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MonroesMisfit
member
Sex During Fertile Window Study....Very Interersting.
MonroesMisfit
member
Ok ladies, so I have heard so many different things about how often to have sex, and I see percentages etc about it, but since I currently have access (thanks to college, good for something lol) to online journals I thought I would see what was out there...I found this study on couples and it had a LOT of interesting stuff in it...it is rather long but if you are up for a read I recommend it!
Results
Probability of Conception around the Time of Ovulation
The couples in this study had intercourse an average of once every three days, a frequency that makes it difficult in most pregnancies to attribute conception to intercourse on one particular day. As a preliminary exploration, we selected all 192 cycles in which conception occurred and examined the patterns of intercourse around ovulation to identify the range of fertile days. In every cycle in which conception occurred, there was intercourse at least once during the six consecutive days that ended with the day of ovulation. There was no shorter span of days that included intercourse in every cycle. Conversely, there were 31 cycles (of a total of 625) in which there was no intercourse during this six-day interval, and none resulted in conception.
As a preliminary estimate of the chance of conception on individual days, we identified all the cycles in which intercourse occurred on only a single day during the six-day period. On the basis of these 129 cycles (21 percent of the total), the proportion with a detected pregnancy ranged from 0.08 on the first day of the six-day period to 0.36 on the sixth day (the day of ovulation) (Figure 2Figure 2
Probability of Conception on Specific Days near the Day of Ovulation.).
For all 625 cycles, we applied our statistical model to estimate the chance of conception on each of the six days in the fertile period. These probabilities ranged from 0.10 to 0.33 ? figures similar to the proportions for the single-day cycles (Figure 2). Standard errors for the estimated probabilities are provided in Table 1Table 1
Probability of Conception Based on 129 Menstrual Cycles in Which Sexual Intercourse Occurred on Only One Day during the Six-Day Interval Ending with the Day of Ovulation and on All 625 Cycles.. The proportion of ovulatory cycles potentially able to produce a pregnancy (cycle viability) was estimated to be 0.37 (95 percent confidence interval, 0.31 to 0.48).
We added one day to the six-day period in each direction and repeated the analysis. The estimated probability of conception was zero on both marginal days. However, we cannot exclude a probability of conception of up to 12 percent on either the seventh day before ovulation or the day after ovulation (95 percent confidence interval, 0 to 0.12).
If the cycle is viable (i.e., if conception is possible), the model assumes that each day of intercourse in the six-day period contributes independently to the probability of pregnancy. Thus, daily intercourse would produce the highest probability of conception (0.37). The estimated rate of conception falls to 0.33 with intercourse that averages every other day (assuming no special timing with regard to ovulation). At lower frequencies of intercourse, the rate of conception drops more rapidly; untimed intercourse averaging once per week would produce a 0.15 chance of conception per cycle. Considering live births only (which accounted for two thirds of the conceptions), the approximate probability would be 0.25 with daily intercourse, 0.22 with intercourse every other day, and 0.10 with weekly intercourse.
The assumption that each day on which intercourse occurs makes an independent contribution to conception is open to question. Frequent intercourse might decrease the potency of semen ? for example, by depleting the number or quality of sperm.21-23 As a rough test of this hypothesis, we sorted cycles according to the number of days on which intercourse occurred during the six-day period. If frequent intercourse decreases the fertilizing capacity of sperm, then the observed number of pregnancies initiated in cycles with more frequent intercourse should be less than that predicted by the combined day-specific probabilities. Similarly, cycles with intercourse on only one day should produce more pregnancies than predicted. Table 2Table 2
Predicted and Observed Numbers of Pregnancies, According to the Number of Days when Sexual Intercourse Occurred during the Six-Day Interval Ending with the Day of Ovulation. shows the predicted and observed numbers of pregnancies for each frequency of intercourse (from none to daily) during the six-day period. The model fits well across the range of values for the frequency of intercourse, with no overall trend toward lower fertility with a higher frequency of intercourse.
Age of Sperm and Survival of the Pregnancy
It has been speculated that fertilization by old sperm (i.e., sperm that remain in the female reproductive tract for a relatively long time before fertilization) produces damaged conceptuses and leads to loss of pregnancy.24 In order to address this question, we arranged cycles during which conception occurred according to the number of days between ovulation and the most recent instance of intercourse; we then divided the conceptions according to whether or not they resulted in live birth. Only 6 percent of the conceptions could be firmly attributed to fertilization by sperm three or more days old. The pattern of intercourse in relation to ovulation was similar overall for conceptions that ended in fetal loss and those that ended in live birth (Figure 3Figure 3
Frequency Distribution of Live Births and Pregnancy Losses, According to the Time of the Most Recent Instance of Sexual Intercourse before Ovulation during the Cycle when Conception Occurred.).
