Fertility Awareness-Based Methods: Another Option for Family Planning

Stephen R. Pallone, MD; George R. Bergus, MD

J Am Board Fam Med. 2009;22(2):147-157.

Symptothermal Method

The Symptothermal Method combines BBT, cervical methods, cervical position, and/or historical cycle data to prospectively and retrospectively identify the peri-ovulatory period. In its most effective form, 2 signs are used to "double check" each phase as confirmation for the couple that the woman is unlikely to be fertile.^[20,26] The method has a 0.4% pregnancy rate when used as described.^[4,14]

Typical-use unplanned pregnancy rates have been reported as low as 1% to 3% in Europe and India.^{[7,12,13,14,15,16,19,20]} However, unplanned pregnancy rates as high as 13% to 20% have also been reported for typical users of the Symptothermal Method.^[4] Critics warn that combining signs and symptoms can overestimate the fertile phases by a couple of days or more. On the other hand, because there is no requirement to abstain every other day before the fertile phase, the total abstinence time is approximately equivalent to cervical secretion methods. There is a trend of increased intercourse among couples who use barrier back-up methods concurrently. This trend, however, may be confounded because women using barrier backup are generally younger.^[49]

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Cite this: Fertility Awareness-Based Methods: Another Option for Family Planning - Medscape - Mar 31, 2009.

Table 1. Conventional Birth Control: Method and User Effectiveness Rates
Method	Women with Unintended Pregnancy Within 1 Year of Use (%)		Women Continuing Use at 1 Year (%)
Method	Typical Use	Perfect Use	Women Continuing Use at 1 Year (%)
None	85	85
Spermicide	29	18	42
Withdrawal	27	4	43
Cervical cap
Parous	32	26	46
Nulliparous	16	9	57
Sponge
Parous	32	20	46
Nulliparous	16	9	57
Diaphragm	16	6	57
Condom
Male	15	2	53
Female	21	5	49
Combined pill and minipill	8	0.3	68
Evra patch	8	0.3	68
NuvaRing	8	0.3	68
Depo-Provera	3	0.3	56
Lunelle	3	0.05	56
Intrauterine device
Copper T	0.8	0.6	78
Mirena	0.1	0.1	81
Norplant and Norplant-2	0.05	0.05	84
Female sterilization	0.5	0.5	100
Male sterilization	0.15	0.10	100

Reproduced with permission from Hatcher R, Trussell J, Stewart F, et al. Contraceptive Technology 18^th ed. Ardent Media, Inc, New York, NY, 2004.^[4]

Table 2. Fertility Awareness-Based Methods Based on Life Table Analysis ^{[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35]}
Method	Women with Unintended Pregnancy Within 1 Year of Use (%)			Women Continuing Use at 1 Year (%)	Women with Unintended Pregnancy Caused by Unprotected Intercourse on Days Known Fertile Days (%)
Method	Typical Use	With Barrier Backup^*	Perfect Use	Women Continuing Use at 1 Year (%)
Calendar
Rhythm^†	25		0.1-9
Standard days^‡	12	5.7	4.8	46^§	7.8
Basal body temperature			1
Cervical mucous
TwoDays	13.7	6.3	3.5	52.7^\|\|	7.3
Billings Ovulation^¶	10.5-22.3	NT	0.5	30.4-99.5	15.4
Creighton/NaProEducation Technology	17.1^**	NT	0.5	79.8-88.7	12.8
Symptothermal^¶	0.2-20^††	0.45-2.3^*	0.3	51.7-92.5	8.96
Lactational amennorrhea^‡‡			2	NA	NA

