Arevalo, M.; Jennings, V.; Nikula, M.; Sinai, I., Efficacy of the new TwoDay Method of family planning. Fertil Steril 2004, 82 (4), 885-92.
PubMed | Article

Arevalo, M.; Jennings, V.; Sinai, I., Efficacy of a new method of family planning: the Standard Days Method. Contraception 2002, 65 (5), 333-8.
PubMed | Article

Bhargava, H.; Bhatia, J. C.; Ramachandran, L.; Rohatgi, P.; Sinha, A., Field trial of billings ovulation method of natural family planning. Contraception 1996, 53 (2), 69-74.
PubMed

Fehring, R. J.; Schneider, M.; Raviele, K.; Barron, M. L., Efficacy of cervical mucus observations plus electronic hormonal fertility monitoring as a method of natural family planning. J Obstet Gynecol Neonatal Nurs 2007, 36 (2), 152-60.
PubMed

Fehring, R.J., Schneider, M., Raviele, K., Rodriguez, D., Pruszynski, J. Randomized comparison of two Internet-supported fertility-awareness-based methods of family planning, Contraception 2013, 88(1), 24-30.
PubMed

Fehring, R., Lawrence, D., Philpot, C. Use effectiveness of the Creighton model ovulation method of natural family planning, J Obstet Gynecol Neonatal Nurs 1994, 23(4), 303-312.
PubMed | Article

Fehring, R.J., Schneider, M., Barron, M.L., Prezsynski, J. Influence of motivation on the efficacy of natural family planning, Am J Mat Child Nursing 2013, 38(6):352-8.
PubMed | Article

Frank-Herrmann, P.; Freundl, G.; Gnoth, C.; Godehardt, E.; Kunert, J.; Baur, S.; Sottong, U., Natural family planning with and without barrier method use in the fertile phase: efficacy in relation to sexual behavior: a German prospective long-term study. Adv Contracept 1997, 13 (2-3), 179-89.
PubMed

Frank-Herrmann, P.; Heil, J.; Gnoth, C.; Toledo, E.; Baur, S.; Pyper, C.; Jenetzky, E.; Strowitzki, T.; Freundl, G., The effectiveness of a fertility awareness based method to avoid pregnancy in relation to a couple’s sexual behaviour during the fertile time: a prospective longitudinal study. Hum Reprod 2007, 22 (5), 1310-9.
PubMed | Article

Gnoth, C.; Godehardt, D.; Godehardt, E.; Frank-Herrmann, P.; Freundl, G., Time to pregnancy: results of the German prospective study and impact on the management of infertility. Hum Reprod 2003, 18 (9), 1959-66.
PubMed | Article

Hilgers, T. W.; Daly, K. D.; Prebil, A. M.; Hilgers, S. K., Cumulative pregnancy rates in patients with apparently normal fertility and fertility-focused intercourse. J Reprod Med 1992, 37(10), 864-6.
PubMed

Hilgers, T. W.; Stanford, J. B., Creighton Model NaProEducation Technology for avoiding pregnancy. Use effectiveness. J Reprod Med 1998, 43 (6), 495-502.
PubMed

Howard, M. P.; Stanford, J. B., Pregnancy probabilities during use of the Creighton Model Fertility Care System. Arch Fam Med 1999, 8 (5), 391-402.
PubMed | Article

Lamprecht, V.; Trussell, J., Natural family planning effectiveness: evaluating published reports. Adv Contracept 1997, 13 (2-3), 155-65.
PubMed

Manhart, M.D., Duane, M., Linda, A., Sinai, I., Golden-Tevald, J. Fertility awareness-based methods of family planning: A review of effectiveness for avoiding pregnancy using SORT, Osteopathic Family Physician 2013, 5(1), 2-8.
Abstract | Article

Robinson, J. E.; Wakelin, M.; Ellis, J. E., Increased pregnancy rate with use of the Clearblue Easy Fertility Monitor. Fertil Steril 2007, 87 (2), 329-34.
PubMed

Sinai, I.; Cachan, J., A Bridge for postpartum women to Standard Days Method(R): II. Efficacy study. Contraception 2012, 86 (1), 16-21.
PubMed

Sinai, I.; Jennings, V.; Arévalo, M., The importance of screening and monitoring: the Standard Days Method and cycle regularity. Contraception 2004, 69 (3), 201-6.
PubMed | Article

Stanford, J. B.; Parnell, T. A.; Boyle, P. C., Outcomes from treatment of infertility with natural procreative technology in an Irish general practice. J Am Board Fam Med 2008, 21 (5), 375-84.
PubMed | Article

Tham, E.; Schliep, K.; Stanford, J., Natural procreative technology for infertility and recurrent miscarriage: outcomes in a Canadian family practice. Can Fam Physician 2012, 58 (5), e267-74.
PubMed | Article

