To evaluate pregnancy probabilities during use of the Creighton Model Fertility Care System (CrMS).
Design
Couples who began use of the CrMS were entered into this observational cohort study. Follow-up included detailed reviews of use of the CrMS. Pregnancy probabilities were calculated with both net and gross life-table analysis through 18 months.
Setting
A natural family planning service delivery program based at an urban hospital in Houston, Tex.
Subjects
A group of 701 couples who received instruction in the CrMS were entered into the study. Most couples (93%) were engaged or married. Most women were white (83%), between the ages of 20 and 34 years (88%), and college graduates (58%).
Main Outcome Measure
Pregnancies were classified based on a detailed evaluation involving the pregnant woman (usually with her partner).
Results
At 12 months, the following net pregnancy probabilities were found per 100 couples: method-related pregnancies, 0.14; pregnancies caused by user and/or teacher error, 2.72; pregnancies caused by achieving-related behavior (genital contact during a time known to be fertile), 12.84; unresolved pregnancies, 1.43; and total pregnancies, 17.12. Pregnancy probabilities were similar when stratified by the following reproductive categories: uncomplicated regular cycles, long cycles, discontinuing oral contraceptives, breastfeeding, and other.
Conclusions
Pregnancy probabilities of the CrMS compare favorably with those of other methods of family planning. Most pregnancies result from genital contact during a known fertile time. Women need not have regular cycles to use the CrMS successfully.
Creighton Model Fertility Care System pregnancy probabilities, CrMS effectiveness natural family planning cohort study, Howard Stanford Creighton Model pregnancy rates, natural family planning method effectiveness life table analysis, Creighton Model irregular cycles breastfeeding effectiveness, fertility awareness based method unintended pregnancy rates, Creighton Model user error achieving related behavior pregnancy, natural family planning discontinuing oral contraceptives effectiveness, CrMS method related pregnancy probability 12 months, Creighton Model FertilityCare cervical mucus method outcomes
PMID 10500511 10500511 DOI 10.1001/archfami.8.5.391 10.1001/archfami.8.5.391 Howard et al. 1999, Howard 1999
Cite this article
Howard, M. P., & Stanford, J. B. (1999). Pregnancy probabilities during use of the Creighton Model Fertility Care System. Archives of family medicine, 8(5), 391-402. https://doi.org/10.1001/archfami.8.5.391
Howard MP, Stanford JB. Pregnancy probabilities during use of the Creighton Model Fertility Care System. Arch Fam Med. 1999;8(5):391-402. doi:10.1001/archfami.8.5.391
Howard, M. P., and J. B. Stanford. "Pregnancy probabilities during use of the Creighton Model Fertility Care System." Archives of family medicine, vol. 8, no. 5, 1999, pp. 391-402.
Keywords
Adolescent, Adult, Family Planning Services, Female, Hospitals, Urban, Humans, Life Tables, Male, Pregnancy, Probability, Texas
Knowledge of the fertile and infertile phases of the menstrual cycle can be applied to conceive or to avoid pregnancy. Fertility intentions and sexual behaviors during the fertile time may influence whether and when pregnancy occurs. The Creighton Model FertilityCare System (CrMS) is a specific system of fertility appreciation used to conceive or to avoid pregnancy. The objective of this paper is to report intentions, behaviors, and pregnancy rates during use of the CrMS among couples who initially intended to avoid pregnancy.Data and methodsWe analyzed a prospective cohort study conducted in 17 CrMS centers across the USA and Canada, following 296 couples for up to one year after onset of initial use of the CrMS to avoid pregnancy. Baseline data included demographics, motivations, and pregnancy intentions for each partner. Couples contributed 2894 menstrual cycles, most of which had data collected (by questionnaires and daily diary) on cycle-specific pregnancy intentions, days of potential fertility, and fertility behaviors. Pregnancies were prospectively actively ascertained. We found a high concordance (91%) in cycle pregnancy intentions between partners. However, 44% of cycles with strong intentions to avoid pregnancy included intercourse on potentially fertile days or days of undetermined fertility status. Across all sensitivity scenarios, cumulative 13-cycle pregnancy rates with cycle intention to conceive ranged from 88.0% to 89.8%, and cumulative 13-cycle pregnancy rates with cycle intention to avoid ranged from 29.1% to 35.3%. In multivariate analysis, baseline motivations and intentions for pregnancy within 2 years were strongly correlated with the likelihood of pregnancy, more so than cycle intentions. The findings suggest that in some populations using natural family planning, baseline motivations and intentions may be more strongly related to pregnancy rates than cycle intentions. Our findings also highlight essential elements for evaluating correct use, including complete recording of intercourse and its timing.