^* Fertility awareness-based methods defined more specifically as natural family planning do not report this data because it is considered abandonment of the method. Data is included where available.
^† Estimated (definitive data not available).
^‡ Limited to women with <2 cycles in 1 year outside of the 26- to 32-day range.
^§ Twenty-eight percent discontinued because of 2 cycles outside 26- to 32-day range or 1 cycle longer than 42 days.
^|| Because of secretions >14 days or cycles <5 days (these are indicators of other potential health concerns), 15.7% asked to leave by study protocol. This loss also included women with cycles >42 days (n = 30) because of the cost of follow-up as well as women who failed to log symptoms for at least 12 cycles (n = 12).
^¶ Typical use variable by study. More recent international studies show progressively lower unintended pregnancy rates and higher continuation rates.
^** Overall pregnancy rate. Studies included women wishing to achieve pregnancy and made no attempt to distinguish planned vs unplanned pregnancies. Pregnancies resulting from intercourse on days known to the couple as fertile were counted as achieving related. Avoiding related pregnancies were 3.2% overall.
^†† Lower typical failure rate with double-check method compared with single-check method.
^‡‡ Perfect-use rate is for first 6 months only. LAM is ineffective as birth control if not used properly.
NT = not taught; NA = not applicable; LAM = Lactational Amennorrhea Method.

Table 3. Percentage of Original Study Group Discontinuing Various Fertility Awareness-Based Methods at 12 Months or 13 Cycles by Study ^[6,10,11,21]
Reason	SDM (%)	TDM (%)	CrM (%)	BOM (%)
Completed study	45.6	52.7	-	-
Eliminated by study protocol	28.0	15.7	-	-
Told risk of pregnancy would be high	0.2	-	-	-
Did not like the method	0.2	1.8	0.7	-
Did not trust the method	1.7	1.8	0.7	-
Partner did not like the method	2.1	2.0	0.7	3.0^*
Planning pregnancy	2.1	2.2	-	5.0^*
To use other FABM	-	-	0.7	-
To use artificial method	-	-	4.5	20.1^*
Difficulty avoiding genital contact	-	-	0.7	-
Other voluntary reason	4.0	10.4	4.6	1.0^*
Lost to follow up	7.1	4.4	-	16.3^*
Pregnancy	9.0	10.4	-^†	16.0^*
Medically induced infertility	-	-	0.3	-
Unknown	-	0.2	-	-

Data not reliably available for Rhythm, Basal Body Temperature, and Symptothermal methods.
^* Billings Ovulation Method-India trial: data reported at 21 ordinal months. Overall discontinuation rate at 12 months was 24%. Individual reasons were not reported for this time frame.
^† Creighton Model did not remove participants from study for pregnancy because studies were designed to evaluate both pregnancy-achieving and pregnancy-avoiding behaviors.
SDM = Standard Days Method; TDM = TwoDays Method; CrM = Creighton Model; BOM = Billings Ovulation Method; - = data not available.

Table 4. Educational and Instructional Resources for Fertility Awareness-Based Methods ^[69]
Organization	Website	Book/Home/Online Course	Method
Georgetown Institute of Reproductive Health	http://www.irh.org	Refer to website	Standard Days and TwoDays Methods
Couple to Couple League International	http://ccli.org	The CCL Home Study Course, ∼$75	Symptothermal Method
The Billings Ovulation Method Association	http://www.boma-usa.org	The Billings Method, ∼$20	Billings Ovulation Method
American Academy of FertilityCare Professionals	http://www.aafcp.org	Refer to website	Creighton Model
One More Soul	http://www.omsoul.com		Search for providers of multiple methods
Marquette University Institute for Natural Family Planning	http://www.marquette.edu/nursing/NFP/Model.shtml		Marquette Model^*
Northwest Family Services	http://www.nwfs.org/nfp.htm	Refer to website	Symptothermal Method^*
Family of the Americas Foundation	http://www.familyplanning.net		Ovulation Method^*

Information from reference cited above and indicated websites.
^* Not specifically discussed in the text.
CCL, Couple to Couple League.

Sidebar: Key Recommendations for Practice

Clinical Recommendation	Evidence Rating	References
Modern FABMs of family planning have similar unintended pregnancy rates in self-selected users compared with other conventional methods.	B	[4-17,20,21,27-34]
Couples interested in using FABMs of family planning should be referred to an instructor certified in the patient's method of choice for adequate instruction.	C	[4-17,20,21,27-34]
Frequency of intercourse is not decreased among couples using the modern FABMs of TwoDays and Standard Days methods compared with those using conventional family planning methods.	B	[58]
Women who are physically separated from or lack the support of their male partner are less likely to use the methods properly and more likely to discontinue use of an FABM.	C	[17]

FABM = fertility awareness-based method.

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