promising and that CA 125 might be predictive for fetal Down’s syndrome. KEY WORDS
First trimester Down’s syndrome Autosomal trisomy Alpha-fetoprotein CA 125
INTRODUCTION Sevexal studies suggest that maternal serum alpha-fetoprotein (MS-AFP) levels are low in the first trimester when the fetus has Down’s syndrome (DS) (Brambati er al., 1986; Milunsky et al., 1988; Cuckle et al., 1988; Mantingh et al., 1989). Other biochemical factors in maternal serum, such as unconjugated oestriol (uE3), human chol-ionicgonadotropin (hCG), and pregnancy-specific beta-1-glycoprotein (SP- l), were evaluated and also appeared to be associated with DS (Cuckle et al., 1988; Brock et al., 1990). First-trimester screening for DS would have considerable advantages comparable to the advantages of first-trimester fetal karyotyping. We have started a multicentre trial to study the possibilities of first-trimester screening. Preliminary results on AFP and cancer antigen 125 (CA 125) are presented. PATIENTS AND METHODS Maternal blood samples were obtained before 13 weeks of gestation in a group of wornen undergoing chorionic villus sampling or amniocentesis. The indication to undergo such a procedure was mainly advanced maternal age, 36 years or older. The serum was removed and stored at - 20°C. Every 8 weeks the samples were collected and assayed in Groningen. Relevant patient characteristics were collected, such as gestational age by last menstrual period and by ultrasound measurement, and *F’articipatingprenatal diagnostic centres: University Hospital Groningen; A. Mantingh; Rijnstate Hospital Amhem; M. D. Kloosterman; Academic Medical Centre Amsterdam; H. Wolf; University Hospital Leiden; H. H. H. Kanhai; Medical Spectrum Twente Enschede; E. Everhardt; University Hospital Utrecht; G. C. M. L. Christiaens;Free University Hospital Amsterdam; J. M. G. Van Vugt; Laboratories,University Hospital Groningen; H. W. A. De Bruijn, J. J. Pratt.
0197-385 1/91/0806214l4$05.00 0 1‘391by John Wiley & Sons, Ltd.
Received 6 August 1990 Revised30 October 1990 Accepted 16 January 1991
622
J. M. M. VAN LITH
50
0
40
s
.
0
A
30
0
La F
U
y
20
L 10
0
8
9
10
11
Weeks of gestation Figure 1. First-trimester MS-AFP levels in 950 patients. The 0 . 5 , 0 6 and 1.0 multiples of the median (MOM)were calculatedand are shown."hie individual levels of MSAFP in the cases of fetal trisomiesare indicated(.: trisomy21,n=9; 0 :trisomy 18,n=2; f :trisomy9,n=1)
maternal weight. The patients will be followed up regarding the outcome of pregnancy. Up to now, 950 patients have: entered the study. In this group, a total of 12 autosomal trisomies occurred, of which 9 were Down's syndrome, 2 were trisomies 18, and 1 was trisomy 9. AFP was measured using the A bbote IMx AFP assay, an enzyme immunoassay. The sensitivity of the assay is approximately 0.4 ng/ml. The interassay variation is between 4 and 7 per cent. The CA 125 measurement was done using the Abbote CA 125 enzyme immunoassay. We measured CA 125 in 9 DS pregnancies and 27 controls, matched for gestational age. RESULTS In Figure 1 the results of the hlS-AFP levels in 950 patients are outlined. No adjustment has been made for influencing factors, such as maternal weight. The median values and multiples of the median, i.e., 0.5 and 0.6 MOM, were calculated
FIRST-TRIMESTER SCREENING FOR FETAL CHROMOSOMAL ABNORMALITIES
623
12 1.0 Md*l
1
9
0
+
0
06 MOM
6
0.5 Md*l
3
0
7
a
9
10
11
12
13
