Human Reproduction, Vol. 14, No. 8, 2120-2123,
August 1999
© 1999 European Society of Human Reproduction and Embryology
Maternal serum alpha-fetoprotein and human chorionic gonadotrophin in pregnancies conceived after intracytoplasmic sperm injection and conventional in-vitro fertilization
Department of Obstetrics and Gynaecology, The University of Hong Kong, Hong Kong, China
 |
Abstract |
|---|
 Top Abstract IntroductionMaterials and methodsResultsDiscussionReferences |
|---|
Data in the Caucasian population suggest that maternal serum alpha-fetoprotein (AFP) and unconjugated oestriol concentrations are reduced and human chorionic gonadotrophin (HCG) concentrations are elevated in pregnancies conceived after in-vitro fertilization (IVF), leading to a higher than expected Down's syndrome screen-positive rate. There are no previous reports on the serum marker values in pregnancies conceived after intracytoplasmic injection (ICSI). Between 1996 and 1998, we measured maternal serum total HCG and AFP concentrations between 15 and 20 weeks gestation in 42 in-vitro fertilization (IVF) pregnancies and 23 ICSI pregnancies with known normal outcome. The results were compared with that of 2799 naturally occurring singleton pregnancies who were known to have a normal outcome. Median AFP multiple of the median (MOM) in ICSI pregnancies was significantly reduced to 0.76 compared with both that of the controls and that of the IVF pregnancies. For the IVF pregnancies, median HCG MOM was elevated to 1.15, and median AFP MOM was reduced to 0.88 compared with the controls, but these differences were not statistically significant. In both the IVF and ICSI pregnancies the changes might result in a falsely high Down's syndrome risk. In particular, the reduced AFP concentration in ICSI pregnancies was substantial. If this preliminary finding is substantiated by other series, the appropriate adjustment needs to be made to allow for valid interpretation of the screen result and to avoid an unnecessarily high false positive rate.
Key words: alpha-fetoprotein/Down's syndrome/human chorionic gonadotrophin/ICSI/IVF–embryo transfer
|
Introduction |
|---|
|
TopAbstractIntroductionMaterials and methodsResultsDiscussionReferences |
|---|
A woman carrying a Down's syndrome pregnancy has lower serum alpha-fetoprotein (AFP) (Cuckle et al., 1984
), lower serum unconjugated oestriol (Canick et al., 1988) and higher serum human chorionic gonadotrophin (HCG) (Wald et al., 1988) concentrations in the second-trimester. The use of AFP, HCG and oestriol with maternal age to screen for fetal Down's syndrome has been validated by prospective studies including more than 70 000 women (Haddow et al., 1992; Phillips et al., 1992; Wald et al., 1992a; Goodburn et al., 1994). Serum screening has become an established practice in many Western and Asian countries (Cuckle, 1992; Palomaki et al., 1993a; Hsu et al., 1996; Onda et al., 1996; Lam et al., 1998). However, serum concentrations of AFP, HCG and oestriol are affected by maternal weight (Palomaki et al., 1990), multiple gestation (Alpert et al., 1990), diabetes mellitus (Wald et al., 1992b), smoking (Palomaki et al., 1993b) and race (Simpson et al., 1990). Under these circumstances, appropriate adjustments need to be made to allow a valid interpretation of individual results and to optimize the efficacy of the screening programme. Recently, data from Europe and the United States suggested that maternal serum AFP, HCG and oestriol concentrations may be altered in pregnancies conceived after in-vitro fertilization (IVF) (Heinonen et al., 1996; Ribbert et al., 1996; Frishman et al., 1997), leading to a higher than expected Down's syndrome screen-positive rate (Ribbert et al., 1996; Frishman et al., 1997). We speculate that similar changes may be found in pregnancies conceived after intracytoplasmic injection (ICSI). The purpose of this study was to compare the serum concentrations of AFP and HCG in pregnancies conceived after ICSI and conventional IVF with that of the spontaneously conceived pregnancies in an Asian population. |
Materials and methods |
|---|
|
TopAbstractIntroductionMaterials and methodsResultsDiscussionReferences |
|---|
ICSI and IVF
The procedure for our assisted reproduction programme has been described previously (Yeung et al., 1996
). Briefly, patients were down-regulated with intranasal gonadotrophin-releasing hormone agonist (GnRHa; buserelin; Suprecur, Hoechst), 150 µg 4 times daily starting from day 21 of the preceeding cycle. They were stimulated with human menopausal gonadotrophin if their serum 17ß-oestradiol concentration was basal and pelvic ultrasound scan was normal on day 2 of the treatment cycle. The ovarian response was monitored by serum 17ß-oestradiol and pelvic ultrasonography. An ovulating dose of HCG 10 000 IU was given when the leading follicle was 
18 mm, and at least three follicles were >15 mm in diameter. Oocytes were retrieved under transvaginal ultrasound guidance 36–38 h after HCG injection, and inseminated or assisted fertilized by intracytoplasmic sperm injection 4–6 h after retrieval. Intracytoplasmic sperm injection was performed under an inverted microscope (Nikon, Japan) equipped with an incubation chamber, Hoffman contrast optics and two micromanipulators (Narishige, Japan). Spermatozoa were immobilized in PVP-HEPES buffered Earle's balanced salt solution before injection. Fertilization of oocytes was confirmed by the presence of two pronuclei 16–20 h after insemination or micromanipulation. The fertilized zygotes were cultured in Earle's balanced salt solution for a further 24 h before replacement. A maximum of three embryos was replaced. Luteal phase was supported by two booster doses of HCG 1500 IU i.m. 5 days apart. Pregnancy tests were performed 20 days after the ovulatory dose of HCG, and fetal development was assessed by ultrasound examination 10 days later.