Timing of Intercourse and the Sex of the Baby
Some have argued that the timing of intercourse in relation to ovulation can influence the sex of the conceptus.25 We tested for any association between timing and the sex of the infant by dividing live births according to whether the babies were boys or girls and again plotting the distribution of cycles during which conception occurred according to the day of most recent instance of intercourse (Figure 4Figure 4
Frequency Distribution of Live-Born Boys and Girls, According to the Time of the Most Recent Instance of Sexual Intercourse before Ovulation during the Cycle when Conception Occurred.). There were no systematic differences between the patterns of intercourse that produced boys and the patterns that produced girls.
Discussion
Despite its great practical importance, the number of fertile days during the menstrual cycle has been difficult to specify. Some authors have calculated a theoretical period of two fertile days, based on estimates of the survival of sperm and eggs.1,2 A multicenter study by the World Health Organization estimated that there are 10 presumably fertile days per cycle, on the basis of the characteristics of the cervical mucus.3
Records made by British couples using natural family planning in the 1960s show a 13-day period during which pregnancies were apparently conceived.11 Barrett and Marshall were the first to use these data to estimate a fertile period15; the data were reanalyzed by Schwartz et al. in 198016 and supplemented and reanalyzed by Royston in 1982.11 The day of ovulation was estimated from women's records of their basal body temperatures; this method is subject to considerable error.26 Moreover, the women had been asked to record the days on which intercourse occurred but not days without intercourse. Errors of omission could lead to the misattribution of conception to intercourse on days far from ovulation, a fact that may help explain the very broad fertile period calculated from these data.
Our data suggest that the fertile period lasts about six days and ends on the day of ovulation. The rapid drop in the probability of conception after ovulation suggests a short survival time for ova, or perhaps a change in the cervical mucus after ovulation that obstructs the entry of new sperm. In contrast, the finding that there are five fertile days before ovulation indicates that sperm retain their ability to fertilize an ovum for up to five days in the female reproductive tract. This is consistent with indirect observations regarding the survival of sperm. Motile sperm have been found in the cervical mucus for seven or more days after insemination,27,28 and sperm retain the capacity to fertilize human ova in vitro after five days at room temperature.29
Some couples are advised to maximize their chance of pregnancy by timing their intercourse to coincide with ovulation (for example, using kits to detect the surge of luteinizing hormone). If the probability of conception declines soon after ovulation, couples who abstain from intercourse until they have evidence of ovulation may miss earlier opportunities for conception.
Even with daily intercourse, most ovulatory menstrual cycles (an estimated 63 percent in our study) may be incapable of producing a conception. Factors besides intercourse apparently have a strong role in determining fertility. The model we have used assumes that the probability of a viable cycle is evenly distributed among couples, although couples in fact tend to vary in the proportion of cycles that are viable.30 The probability of conception could be higher or lower for specific couples. In particular, couples who have been trying to conceive for six months or more (longer than the women in our study) will, on average, have lower cycle viability and thus a lower probability of conception.
Frequency of Intercourse and the Probability of Conception
Closely spaced ejaculations reduce the sperm count, the concentration of sperm, and the percentage of sperm that are motile.21-23 Thus, frequent ejaculation could theoretically reduce the potency of subsequent batches of sperm. However, we found scant evidence of this phenomenon in this study. Our data provide no support for a recommendation that normal couples seeking pregnancy should limit the frequency of sexual intercourse.
Age of the Gamete and Survival of the Pregnancy
Some data on animals have suggested that fertilization by aging sperm may decrease the viability of the resulting conceptus.24 Studies in humans provide few data on this issue and little evidence that older sperm cause spontaneous abortions.31,32 We found no evidence for this association in our data, although only 12 conceptions could be attributed to sperm that were more than two days old. The question of the potential harm caused by aging sperm is likely to be resolved only by data from much larger cohort studies. The most informative would be studies of couples trying to avoid pregnancy by natural family planning, since accidental pregnancies among these couples are likely to result from intercourse at the extremes of the fertile interval.24
The fertilization of aging ova (that is, at some extended time after ovulation) may be more harmful to the conceptus than fertilization by aging sperm.24 We cannot evaluate the risk to conceptions involving old ova because no pregnancies in our study could be attributed to intercourse after the day of ovulation.