Weeks of gestation Figure 2. First-trimester MS-CA 125 levels in 9 Down’s syndrome ( 0 )and 27 control pregnancies (0). Median values are shown as dashed lines
and are shown. The individual levels of MS-AFP for the 12 cases in which fetal autosomal trisomies were detected are indicated. Two out of 12 trisomies were below 0.5 MOM; four were below 0.6 MOM. In the first trimester of pregnancy, the level of MS-CA 125 is increased above the normal level for non-pregnant women, in our assay 16 kU/1 (Jacobs and Bast, 1989; Kobayashi et al., 1989). The values for MS-CA 125 were lower in DS than in unaffected pregnancies and not elevated. At week 9 of gestation, the MS-CA 125 MOM for DS pregnancies was 0.351; at week 10, it was 0.50 (Figure 2). DISCUSSION T h e preliminary results on AFP confirm the study of Milunsky et al. (1988). Their methods were slightly different, in that they used gestational age based on ultrasound measurement and a radioimmunoassay to measure AFP. Furthermore, the incidence of autosomal trisomies in their group of 540 women was 4 in 100,while in our study population of 950 women it was 1.3 in 100. hlS-CA 125 appears to discriminate normal and DS pregnancies well and could be ti valuable tool in first-trimester DS screening. The low, non-elevated levels of
624
J. M. M. VAN LITH
MS-CA 125 in DS pregnancies could be caused by a less aggressive invasion of trophoblastic tissue (Van Lith el al., 1991). CONCLUSION
The AFP results look promising. The Abbot@ IMx A F P assay, which is easy to perform, has proven to be accurate. Our results suggest that MS-CA 125 in the first trimester is predictive for DS. Other factors such as oestriol, hCG, and SP-I await further evaluation. We hope to present these results shortly. ACKNOWLEDGEMENTS
I would like to thank J. R. Beekhuis, gynaecologist, for his advice, and B. De Wolf, R. De Vrij, M. Scholten, and C. IMeyer for their excellent technical assistance. This study was financially supported by the Stichting voor Erfelijkheidsvoorlichting Groningen. REFERENCES Brambati, B., Simoni, G., Bonacchi, I., Piceni, L. (1986). Fetal chromosomal aneuploidies and maternal serum alpha-fetoprotein levels in first trimester, Lancet, ii, 165-166. Brock, D.J.H., Barron, L., Hollowaiy, S., Liston, W.A., Hillier, S.G., Seppala, M. (1990). First-trimester maternal serum biochemical indicators in Down syndrome, Prenat. Diagn., 10,245-251. Cuckle, H.S., Wald, N.J., Barkai, G., Fuhrmann, W., Altland, K., Brambati, B., Knight, G., Palomaki, G., Haddow, J.E., Canick, J. (1988). First-trimester maternal biochemical screening for Down’s syndrome, Lnmcet, i, 851-852. Jacobs, I., Bast, R.C. (1989). The CA 125 tumour-associated antigen; a review of literature, Hum. Reprod., 4,1-12. Kobayashi, F., Sagawa, N., Nakaimura, K., Nonogaki, M., Fujii, S., Mori, T. (1989). Mechanism and clinical significance of elevated CA 125 levels in the sera of pregnant women, Am. J. Obstet. Gynecol., 160,563-566. Mantingh, A., Marrink, J., De Wolf, B., Breed, A.S.P.M., Beekhuis, J.R., Visser, G.H.A. (1989). Low maternal serum alpha-fetoprotein at 10 weeks’ gestation and fetal Down’s syndrome, Br. J. Obstet. Gynaecol., 96,499-500. Milunsky, A., Wands, J., Brambati, B., Bonacchi, I., Cume, K. (1988). First-trimester maternal serum alpha-fetoproteiin screening for chromosome defects, Am. J . Obstet. Gynecol., 159,1209-1213. Van Lith, J.M.M., Mantingh, A., Beekhuis, J.R., De Bruijn, H.W.A., Breed, A.S.P.M. (1991). First trimester CA 125 and Down syndrome, Br. J. Obstet. Gynaecol., in press.