Screening for Down's syndrome
Women who conceived after ICSI or IVF were referred to Tsan Yuk Hospital for counselling on the risk of fetal chromosomal disorders. Women who were 35 years old at the expected date of confinement or who conceived after ICSI could choose to undergo amniocentesis directly, and a blood sample would be taken for AFP and HCG assay just prior to amniocentesis for this study. Women <35 years were offered AFP and HCG screening for fetal Down's syndrome. Those pregnancies with more than one gestational sac seen on ultrasound examination 5–6 weeks after ICSI or IVF were excluded from this study. Although the date of embryo transfer was known, the gestational age was ascertained by ultrasound measurement of the fetal crown–rump length or biparietal diameter. All blood samples were taken at 15–20 weeks of gestation. Total HCG and AFP concentrations were measured by a microparticle enzyme immunoassay as described previously (Lam et al., 1998). Because AFP and HCG concentrations change with gestation, the results were expressed as multiples of the median (MOM) of the gestational week. The results were compared with those of 2799 naturally occurring singleton pregnancies (as controls) who had serum screening at 15–20 weeks (ascertained by ultrasound examination) at the same laboratory over the same period of time, whose babies were known to be normal at birth. Table I shows the median HCG and AFP concentrations used to compute the MOM. All the case and control MOM were adjusted for maternal weight at sampling. Statistical analysis was performed by SPSS 6.1 computer software. All the variables were checked for a normal distribution by a normal probability plot. Differences of the variables between groups were analysed by the Wilcoxon rank-sum test or two-tailed Student's t-test, whichever was appropriate. A P value of < 0.05 was considered statistically significant.
|
|
Results |
|---|
|
TopAbstractIntroductionMaterials and methodsResultsDiscussionReferences |
|---|
Between 1996 and 1998, 42 women who conceived after conventional IVF and 24 women who conceived after ICSI (15 from ejaculated spermatozoa, seven from epididymal spermatozoa, two from testicular spermatozoa) were recruited for study. Twenty-seven of these women had amniocentesis and karyotyping and one pregnancy (conceived after ICSI) was affected by 47, XXY. This case was excluded from the final analysis. All the other babies of the cases and controls did not show signs of chromosomal abnormalities at birth. Table II
summarizes the maternal age and gestational age at blood sampling of the cases and controls. Women who conceived after either conventional IVF or ICSI were significantly older than the controls (P < 0.005, two-tailed t-test). Table III shows the AFP MOM and HCG MOM of the cases and controls. Median AFP MOM of the ICSI pregnancies was significantly reduced to 0.76 compared with both that of the controls and that of the IVF pregnancies. For the IVF pregnancies, HCG MOM was 22% higher and AFP MOM was 6% lower than that of the controls, but these differences were not statistically significant (P = 0.07, and 0.95 respectively).
