In contrast, neither Greenfeld and Klock (2001) nor Cox et al.
(2006) found differences in self-esteem or maternal self-efficacy
between ART and SC groups at any point post-partum. Selection
biases might have governed these findings. In Greenfeld and
Klock’s (2001) study, 29% of ART participants were mothers of
twins or triplets compared with only 4% in the comparison
group. Although there are generally poorer health outcomes in
multiple than singleton infants, these mothers all assessed infant
health as good. Further, of the 97 ART participants, only 53
(55%) were retained at the 9 month final assessment, and it is
possible that those experiencing most difficulties were lost to
follow-up. Similarly Cox et al. (2006) had very low recruitment
and retention rates. The possibility that infertility-related diminished
self-confidence persists after childbirth cannot be excluded.