1 1,621-624 (199 1)
:FIRST-TRIMESTER SCREENING FOR FETAL CHROMOSOMAL ABNORMALITIES. PRELIMINARY RESULTS I. M. M. VAN LITH, FOR THE DUTCH WORKING PARTY ON PRENATAL DIAGNOSIS* Department of Obstetrics and Gynaecology, University Hospital Groningen, Oostersingel59, 9713 EZ Groningen. The Netherlands
SUMMARY We have started a multicentre trial to study the possibilities of first-trimester maternal serum screening for fetal chromosomal abnormalities. Maternal blood samples were obtained befotre 13 weeks of gestation. We present the preliminary results of the first 950 patients on alpha-fetoprotein(AFP). Results on cancer antigen 125 (CA 125) in Down’s syndrome and nornial pregnancies are also presented. We conclude that the results on AFP are promising and that CA 125 might be predictive for fetal Down’s syndrome. KEY WORDS
First trimester Down’s syndrome Autosomal trisomy Alpha-fetoprotein CA 125
INTRODUCTION Sevexal studies suggest that maternal serum alpha-fetoprotein (MS-AFP) levels are low in the first trimester when the fetus has Down’s syndrome (DS) (Brambati er al., 1986; Milunsky et al., 1988; Cuckle et al., 1988; Mantingh et al., 1989). Other biochemical factors in maternal serum, such as unconjugated oestriol (uE3), human chol-ionicgonadotropin (hCG), and pregnancy-specific beta-1-glycoprotein (SP- l), were evaluated and also appeared to be associated with DS (Cuckle et al., 1988; Brock et al., 1990). First-trimester screening for DS would have considerable advantages comparable to the advantages of first-trimester fetal karyotyping. We have started a multicentre trial to study the possibilities of first-trimester screening. Preliminary results on AFP and cancer antigen 125 (CA 125) are presented. PATIENTS AND METHODS Maternal blood samples were obtained before 13 weeks of gestation in a group of wornen undergoing chorionic villus sampling or amniocentesis. The indication to undergo such a procedure was mainly advanced maternal age, 36 years or older. The serum was removed and stored at - 20°C. Every 8 weeks the samples were collected and assayed in Groningen. Relevant patient characteristics were collected, such as gestational age by last menstrual period and by ultrasound measurement, and *F’articipatingprenatal diagnostic centres: University Hospital Groningen; A. Mantingh; Rijnstate Hospital Amhem; M. D. Kloosterman; Academic Medical Centre Amsterdam; H. Wolf; University Hospital Leiden; H. H. H. Kanhai; Medical Spectrum Twente Enschede; E. Everhardt; University Hospital Utrecht; G. C. M. L. Christiaens;Free University Hospital Amsterdam; J. M. G. Van Vugt; Laboratories,University Hospital Groningen; H. W. A. De Bruijn, J. J. Pratt.
0197-385 1/91/0806214l4$05.00 0 1‘391by John Wiley & Sons, Ltd.
Received 6 August 1990 Revised30 October 1990 Accepted 16 January 1991
622
J. M. M. VAN LITH
50
0
40
s
.
0
A
30
0
La F
U
y
20
L 10
0
8
9
10
11
Weeks of gestation Figure 1. First-trimester MS-AFP levels in 950 patients. The 0 . 5 , 0 6 and 1.0 multiples of the median (MOM)were calculatedand are shown."hie individual levels of MSAFP in the cases of fetal trisomiesare indicated(.: trisomy21,n=9; 0 :trisomy 18,n=2; f :trisomy9,n=1)
maternal weight. The patients will be followed up regarding the outcome of pregnancy. Up to now, 950 patients have: entered the study. In this group, a total of 12 autosomal trisomies occurred, of which 9 were Down's syndrome, 2 were trisomies 18, and 1 was trisomy 9. AFP was measured using the A bbote IMx AFP assay, an enzyme immunoassay. The sensitivity of the assay is approximately 0.4 ng/ml. The interassay variation is between 4 and 7 per cent. The CA 125 measurement was done using the Abbote CA 125 enzyme immunoassay. We measured CA 125 in 9 DS pregnancies and 27 controls, matched for gestational age. RESULTS In Figure 1 the results of the hlS-AFP levels in 950 patients are outlined. No adjustment has been made for influencing factors, such as maternal weight. The median values and multiples of the median, i.e., 0.5 and 0.6 MOM, were calculated