|
|
|
Discussion |
|---|
|
TopAbstractIntroductionMaterials and methodsResultsDiscussionReferences |
|---|
Our findings of a trend towards higher HCG concentrations and lower AFP concentrations in IVF pregnancies agree with previous observations (Ribbert et al., 1996
; Frishman et al., 1997). An even higher extent of elevation of HCG concentrations to a mean MOM of 1.53 has been found, but AFP concentrations in that series of IVF pregnancies were unaltered (Heinonen et al., 1996). The largest series of serum screening data in IVF pregnancies has been reported (Barkai et al., 1996). In contrast to the above studies, they did not find a significant difference in AFP and HCG concentrations in the IVF pregnancies (Table IV). The weighted geometric mean of all the reported results shows that on average, AFP is 5% lower and HCG is 9% higher in IVF pregnancies compared with that of the controls (Table IV). The exact cause of this observation is unknown. However, both the AFP and HCG changes are in the direction of an increased Down's syndrome risk. This leads to a higher than expected false positive rate. In 1996, out of a series of 67 IVF pregnancies, 17 were screen positive instead of the expected number of 14 (Ribbert et al., 1996). The inflated false-positive rate became twice the expected rate if unconjugated oestriol was used in addition to AFP and HCG to screen for Down's syndrome (Frishman et al., 1997). Thus, it seems appropriate to adjust the AFP and HCG values in IVF pregnancies. The corrected MOM can be used to derive a more accurate risk of Down's syndrome and to avoid an unnecessarily high false positive rate.
|
There are no previous reports on the AFP and HCG concentrations in ICSI pregnancies. In the present series, despite the small number of cases, we found a statistically significant reduction of AFP concentrations in ICSI pregnancies compared with both that of the controls (by 19%) and that of the IVF pregnancies (by 16%). We cannot offer an explanation for this finding. Factors known to be associated with a low maternal serum AFP concentration include insulin-dependent diabetes mellitus (Wald et al., 1992b
), young maternal age (Wald and Watt, 1996), Down's syndrome pregnancy (Cuckle et al., 1984) and sex aneuploidies (Lustig et al., 1988). In the present series, none of the women who conceived after ICSI had insulin-dependent diabetes mellitus. They were on average 5 years older than the controls. Because AFP concentration increases with maternal age by 4.4% per 10 year increment (Wald and Watt, 1996), the observed reduction in AFP concentrations in ICSI pregnancies was already underestimated. None of the ICSI pregnancies was affected by Down's syndrome. However, we did not rule out sex chromosome aberrations in every ICSI case. Since the risk of sex chromosome aberrations in ICSI pregnancies is only ~1% (Bonduelle et al., 1998), its contribution to the low AFP concentration in this series was likely to be small.
There is a high frequency of chromosomal abnormalities in both the male and female partners of couples undergoing ICSI (Mau et al., 1997; Meschede et al., 1998a). This, together with the increased risk of sex chromosomal abnormalities in ICSI pregnancies, explains why most women who conceived after ICSI are counselled to undergo chorionic villus sampling or amniocentesis. However, if they were given the choice of non-invasive tests such as ultrasound and serum screening, 83% would not wish to undergo an invasive test (Meschede et al., 1998b). If our preliminary finding of a reduced AFP concentration in ICSI pregnancies is substantiated by a larger series, appropriate adjustment needs to be made to allow a valid interpretation of the screen result and to avoid an unnecessarily high false positive rate. It also remains to be found out whether AFP and HCG concentrations will differ in response, depending on whether ejaculated, epididymal or testicular spermatozoa are used for the ICSI.
|
Notes |
|---|
1 To whom correspondence should be addressed at: University Office, Tsan Yuk Hospital, 30 Hospital Road, Sai Ying Pun, Hong Kong, China
|
References |
|---|
|
TopAbstractIntroductionMaterials and methodsResultsDiscussionReferences |
|---|
Alpert, A., Greenberg, F., Conant, C. et al. (1990) Serum hCG, AFP and unconjugated estriol levels in twin pregnancies in mid-trimester. Am. J. Hum. Genet, 47, a267.
Barkai, G., Goldman, B., Ries, L. et al. (1996) Down's syndrome screening marker levels following assisted reproduction. Prenat. Diagn., 16, 1111–1114.[Web of Science][Medline]
Bonduelle, M., Aytoz, A., Van Assche, E. et al. (1998) Incidence of chromosomal aberrations in children born after assisted reproduction through intracytoplasmic sperm injection. Hum. Reprod., 13, 781–782.
Canick, J., Knight, G.J., Palomaki, G.E. et al. (1988) Low second trimester maternal serum unconjugated oestriol in pregnancies with Down's syndrome. Br. J. Obstet. Gynaecol., 95, 330–333.[Web of Science][Medline]
Cuckle, H. (1992) Screening for Down's syndrome. Br. Med. J., 305, 1504.