Trussell, J.; Grummer-Strawn, L., Contraceptive failure of the ovulation method of periodic abstinence. Fam Plann Perspect 1990, 22 (2), 65-75.
PubMed

Trussell, J.; Grummer-Strawn, L., Further analysis of contraceptive failure of the ovulation method. Am J Obstet Gynecol 1991, 165 (6 Pt 2), 2054-9.
PubMed

Warniment, C. B.; Hansen, K., Is natural family planning a highly effective method of birth control? Yes: natural family planning is highly effective and fulfilling. Am Fam Physician 2012, 86 (10), 1-2.
PubMed | Article

[World Health Organization] A prospective multicentre trial of the ovulation method of natural family planning. II. The effectiveness phase. Fertil Steril 1981, 36 (5), 591-8.
PubMed

American Academy of Pediatrics Committee on Adolescence, American College of Obstetricians and Gynecologists Committee on Adolescent Health Care, Diaz, A., Laufer, M.R., Breech, L.L. Clinical report: Menstruation in girls and adolescents: Using the menstrual cycle as a vital sign. Pediatrics, 2006, 118(5), 2245-2250.
PubMed | Article

Cohen, M. R.; Stein, I. F., Sr.; Kaye, B. M., Spinnbarkeit: a characteristic of cervical mucus; significance at ovulation time. Fertil Steril 1952, 3 (3), 201-9.
PubMed

Vigil, P., Ceric, F., Cortes, M.E., Klaus, H. Usefulness of monitoring fertility from menarche. J Ped and Adol Gynecology 2006, 19, 172-179.
PubMed 

Wilcox, A. J.; Weinberg, C. R.; Baird, D. D., Post-ovulatory ageing of the human oocyte and embryo failure. Hum Reprod 1998, 13 (2), 394-7.
PubMed | Article

Wilcox, A. J.; Weinberg, C. R.; Baird, D. D., Timing of sexual intercourse in relation to ovulation. Effects on the probability of conception, survival of the pregnancy, and sex of the baby.N Engl J Med 1995, 333 (23), 1517-21.
PubMed | Article

Cibula, D.; Gompel, A.; Mueck, A. O.; La Vecchia, C.; Hannaford, P. C.; Skouby, S. O.; Zikan, M.; Dusek, L., Hormonal contraception and risk of cancer. Hum Reprod Update 2010, 16 (6), 631-50.
PubMed

Gnoth, C.; Frank-Herrmann, P.; Schmoll, A.; Godehardt, E.; Freundl, G., Cycle characteristics after discontinuation of oral contraceptives. Gynecol Endocrinol 2002, 16 (4), 307-17.
PubMed

Higgins, J. E.; Wilkens, L. R., Statistical comparison of Pearl rates. Am J Obstet Gynecol 1985, 151 (5), 656-9.
PubMed

Kahlenborn, C.; Stanford, J. B.; Larimore, W. L., Postfertilization effect of hormonal emergency contraception. Ann Pharmacother 2002, 36 (3), 465-70.
PubMed | Article

Heffron, R.; Donnell, D.; Rees, H.; Celum, C.; Mugo, N.; Were, E.; de Bruyn, G.; Nakku-Joloba, E.; Ngure, K.; Kiarie, J.; Coombs, R. W.; Baeten, J. M., Use of hormonal contraceptives and risk of HIV-1 transmission: a prospective cohort study. Lancet Infect Dis 2012, 12 (1), 19-26.
PubMed | Article

Morrison, C. S.; Nanda, K., Hormonal contraception and HIV: an unanswered question. Lancet Infect Dis 2012, 12 (1), 2-3.
PubMed | Article

Morrison, C. S.; Bright, P.; Wong, E. L.; Kwok, C.; Yacobson, I.; Gaydos, C. A.; Tucker, H. T.; Blumenthal, P. D., Hormonal contraceptive use, cervical ectopy, and the acquisition of cervical infections. Sex Transm Dis 2004, 31 (9), 561-7.
PubMed | Article

Mosher, W. D.; Martinez, G. M.; Chandra, A.; Abma, J. C.; Willson, S. J., Use of contraception and use of family planning services in the United States: 1982-2002. Adv Data 2004, (350), 1-36.
PubMed | Article

Stanford, J. B.; Larimore, W., Informed consent for postfertilization effects of hormonal and surgical forms of birth control for women. Arch Fam Med 2000, 9 (8), 690-1.
PubMed

Wilcox A. J., Baird D. B., Weinberg C. R., Time of implantation of the conceptus and loss of pregnancy. N Engl J Med 1999, 340, 1796-9.
PubMed | Article