Table III.

Illustrative sample sizes for different absolute improvements in LBR and different control group birth rates.

Absolute Improvement in LBR	2-pp	5-pp	10-pp
Control group	LBR Sample size (N)
Power = 80%
5%	4424	868	280
10%	7682	1372	398
20%	13 018	2188	586
30%	16 786	2752	712
Power = 90%
5%	5922	1162	374
10%	10 282	1834	532
20%	17 428	2928	784
30%	22 472	3684	952

Numbers shown are overall numbers required in a two-arm trial with a 1:1 allocation ratio.