Cuckle, H.S., Wald, N.J. and Lindenbaum, R.H. (1984) Maternal serum alpha-fetoprotein measurement. A screening test for Down syndrome. Lancet, i, 926–929.
Frishman, G.N., Canick, J.A., Hogan, J.W. et al. (1997) Serum triple-marker screening in in-vitro fertilization and naturally conceived pregnancies. Obstet. Gynecol., 90, 98–101.[Web of Science][Medline]
Goodburn, S.F., Yates, J.R.W., Raggat, P.R. et al. (1994) Second-trimester maternal serum screening using alpha-fetoprotein, human chorionic gonadotrophin and unconjugated oestriol: experience of a regional programme, Prenat. Diagn., 14, 391–402.[Web of Science][Medline]
Haddow, J.E., Palomaki, G.E., Knight, G.J. et al. (1992) Prenatal screening for Down's syndrome with use of maternal serum markers. N. Engl. J. Med., 327, 588–593.[Abstract]
Heinonen, S., Hippéläinen, M., Ryynänen, M. et al. (1996) Effect of in-vitro fertilization on human chorionic gonadotropin serum concentrations and Down's syndrome screening. Fertil. Steril., 66, 398–403.[Web of Science][Medline]
Hsu, J.J., Hsieh, T.T. and Hsieh, F.J. (1996) Down syndrome screening in an Asian population using alpha-fetoprotein and free ß-hCG: a report of the Taiwan Down syndrome screening group. Obstet. Gynecol., 87, 943–947.[Medline]
Lam, Y.H., Ghosh, A., Tang, M.H.Y. et al. (1998) Second-trimester maternal serum alpha-fetoprotein and human chorionic gonadotrophin screening for Down's syndrome in Hong Kong. Prenat. Diagn., 18, 585–589.[Web of Science][Medline]
Lustig, L., Clark, S., Cunningham, G. et al. (1988) California's experiences with low MS-AFP results. Am. J. Med. Genet., 31, 211–222.[Medline]
Mau, U.A., Bäckert, I.T., Kaiser, P. and Kiesel, L. (1997) Chromosomal findings in 150 couples referred for genetic counselling prior to intracytoplasmic sperm injection. Hum. Reprod., 12, 930–937.
Meschede, D., Lemcke, B., Exeler, J.R. et al. (1998a) Chromosome abnormalities in 447 couples undergoing intracytoplasmic sperm injection – prevalence, types, sex distribution and reproductive relevance. Hum. Reprod., 13, 576–582.
Meschede, D., Lemcke, B., Stüssel, J. et al. (1998b) Strong preference for non-invasive prenatal diagnosis in women pregnant through intracytoplasmic sperm injection (ICSI). Prenat. Diagn., 18, 700–705.[Web of Science][Medline]
Onda, T., Kitagawa, M., Takeda, O. et al. (1996) Triple marker screening in native Japanese women. Prenat. Diagn., 16, 713–717.[Medline]
Palomaki, G.E., Panizza, D.S. and Canick, J.A. (1990) Screening for Down syndrome using AFP, µE3 and hCG. Effect of maternal weight. Am. J. Hum. Genet., 47, a282.
Palomaki, G.E., Knight, G.J., McCarthy, J. et al. (1993a) Maternal serum screening for fetal Down syndrome in the United States: a 1992 survey. Am. J. Obstet. Gynecol., 169, 1558–1562.[Web of Science][Medline]
Palomaki, G.E., Knight, G.J., Haddow, J.E. et al. (1993b) Cigarette smoking and levels of maternal serum alpha-fetoprotein, unconjugated oestriol and human chorionic gonadotropin: impact on Down syndrome screening. Obstet. Gynecol., 81, 675–678.[Web of Science][Medline]
Phillips, O.P., Elias, S., Shulman, L.P. et al. (1992) Maternal serum screening for fetal Down's syndrome in women less than 35 years of age using alpha-fetoprotein, hCG and unconjugated estriol: a prospective 2-year study. Obstet. Gynecol., 80, 353–358.[Web of Science][Medline]
Ribbert, L.S.M., Kornman, L.H., De Wolf, B.T.H.M. et al. (1996) Maternal serum screening for fetal Down syndrome in IVF pregnancies. Prenat. Diagn., 16, 35–38.[Web of Science][Medline]
Simpson, J.L., Elias, S., Morgan, C.D. et al. (1990) Second trimester maternal serum human chorionic gonadotrophin and unconjugated oestriol levels in blacks and whites. Lancet, i, 1459–1460.