FIRST-TRIMESTER SCREENING FOR FETAL CHROMOSOMAL ABNORMALITIES
623
12 1.0 Md*l
1
9
0
+
0
06 MOM
6
0.5 Md*l
3
0
7
a
9
10
11
12
13
Weeks of gestation Figure 2. First-trimester MS-CA 125 levels in 9 Down’s syndrome ( 0 )and 27 control pregnancies (0). Median values are shown as dashed lines
and are shown. The individual levels of MS-AFP for the 12 cases in which fetal autosomal trisomies were detected are indicated. Two out of 12 trisomies were below 0.5 MOM; four were below 0.6 MOM. In the first trimester of pregnancy, the level of MS-CA 125 is increased above the normal level for non-pregnant women, in our assay 16 kU/1 (Jacobs and Bast, 1989; Kobayashi et al., 1989). The values for MS-CA 125 were lower in DS than in unaffected pregnancies and not elevated. At week 9 of gestation, the MS-CA 125 MOM for DS pregnancies was 0.351; at week 10, it was 0.50 (Figure 2). DISCUSSION T h e preliminary results on AFP confirm the study of Milunsky et al. (1988). Their methods were slightly different, in that they used gestational age based on ultrasound measurement and a radioimmunoassay to measure AFP. Furthermore, the incidence of autosomal trisomies in their group of 540 women was 4 in 100,while in our study population of 950 women it was 1.3 in 100. hlS-CA 125 appears to discriminate normal and DS pregnancies well and could be ti valuable tool in first-trimester DS screening. The low, non-elevated levels of
624
J. M. M. VAN LITH
MS-CA 125 in DS pregnancies could be caused by a less aggressive invasion of trophoblastic tissue (Van Lith el al., 1991). CONCLUSION
The AFP results look promising. The Abbot@ IMx A F P assay, which is easy to perform, has proven to be accurate. Our results suggest that MS-CA 125 in the first trimester is predictive for DS. Other factors such as oestriol, hCG, and SP-I await further evaluation. We hope to present these results shortly. ACKNOWLEDGEMENTS
I would like to thank J. R. Beekhuis, gynaecologist, for his advice, and B. De Wolf, R. De Vrij, M. Scholten, and C. IMeyer for their excellent technical assistance. This study was financially supported by the Stichting voor Erfelijkheidsvoorlichting Groningen. REFERENCES Brambati, B., Simoni, G., Bonacchi, I., Piceni, L. (1986). Fetal chromosomal aneuploidies and maternal serum alpha-fetoprotein levels in first trimester, Lancet, ii, 165-166. Brock, D.J.H., Barron, L., Hollowaiy, S., Liston, W.A., Hillier, S.G., Seppala, M. (1990). First-trimester maternal serum biochemical indicators in Down syndrome, Prenat. Diagn., 10,245-251. Cuckle, H.S., Wald, N.J., Barkai, G., Fuhrmann, W., Altland, K., Brambati, B., Knight, G., Palomaki, G., Haddow, J.E., Canick, J. (1988). First-trimester maternal biochemical screening for Down’s syndrome, Lnmcet, i, 851-852. Jacobs, I., Bast, R.C. (1989). The CA 125 tumour-associated antigen; a review of literature, Hum. Reprod., 4,1-12. Kobayashi, F., Sagawa, N., Nakaimura, K., Nonogaki, M., Fujii, S., Mori, T. (1989). Mechanism and clinical significance of elevated CA 125 levels in the sera of pregnant women, Am. J. Obstet. Gynecol., 160,563-566. Mantingh, A., Marrink, J., De Wolf, B., Breed, A.S.P.M., Beekhuis, J.R., Visser, G.H.A. (1989). Low maternal serum alpha-fetoprotein at 10 weeks’ gestation and fetal Down’s syndrome, Br. J. Obstet. Gynaecol., 96,499-500. Milunsky, A., Wands, J., Brambati, B., Bonacchi, I., Cume, K. (1988). First-trimester maternal serum alpha-fetoproteiin screening for chromosome defects, Am. J . Obstet. Gynecol., 159,1209-1213. Van Lith, J.M.M., Mantingh, A., Beekhuis, J.R., De Bruijn, H.W.A., Breed, A.S.P.M. (1991). First trimester CA 125 and Down syndrome, Br. J. Obstet. Gynaecol., in press.
