Optimizing natural fertility: a committee opinion Practice Committee of the American Society for Reproductive Medicine in collaboration with the Society for Reproductive Endocrinology and Infertility American Society for Reproductive Medicine, Birmingham, Alabama This Committee Opinion provides practitioners with suggestions for optimizing the likelihood of achieving pregnancy in couples/ individuals attempting conception who have no evidence of infertility. This document replaces the document of the same name previously published in 2013, Fertil Steril 2013;100(3):631-7. (Fertil SterilÒ 2017;107:52–8. Ó2016 by American Society for Repro- ductive Medicine.) Earn online CME credit related to this document at www.asrm.org/elearn Discuss: You can discuss this article with its authors and with other ASRM members at https://www.fertstertdialog.com/users/ 16110-fertility-and-sterility/posts/12118-23075 linicians may be asked to pro- fecundability (the probability of preg- FREQUENCY OF vide advice about sexual and nancy per month) is greatest in the first INTERCOURSE lifestyle practices relating to 3 months (1). Relative fertility is C In some cases, clinicians may need to procreation. Currently, there are no decreased by about half among women explain the basics of the reproductive uniform counseling guidelines or in their late 30s compared with women process. Information has emerged over evidence-based recommendations in their early 20s (2, 3). the last decade that, at least in theory, available. This document will provide Fertility varies among populations may help to define an optimal fre- practitioners with recommendations, and declines with age in both men quency of intercourse. Whereas absti- based on a consensus of expert opinion, and women, but the effects of age are nence intervals greater than 5 days for counseling couples/individuals much more pronounced in women may adversely affect sperm counts, about how they might optimize the (2, 4) (Fig. 1). For women, the chance abstinence intervals as short as 2 days likelihood of achieving pregnancy of conception decreases significantly are associated with normal sperm den- when there is no history of infertility after age 35 (5). Although semen sities (7). A widely held misperception is or reason to question their potential parameters in men also decline that frequent ejaculations decrease fertility. detectably after 35 years of age, male male fertility. A retrospective study fertility does not appear to be affected that analyzed almost 10,000 semen FERTILITY AND AGING before approximately age 50 (4). specimens observed that, in men with Fertility is defined as the capacity to Infertility is a disease, defined as normal semen quality, sperm concen- produce a child. Whereas the likelihood the failure to achieve a successful preg- trations and motility remain normal, of conception remains relatively stable nancy after 12 months or more of regu- even with daily ejaculation (8). Surpris- from cycle to cycle within individuals, lar unprotected intercourse or exposure ingly, in men with oligozoospermia, it generally is highest in the first to sperm (6). Earlier evaluation and sperm concentration and motility may months of unprotected intercourse or treatment may be justified based on be highest with daily ejaculation (8). exposure to sperm and declines gradu- medical history and physical findings Abstinence intervals generally also do ally thereafter in the population as a and is warranted after 6 months not appear to affect sperm morphology, whole (1). Approximately 80% of cou- without conception for women over as judged by ‘‘strict’’ criteria (9). How- ples will conceive in the first 6 months age 35 years due to the age-related ever, after longer abstinence intervals of attempting pregnancy (1). Monthly decline in fertility (6). of 10 days or more, semen parameters begin to deteriorate. Although studies of semen parameters provide useful Received September 13, 2016; accepted September 13, 2016; published online October 26, 2016. quantitative data, those data may not Reprint requests: Practice Committee, American Society for Reproductive Medicine, 1209 Montgomery Hwy, Birmingham, Alabama 35216 (E-mail: [email protected]). accurately predict the functional integ- rity or capacity of sperm. Fertility and Sterility® Vol. 107, No. 1, January 2017 0015-0282/$36.00 Copyright ©2016 American Society for Reproductive Medicine, Published by Elsevier Inc. Although evidence suggests that http://dx.doi.org/10.1016/j.fertnstert.2016.09.029 daily intercourse may confer a slight 52 VOL. 107 NO. 1 / JANUARY 2017 Fertility and Sterility® fecundability was observed when intercourse occurred within FIGURE 1 2 days prior to ovulation (10) (Fig. 2). In another family plan- ning study, investigators combined data obtained from two cohorts, one using basal body temperature monitoring and the other using analysis of urinary estrogen/progesterone me- tabolites, to determine the likely time of ovulation; the likeli- hood of pregnancy was greatest when intercourse occurred the day prior to ovulation and started to decline on the day of presumed ovulation (14). Among