Table 2 Previous studies of T21 mosaicism in mothers with Down's pregnancies where not only blood and skin but also ovarian cells have been analysed

Blood

Skin

1

(6.0)*

(6.0)*

left

(92.0) *

Taylor et al. 1970

right

(88.5) *

1

2/101 (1.98)

0/92 (0.0)

2/35

(5.71)

Parke et al. 1980

1

12/162 (7.4)

82/102 (2.0)

left 22/100

(22.0)

Uchida et al 1985

right 84/100

(84.0)

9

0/260 (0.0)

0/21(0.0)

12/79

(15.2)

Nielsen et al 1988

4

3/100 (3.0)

(14.0)*

left

(47.0) *

Sachs et al. 1990

right

(44.0) *

3

(0.0)*

8/20

(0.4)

Tseng et al 1994

4

(0.0)*

3/4 oocytes

(75.0)

Cozzi et al 1999

4/7 embryos

(57.0)