anembryonic pregnancy and early missed abortion were \elected on the basis of ultrasonographic. ( SO) diagnosis. Products of conception (POC) at termination ...
'[!fiIfJJ[~;* Venice, Ma
00
EXTREME SKEWI G OF SEX RATIO IN RECURRENT EARLY MISSED ABORTIONS Halder A, Fauzdar A. Kumar A Deparl/1/l>llf o(Reprodl/l'fi!'l' Hi%gr All I"dia I1nritllle oIM(,tliw/ SC;t'fI("('\, \'nl' /)l'1hj, India
INTRODUCTION Approximately 15-20 ck of clinically recogni/cd prt:gnancie\ an: "'pontancou\ly aborted. mostly during fir... t trimester (I). Most of the"'c ahortion ... arc carly miv..cd abortion & ancl1lbryonic pregnancy. Several etiologies such a ... chrolllo\omal abnormalitie .... hOfmonal imbalances. polycystic ovarian syndrome. immunological and problems of UtCHI" hu\ been attributed (2.3). Cytogenetic study of spontaneous abortion ha ... rc\calcd thaL chromm.omul abnormality i... major contributing cause in about 50-60% (4-7). Chromo\omal analy\is of aborted fetu ... b important for prognostication (8,9) because it gives information on frcqucnL:y & type of ehromo:-.omal abnormality, on etiology and risk assessment for future prcgnancie.. . (5.10). Cytogcnctic evaluation of chromo~omally normal spontaneous abortion ... had gi\cn conflicting result ... about se, ratio (5.11-13). Most of the ~tudie~ indicated greater number... of female (1-J.-21). Scveral reasons for execs... of females in spontaneous aborted samples ha... bcen proposed. and it has reported that the type of tissue used in culture largely influence ...ex ratio. MO....1 .... ignilicant factor influencing the . . e' ratio i.. . the presence of different frequency of contamination and o\'ergrovvth of ti . . sue culture.. . by maternal cell contamination (22-25). A routine cla.. . . . ical cytogenetics analysis of early missed abortion product face certain limitations ... uch as rb~ of contamination. culture failure. maternal eell growth and laborious as well as time con . . uming. In our pn: cnt ...tud) \\-e O\'ercome all these difficulties by using molecular cytogenetics. We undertook thi study to eliminate the bia~e . . 01 conventional cytogenetic analysis due 10 selected succes.. . fu[ ca es. clonal selection. rc.qriction to dividing cell population... and maternal cell contamination..... Our aim to carry out ,hi .......tudy wa... cytogenetic analy~is recurrent spontaneou~ abortion ... (ancmhryonic and earl) miv..cd abortion) and to detect frequency and type of mo.. . ' common chromo.. .omal ahnormality u.. . ing FISH in addition to ~cx ralio.
(i Cnryn~ht :!OO.5.
ClC LJi7ioni lntcmlllionali - Rome \11 righh re-.cnoo '\0 part of thi.. publication m:!) he rcpn'll.lucoo \Irdi,tritouled II .. n~ !I'ml I'r to~ rctnc\al '~'Iem..... ithoullhe priOf \H;tten pennb'lon oj Ih". puhlr,h..·r
69
an~
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MATERIAL & METHOD Samples were obtained from women with recurrent ""ponlancous abortion. Fifty-eight casel., of
anembryonic pregnancy and early missed abortion were \elected on the basis of ultrasonographic ( SO) diagnosis. Products of conception (POC) at termination were collected in saline from all the ca\cs after cleaning from maternal blood. Chorionic \ II Iou ... li\\uc \\;a... carefully removed from decidual tissue with the help of inverted microscope to avoid possibility of maternal cell contamination. Each sample was divided into three partapproved by FISH (tetraploidy. cultural artifact). Interphase probe HSH was carried oul in all with centromere specifie probe for chromosome X, Y, 1,9. 12. 16& 18 on all 58 ,ample,. It resealed that 54 (93q·) were chromosomally normal and 4 (6.8CK) were chromosomally abnormal. Comparative Genomic Hybridization (CGH) was carried out in ten. eight were inform:.tti\e and four were chromosomally normal. None of the case was aneuploid. however. fuur showed suspected areas of gain or loss (to be proved).
Table 1 Parameters
Cytogenetics
Total number of samples analyzed Chromosomally normal Chromosomally abnormal
I
CGH
j:
15
--+ 12 (80%L
58
t50%)
4 suspected
03 (20%)
FISH IX, Y, 1, 9, 12,16 & 18)
154 (93%) 04 (7%)
(galn~oss)
Tetraploidy Triploidy___ Trisomy Aneuploidy Rate
__ _-+01
0
_~o
0
01
0
01tCh.16)
01(Ch.18)
F
0_%
70
100
...L7_%
_
Table 2 CGH
FISH
Spontaneous Abortions «12 wks)
Cytogenetics
46,XY
03
2
15
46,XX
12
6
43
Sex Ratio (Male: Femalel
1:4
13
Terminations «12 wks)
NO
r f" o
88
46,XY 46,XX Sex Ratio --Preimplantation Embryo (1-4 celt)
n=154 66
1.3:1
NO
NO
n=32
46,XY
21
46,XX
11
Sex Ratio
1.9:1
Investigation through both conventional & molecular c}lOgcnctics in our study (Tahle 2) had revealed that there is great alteration in sex ratio in spontaneou... abortions (I M:2.9F). pregnancy terminations (1.3M: IF) & preimplantation mouse embryo (1.9M: I F).
DISCUSSION Chromosome abnormality particularly aneuploidy in our study was not as quoted in literature. 5060% (2,4,5,16,23). Our result shows that aneuploidy ratc is much lower. through conventional
cytogenetics 20% (corrected I39'r), through CGII Os( and through FISH 7 c/c for chromosomes X. Y. I. 12. 16 & 18. Rarity in aneuploidy rate may be due to smaller number of samples analyled through conventional cylogenelic\ and fewer probe... lc... red through FISH or other idiopathic reason. Chromo\ome I aneuploidy was excluded from all our ...amplc\. It ... lIpport... previou ... observation lhal chromosome I abnormalily i... incompalible for implantation (:27.28). Howe\'er. chromosome 16 aneuploidy, which is commonest in "'ponlancoll... abonioll (29-31). wa ... found only in one sample. All the ca...es in our ...tudy had previou... hi"tory of ...imilar abonion and in\'c....igaled. We have ruled out hormonal. anatomical. immunological (ulilOimmllnc) & chromosomal (of parents) causes. however other causes including alloil11l11l1ne have not been rulcd oul. Primary sex ratio theoretically should be I: I. Ilowe,cr. ,ex ralio at prcimplanlalion embryo (32) i, about 1.05M: I F (day 3 embryo) to 1.34 M: I F (blastocyst \lage embryo). Our own data from 32 mouse embryo (n=32) is 1.9M: I F. Sex ratio at fi"t trime\lcr CYS is about 1.28M: I F (our own data from 154 cases is 1.31M:lF), second trimester