Wald, N.J. and Watt, H.C. (1996) Serum markers for Down's syndrome in relation to number of previous births and maternal age. Prenat. Diagn., 16, 699–703.[Web of Science][Medline]
Wald, N.J., Cuckle, H.S., Densem, J.W. et al. (1988) Maternal serum screening for Down's syndrome in early pregnancy. Br. Med. J., 87, 883–888.
Wald, N.J., Kennard, A., Densem, J.W. et al. (1992a) Antenatal maternal serum screening for Down's syndrome: results of a demonstration project. Br. Med. J., 305, 391–394.
Wald, N.J., Cuckle, H.S., Densem, J.W. and Stone, R. (1992b) Maternal serum unconjugated oestriol, human chorionic gonadotropin and alpha-fetoprotein levels in pregnancies with insulin-dependent diabetes: implications for Down's syndrome screening. Br. J. Obstet. Gynecol., 99, 51–53.[Web of Science][Medline]
Yeung, W.S.B., Lau, E.Y.L., Chan, S.T.H. and Ho, P.C. (1996) Coculture with homologous oviductal cells improved the implantation of human embryos – a prospective randomized control trial. J. Assist. Reprod. Genet., 13, 769–774.
Submitted on January 25, 1999; accepted on April 15, 1999.
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  P.A. Nepomnaschy, C.R. Weinberg, A.J. Wilcox, and D.D. Baird Urinary hCG patterns during the week following implantation Hum. Reprod., February 1, 2008; 23(2): 271 - 277. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. D. Pan, I. Peter, G. M. Lambert-Messerlian, J. A. Canick, D. W. Bianchi, and K. L. Johnson Cell-free fetal DNA levels in pregnancies conceived by IVF Hum. Reprod., November 1, 2005; 20(11): 3152 - 3156. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Bellver, C. Lara, S. R. Soares, A. Ramirez, A. Pellicer, J. Remohi, and V. Serra First trimester biochemical screening for Down's syndrome in singleton pregnancies conceived by assisted reproduction Hum. Reprod., September 1, 2005; 20(9): 2623 - 2627. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P.W. Hui, M.H.Y. Tang, Y.H. Lam, E.H.Y. Ng, W.S.B. Yeung, and P.C. Ho Maternal serum hCG and alpha-fetoprotein levels in pregnancies conceived after IVF or ICSI with fresh and frozen-thawed embryos Hum. Reprod., March 1, 2003; 18(3): 572 - 575. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. Maymon and A. Shulman Serial first- and second-trimester Down's syndrome screening tests among IVF-versus naturally-conceived singletons Hum. Reprod., April 1, 2002; 17(4): 1081 - 1085. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Perheentupa, A. Ruokonen, L. Tuomivaara, M. Ryynanen, and H. Martikainen Maternal serum {beta}-HCG and {alpha}-fetoprotein concentrations in singleton pregnancies following assisted reproduction Hum. Reprod., March 1, 2002; 17(3): 794 - 797. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. Raty, A. Virtanen, P. Koskinen, L. Anttila, J. Forsstrom, P. Laitinen, P. Morsky, A. Tiitinen, and U. Ekblad Serum free {beta}-HCG and alpha-fetoprotein levels in IVF, ICSI and frozen embryo transfer pregnancies in maternal mid-trimester serum screening for Down's syndrome Hum. Reprod., February 1, 2002; 17(2): 481 - 484. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y. Yaron, O. Lehavi, A. Orr-Urtreger, I. Gull, J. B. Lessing, A. Amit, and D. Ben-Yosef Maternal serum HCG is higher in the presence of a female fetus as early as week 3 post-fertilization Hum. Reprod., February 1, 2002; 17(2): 485 - 489. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A.W. Liao, V. Heath, N. Kametas, K. Spencer, and K.H. Nicolaides First-trimester screening for trisomy 21 in singleton pregnancies achieved by assisted reproduction Hum. Reprod., July 1, 2001; 16(7): 1501 - 1504. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. Maymon and A. Shulman Comparison of triple serum screening and pregnancy outcome in oocyte donation versus IVF pregnancies Hum. Reprod., April 1, 2001; 16(4): 691 - 695. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R.S. Gold, F. Azem, I. Yovel, I. Wagman, A. Amit, and J.B. Lessing Does ICSI affect early serum {beta}-HCG in pregnancies achieved after IVF? Hum. Reprod., June 1, 2000; 15(6): 1221 - 1224. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||