women who described their menstrual cycles as ‘‘generally regular,’’ the likelihood of conception resulting from a single act of intercourse increases during the putative fertile window (15). The probability of clinical pregnancy increased from 3.2% on cycle day 8 to 9.4% by day 12 and decreased to less than 2% by cycle day 21. Whereas aging generally does not affect the size or nature of the fertile window, the likelihood of success decreases with increasing age (Fig. 3). Pregnancy rate (per 1,000 women) in various populations at different In addition, cycle fecundability increases with the frequency of times in history. Modified from Menken et al. (4). The 10 populations intercourse during the fertile window (16). Accurately predict- (in descending order at age 20 to 24) are Hutterites, marriages 1921– 30 (solid triangles); Geneva bourgeoisie, husbands born 1600–49 ing ovulation can be challenging with any available method. (solid squares); Canada, marriages 1700–30 (solid circles); As a consequence, the likelihood of conception can be maxi- Normandy, marriages 1760–90 (open circles); Hutterites, marriages mized by increasing the frequency of intercourse beginning – before 1921 (open squares); Tunis, marriages of Europeans 1840 soon after cessation of menses and continuing to ovulation in 59 (open triangles); Normandy, marriages 1674–1742 (solid circles); Norway, marriages 1874–76 (open squares); Iran, village marriages, women having regular menstrual cycles. The length of the 1940–50 (solid triangles); Geneva bourgeoisie, husbands born fertile window may vary among women, altering the likelihood before 1600 (open circles). of success (17). As a result, regular intercourse to optimize cycle ASRM. Optimizing natural fertility. Fertil Steril 2016. fecundity should be recommended. advantage, specific recommendations regarding the fre- MONITORING OVULATION quency of intercourse may unnecessarily induce stress. In The time of peak fertility can vary considerably, even among one study involving 221 presumably fertile couples planning women who have regular cycles. Women who monitor their to conceive, the highest cycle fecundability (37% per cycle) cycles and track changes in cervical mucus, libido, pain, or was associated with daily intercourse (10). Intercourse on mood are able to predict ovulation accurately no more than alternate days yielded a comparable pregnancy rate per cycle 50% of the time (18). Although there is no substantial evi- (33%), but the likelihood for success decreased to 15% per cy- dence that monitoring by this or other methods increases cy- cle when intercourse occurred only once weekly (10). The cle fecundability, a common perception is that the timing of stress associated with trying to conceive can reduce sexual intercourse is crucial and therefore should be determined by esteem, satisfaction, and the frequency of intercourse (11). These parameters are further aggravated when the timing of intercourse is linked to ovulation predictor methods or fol- FIGURE 2 lows a strict schedule (12). Couples should be informed that reproductive efficiency increases with the frequency of inter- course and is highest when intercourse occurs every 1 to 2 days, but be advised that the optimal frequency of inter- course is best defined by their own preference within that context. THE FERTILE WINDOW For counseling purposes, the ‘‘fertile window’’ is best defined as the 6-day interval ending on the day of ovulation (10, 13). At least in theory, the viability of both oocytes and sperm should be maximal during that time. For clinical purposes, the interval of maximum fertility can be estimated by analysis of intermenstrual intervals, ovulation predictor kits, or cervical mucus scores. Intercourse is most likely to result in pregnancy when it Probability of pregnancy with a single act of intercourse. Modified occurs within the 3-day interval ending on the day of ovula- from Dunson et al. (14). tion. In the study involving 221 presumed fertile women, peak ASRM. Optimizing natural fertility. Fertil Steril 2016. VOL. 107 NO. 1 / JANUARY 2017 53 ASRM PAGES before or after the peak (21). A prospective study including FIGURE 3 2,832 cycles observed that changes in cervical mucus charac- teristics correlate closely with basal body temperature and 0.6 19-26yo 35-39yo predict the time of peak fertility more accurately than a men- c n 0.5 strual calendar (22). a n g e Ovulation detection devices, including kits for moni- r P 0.4 f o toring urinary luteinizing hormone (LH) excretion and elec- y t i l i b tronic monitors, are promoted widely as tools that can help a 0.3 b o ‘‘ ’’ r couples to determine their fertile time (23). There is some P c i f 0.2 i evidence to suggest that LH detection kits may underestimate c e p S the fertile window (24). Although numerous studies have vali- 0.1 Day- y dated the accuracy of methods for detecting the midcycle uri- nary LH surge (25–27), ovulation may occur anytime within 0 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 the 2 days thereafter (27, 28), and false-positive test results Day Relative to Ovulation occur in approximately 7% of cycles (29).