Horodenchuk Z et al., 2020·Kwartalnik Naukowy Fides et Ratio
To assess the outcomes of treatment the couples with infertility or recurrent miscarriage with restorative reproductive approach and to identify predictors of success. It was a retrospective study of 282 married couples, who were included in the program in 2 outpatient gynaecological centers in May 2010 - December 2014. The couples were observed to the end of pregnancy (or pregnancies) or withdrawal from the program. All the couples were taught to track the cycle with the Creighton Model FertilityCare System or the sympto-thermal method, and almost all received additional medical treatment. The main outcome was live birth, the secondary outcomes included conceptions, unsuccessful pregnancies, low birth weight and prematurity. In life-table analysis, the adjusted cumulative proportion of first conceptions for those completing up to 24 months of NPT treatment was 77.7% (crude proportion 47.9%). The adjusted cumulative proportion of live births was 73.6% (117 births, crude proportion 41.5%). Mean time to achieving pregnancy was 8 months. All the births except one were singleton. There were only 3 preterm births. The favorable predictors of live birth were younger age, shorter time of trying for baby, good compliance, pregnancy in history. The unfavorable were hyperprolactinemia, uterine fibroids, endometriosis, male factor. The outcomes of restorative reproductive treatment the couples with infertility or recurrent miscarriage in Ukraine were comparable to those in Ireland and Canada.
We evaluated outcomes in couples treated for infertility with natural procreative technology (NaProTechnology [corrected] NPT), a systematic medical approach for optimizing physiologic conditions for conception in vivo, from an Irish general practice. All couples receiving treatment from 2 NPT-trained family physicians between February 1998 and January 2002 were studied. The main outcome was live birth, and secondary outcomes included conceptions and multiple births. Crude proportions and adjusted life-table proportions were calculated per 100 couples. A total of 1239 couples had an initial consult for NPT, of which 1072 had been trying for at least a year to conceive and initiated treatment. The average female age was 35.8 years, the mean duration of attempting to conceive was 5.6 years, 24% had a prior birth, and 33% had previously attempted treatment with assisted reproductive technology (ART). All couples were taught to identify the fertile days of the menstrual cycle with the Creighton Model FertilityCare System, and most received additional medical treatment, including clomiphene (75%). In life-table analysis, the cumulative proportion of first live births for those completing up to 24 months of NPT treatment was 52.8 per 100 couples. The crude proportion was 25.5. Younger couples and couples without previous ART attempts had higher rates of live birth. Among live births, there were 4.6% twin births. NPT provided by trained general practitioners had live birth rates comparable to cohort studies of more invasive treatments, including ART. Further studies are warranted to compare NPT directly to other treatments.
Stanford JB, 2004·The Medical and Surgical Practice of NaProTECHNOLOGY·
Methodologically rigorous effectiveness data for the CrMS are presented, including method-effectiveness and use-effectiveness rates for pregnancy avoidance drawn from prospective cohort studies, demonstrating rates comparable to or exceeding hormonal contraception. Standardized outcome measurement is necessary to establish the CrMS's scientific credibility and to provide practitioners and patients with accurate, evidence-based counseling on system performance.