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Updated: May 21, 2026

Human Blastocyst Biopsy and Vitrification
Published on: July 26, 2019
Natural procreative technology for infertility and recurrent miscarriage: outcomes in a Canadian family practice
Elizabeth Tham1, Karen Schliep, Joseph Stanford
1Department of Family and Community Medicine, University of Toronto, Ontario, Canada.
Objective:
To study the outcomes of women with infertility or miscarriage treated with natural procreative technology (NaProTechnology or NPT), a systematic medical approach to promoting conception in vivo; and to compare the outcomes with those previously published from a general practice in Ireland.
Design:
Retrospective cohort study.
Setting:
An urban Canadian primary care practice in which the physician had a part-time practice in NPT.
Participants:
Couples with infertility or recurrent miscarriage who received treatment in the practice between August 2000 and July 2006.
Intervention:
All couples were taught to identify the fertile time of their menstrual cycles using the Creighton Model FertilityCare System (CrMS) and completed a standard NPT evaluation. Many also received additional medical treatment to enhance conception in vivo.
Main Outcome Measures:
Live birth was the primary outcome; secondary outcomes included conceptions, multiple births, low birth weight, and prematurity.
Results:
A total of 108 couples received NPT and were included in the analysis, of which 19 (18%) reported having 2 or more previously unexplained miscarriages. The average female age was 35.4 years. Couples had been attempting to conceive for a mean of 3.2 years. Twentytwo participants (20%) had previously given birth; 24 (22%) had previous intrauterine insemination; and 9 (8%) had previous assisted reproductive technology. The cumulative adjusted proportion of first live births for those completing up to 24 months of NPT treatment was 66 per 100 couples, and the crude proportion was 38%. The cumulative adjusted proportion of first conceptions was 73 per 100 couples, and the crude proportion was 47%. Of the 51 couples who conceived, 12 couples (24%) conceived with CrMS instruction alone, 35 (69%) conceived with CrMS and NPT medical treatment, and 4 (8%) conceived after additional surgical treatment. All births were singleton births; 54% were born at 37 weeks' gestation or later; and 78% had birth weights of 2500 g or greater.
Conclusion:
Natural procreative technology in a family physician's office was effective in treating infertility and miscarriage with outcomes that were comparable to those in an NPT general practice in Ireland. Larger multicentre prospective studies to compare NPT directly to other forms of infertility treatment are warranted.
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