Effectiveness of the System
The effectiveness of the Creighton Model System has been extensively studied and a meta-analysis of the system incorporating the data from five separate studies into a composite which includes 1,876 couples over 17,130 couple months of use has been published. These studies all utilizing life-table analysis and an objective assessment of pregnancies, reported the range of the method-effectiveness to avoid pregnancy at the 12th ordinal month to be 98.7 to 99.8 (with the five-study composite 99.5). The use-effectiveness to avoid pregnancy for the same time period ranged from 94.6 to 97.9 and was shown to continually improve over the 14 years of the studies (the five-study composite was 96.8) (Table 15-28).
[Table 15-28 from p. 209 from the NaPro textbook]
*"NaProTECHNOLOGY" is a registered trademark of the Pope Paul VI Institute for the Study of Human Reproduction. It can be freely used by any person or entity so long as its use reflects the medical concepts and values expressed in the textbook The Medical & Surgical Practice of NaProTECHNOLOGY.