An accurate understanding of the fertile window and timing of ovulation is critical in helping couples time sexual intercourse correctly and improve chances of pregnancy. Fertility charting can greatly reduce the time to conception as well as reduce unnecessary medical intervention and cost.
Understanding the fertile window
Identifying the fertile window involves a thorough understanding of cervical mucous. Cervical mucous is the main biomarker that opens the fertile window. Pregnancy can not occur without the presence of cervical mucous. Cervical mucous helps to nourish and protect the sperm during their journey through the female reproductive tract, it also creates a hospitable environment for the sperm to survive and swim towards the egg. The type of cervical mucous present can either increase or decrease the chances of achieving pregnancy. (You can read more about cervical mucous for fertility here). In some cases improving the quality of cervical mucous may also help increase chances of pregnancy. This is achieved mostly through balancing hormones, you can read more about improving cervical mucous quality for fertility here)
According to the research study by Hampton et al. (2013), around 60% of women believe they can correctly identify their fertile window but in reality only a small number of women (13%) were actually able to do so. Incorrectly identifying the fertile window may lead to missed opportunities for conception, resulting in prolonged time to conception. Another study conducted on 330 women reported that over half of women believed they always ovulated on day 14-15, Less than a third of women could identify peak fertile days correctly and similar to the previous article only around 13% of women were able to identify their ovulation day accurately. Overall, knowledge regarding ovulation, fertility, and conception is limited among most women. Research shows that older women are more prone to believing misconceptions and myths based on the outdated rhythm method or calendar method, and young women generally have very little knowledge about the fertile window and fertility in general. Much of the misunderstandings might be accounted for by the huge rise in period tracking apps which use algorithms to try and predict the fertile window and ovulation. Most period tracking app algorithms are based on the rhythm method which can not correctly predict the fertile window or ovulation. (You can read more about period tracking apps here)
To use fertility awareness methods to achieve pregnancy, couples need to chart the woman’s menstrual cycle carefully through Fertility Awareness Method (FAM) or fertility charting. This involves keeping a record of the length of the menstrual cycle, the first day of each period, and any changes in cervical mucus and basal body temperature. For women with regular cycles, the fertile window usually lasts for about six days, starting five days before ovulation and ending on the day of ovulation. The timing of ovulation can change every month, even for women with regular cycles. For women with irregular cycles, detecting the fertile window can be challenging, especially when there are multiple days of fertile/peak cervical mucus. When charting with irregular cycles or multiple days of fertile/peak mucous, it is important to treat each day of observed mucous as potentially fertile. There is no way of knowing when the body will actually ovulate and so it is important to chart in real time and assume fertility. This can be frustrating if attempting to conceive as the timing of intercourse to coincide with ovulation is very hard to predict.
How to time intercourse for maximum chances of pregnancy
Studies have shown that the chances of pregnancy vary throughout the menstrual cycle. While the fertile window typically lasts for up to six days, the highest chance of pregnancy occurs during the three days leading up to and including ovulation. During this time, the chance of pregnancy can be as high as 30% per cycle for couples who are actively trying to conceive. Although sperm can live up to 6 days within the female reproductive tract, the vast majority of sperm only live around 3 days so timing of intercourse as close as possible to ovulation is ideal. Outside of the fertile window, the chances of pregnancy are close to zero. One way to help narrow down the fertile window further is to use ovulation predictor kits (OPKs). These are urine tests that detect the surge of luteinizing hormone (LH) that occurs 24 to 48 hours before ovulation. By using OPKs, couples can more accurately pinpoint when ovulation is about to occur and increase their chances of conception by timing intercourse accordingly. However, it’s important to note that OPKs are not foolproof, and they may not work for everyone. Additionally, they can be expensive and may cause unnecessary stress if relied upon too heavily. It’s also essential to use OPKs in conjunction with other fertility awareness methods to ensure the most accurate results. You can read more about OPK’s here.
How often should couples have sex during the fertile window?
During the fertile window (the period of time when fertile cervical mucous is observed) couples should aim to have intercourse at least every second day to increase the chances of sperm being present when the egg is released. It was once believed that having sexual intercourse daily would lower the quantity and quality of the sperm and therefore lower the chances of achieving pregnancy. Currently the evidence to support this theory is mixed but generally not supportive of this idea. Some sperm parameters improve with prolonged abstinence while other parameters improve with more frequent ejaculation. Couples are advised to have sex as often as they feel comfortable in the fertile window. For the majority of couples, daily sex does not increase chances of pregnancy and is exhausting, therefore most experts are advising sexual intercourse every second day within the fertile window for the best chances of achieving pregnancy in the most sustainable way.
Fertility charting can significantly reduce time to conception for many couples as well as potentially reduce unnecessary medical intervention and cost. However, despite correctly timing intercourse during the fertile window, pregnancy may not be achieved for various reasons. For example, age-related factors, such as decreased egg quality or quantity, can impact fertility. Health conditions, such as endometriosis or polycystic ovary syndrome (PCOS), may also affect fertility. Lifestyle factors, including stress, smoking, and excessive alcohol consumption, can further impact the chances of achieving pregnancy. In these cases it may be necessary to make changes to diet and lifestyle to help support and improve fertility for both men and women. Seeking medical guidance may be necessary alongside charting the menstrual cycle for conception.
Hampton, K. D., Mazza, D., & Newton, J. M. (2013). Fertility-awareness knowledge, attitudes, and practices of women seeking fertility assistance. Journal of advanced nursing, 69(5), 1076–1084. https://doi.org/10.1111/j.1365-2648.2012.06095.x
Hanson, B. M., Aston, K. I., Jenkins, T. G., Carrell, D. T., & Hotaling, J. M. (2018). The impact of ejaculatory abstinence on semen analysis parameters: a systematic review. Journal of assisted reproduction and genetics, 35(2), 213–220. https://doi.org/10.1007/s10815-017-1086-0
Lundsberg, L. S., Pal, L., Gariepy, A. M., Xu, X., Chu, M. C., & Illuzzi, J. L. (2014). Knowledge, attitudes, and practices regarding conception and fertility: a population-based survey among reproductive-age United States women. Fertility and sterility, 101(3), 767–774. https://doi.org/10.1016/j.fertnstert.2013.12.006
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Wilcox, A. J., Dunson, D., & Baird, D. D. (2000). The timing of the “fertile window” in the menstrual cycle: day specific estimates from a prospective study. BMJ (Clinical research ed.), 321(7271), 1259–1262. https://doi.org/10.1136/bmj.321.7271.1259
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