In vitro fertilisation and stage 3 retinopathy of prematurity

To re-examine the risk of children born by assisted conception developing stage 3 retinopathy of prematurity (ROP) and to define whether the risk of ROP varies with the method of assisted conception.

This was a retrospective study carried out between December 1995 and December 1998 of infants in a single neonatal unit serving the Brent and Harrow area of North West Thames requiring screening and treatment of ROP. The infants screened were identified from the ROP screening database. Those conceived by in vitro fertilisation (IVF) and other forms of assisted conception were identified by reviewing the neonatal notes and the maternal obstetric records. Birth weight, gestational age and the type of assisted conception were recorded. The presence or absence of any stage of ROP, its location and severity and the cases requiring treatment were recorded.

One hundred and seventy-nine infants fulfilled the screening criteria during this period. Acute ROP was detected in 32.4% (58 infants) and stage 3 ROP developed in 15.6% (28 infants). Twenty-one infants (11.7%) were born after assisted conception, with 12 (6.7%) being conceived by IVF. The others were conceived on clomiphene (8) or after intrauterine insemination (1). Assisted conception accounted for 21.4% of all those reaching stage 3 disease and 28.6% of those infants requiring treatment. Of the 12 infants conceived by IVF, 41.6% (5 infants) developed acute ROP which progressed to threshold ROP in all infants (100%). Of the assisted conception babies requiring treatment for ROP, 83.3% were conceived by IVF. The other child had been conceived on clomiphene. The gestational age and birth weight of the IVF infants reaching stage 3 ROP were 26.6 +/- 0.89 weeks and 937 +/- 170.2 g. The gestational age and birth weight in the rest of the infants reaching stage 3 ROP were lower than in those conceived by assisted conception (25.739 +/- 1.13 weeks and 735.29 +/- 117.70 g); however, this did not approach statistical significance (p = 0.35 and p = 0.13, respectively).

In this study 11.7% of the group requiring screening were conceived by assisted conception. Of all babies requiring treatment for ROP, 28.6% were born after assisted conception. Of the assisted conception group, 83.3% were conceived by IVF. Assisted conception using IVF rather than other techniques appears to be the major risk factor for the development of threshold ROP. We would advise increased vigilance when screening babies conceived by the IVF methods of assisted conception.