Timing of Intercourse and the Sex of the Baby
Various claims have been made for methods of selecting the sex of the infant through the deliberate timing of intercourse. Shettles and Rorvik recommend that couples who wish to have a boy should time their intercourse to coincide with ovulation, with up to 85 percent success claimed for the selection of boys and 80 percent for the selection of girls.25 In contrast, Zarutskie et al. concluded in their review of the published literature that if there is any tendency, it is for more females than males to be conceived when coitus occurs close to ovulation.33 We previously reported a possible association between the sex of the baby and the length of the follicular phase.34 However, we found no association between the sex of the baby and the timing of intercourse in relation to ovulation. We conclude that the deliberate timing of intercourse around the day of ovulation has no practical value in sex selection.
In summary, we have described the fertile days of the menstrual cycle for a group of healthy women. By analyzing data on the day of ovulation (identified by means of hormone assays of daily urine specimens) and daily records of sexual intercourse, we found that all conceptions resulted from intercourse that occurred during a six-day interval ending on the day of ovulation. The sex of the baby was not related to the timing of intercourse in relation to ovulation
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Re: Sex During Fertile Window Study....Very Interersting.
Chemical Pregnancy
this. please. sounds like if you BD for 6 days before O your chances are good?
No, it says the best chances are 2 days before O, 1 day before O, and O day. Also, there is no overall trend that more sex causes a decrease in your chances of becoming pregnant (some people are afraid that too much sex will decrease the number of sperm.) So don't hold back around O!
You can click on the graphs to make them larger.
ETA: clarification
Okay, so the particular days that are best for sex are the same ones, for example, that Fertility Friend suggests.
It says more sex does not decrease your chances, but for example, did couples who only had sex ones in that fertile window have less of a chance?
That last point about TTC 6+ seems to me that it's not your personal cycles that are necessarily less viable, just the trend. I don't think I worded that right but YKWIM?
My take on the 6 months was not that it becomes less viable after that point, but that you get to that point because your cycles are less viable than those of other women who get pregnant sooner.
Point 1: Yes.
Point 2: Yes. The chances increased with more sex. Those who had sex 4 days during the fertile window had the highest success rate. Chances decreased for those who had sex more than 4 days, but not significantly enough to make it a trend.
Point 3: Yes. Your own chances do not decrease after 6+ months, but as a group couples who have been trying 6+ months have less success.
YW Sulf
TTC #1 since March 2011
1 medicated TI cycle & 4 clomid IUIs = all BFNs
DS1 born 2/14
TTC #2 since December 2014
May 2015 unassisted BFP ended in m/c at 7wks
April 2016 FET #1 = BFN
June 2016 FET #2 = c/p
August 2016 FET #3 = BFP!
DS2 born 4/17
I'm not sure why I never thought to do it before, I like actual facts and most the things I google are not actual studies...and I have been reading so many all night lol...lots of info out there!
So basically the study found that couples are most sucessful having sex close to when they ovulate and not so much after.
I hope this wasn't a study funded by the government.
BFP 3/17/10 Missed M/C Confirmed 4/12/10
MIF+Unexplained DX Feb 2012: Femara+Trigger+IUI=BFP
Hi Monroes, would you mind posting the citation here in the thread? I'd like to see it as well. Don't worry about the link, just the journal name, author(s), date, etc. would be great. Thanks!
Ha ha ha! I love this PIP. It looks like my sister's dog!
dx: LPD & low progesterone 11/2011
BFP #1 August 23
Started TTC #1: July 2010 DX: PCOS
BFP: 12/5/10 Natural M/C: 12/17/10 (5w6d)
Cycle 10 - 50mg Clomid + TI = BFN
Cycle 11 - 50mg Clomid + IUI converted to TI = BFN
Cycle 12 - 50mg Clomid + IUI #1 = BFN
Cycle 13 - Clomid Break + Charting + Dr. Recommendations = BFN
Cycle 14 - Clomid Break + Charting + meeting with URO (all clear!) = BFP!!
Beta #1 - 105 Beta #2 - 336! 1st U/S (@5w4d)- gest. sac and yolk sac, measuring 5w2d 2nd U/S - 1/16 (will be 8w2d) Stick and grow, little bean! My Ovulation Chart
* Congrats to my girl SarahRuthG on her new baby boy!*