Ovulation Calculator Download
Yvone Rollman
Trying to conceive can be stressful, but some of that stress can be alleviated by tracking your cycle and calculating your ovulation. The Forbes Health ovulation calculator below can help you estimate what days of your cycle might result in a pregnancy.
Ovulation occurs at the end of the follicular phase, which starts on the first day of your menstrual period and ends with ovulation. If the egg does not fertilize, the uterine lining is shed during the part of the cycle known as menstruation.
Most people ovulate anywhere between days 10 and 17 of their cycle, which is counted from the first day of your last menstrual period. However, ovulation dates can vary from one cycle to the next, and ovulation can even occur even in the absence of a menstrual period. Tracking your cycle and using an ovulation calculator can help give a clear understanding of your ovulation schedule when trying to become pregnant.
Whathorse owners and breeding managers would give for a resource or utility thatwould allow them to precisely predict the day a mare will ovulate! While thereare numerous onlineresourcesand charts that can reliably predict parturition based on the day a mare isbred, there is not yet a handy device that can be used to predict ovulationwith the ease and low cost of a scanning thermometer or test strip. There are however,tried-and-true methods which owners, breeders and veterinarians routinelyemploy to determine when a mare will ovulate.
Mostof the available literature maintains that the mare should be bred within the12 hour period prior ovulation in order to have the best chance of getting herin foal. Unlike humans however, where ovulation might be calculated based uponthe beginning or end of a woman's last menstruation, there are no similar presentationsin the mare.
Themare may exhibit one or more within a set of behaviors signaling estrus (duringwhich ovulation occurs). These include winking of the vulva, teasing response,etc. and may include changes in temperament. However, these behaviors and theextent to which they are displayed are particular to the individual mare. Somemares display few if any obvious signs of estrus, making those behaviors onlymarginally reliable indicators of when ovulation will occur.
Withestablished baseline information on mares that have been cycling, it is easierfor the veterinarian to determine a date range for ovulation based on folliclesize (via ovarian palpation). In a breeding program, it is highly recommendedthat records are kept of these measurements, as this will help in determining atwhat follicle size the mare is likely to ovulate and the best time she shouldbe bred. Some mares may ovulate when the follicle reaches a 35 mm, while some ovulatewhen the follicle is much larger.1
A developingfollicle increases in diameter until one or two days before ovulation. When thefollicle nears maturity, it becomes softer and changes from a spherical to aconical shape. These changes take place 12 to 24 hours before ovulation, givingthe examining veterinarian information that can be used to pinpoint the optimumtime for breeding.2
Themare will normally ovulate about 24 to 48 hours before the end of estrus. Manybreeders elect to use the hormone hCG (human chorion gonadotropin) to induceovulation in order to maximize chances of the mare conceiving. Customcompounding pharmacies also offer hCG in combinationwith other drugs, such as deslorelin, which has been shown to improve the efficacyof hCG.
Each month, there are only a few days when you have the highest chances of getting pregnant. These are the days around ovulation, which is the time your ovary releases a tiny egg that is ready to be fertilised by a sperm.
Whilst an ovulation calculator estimates how likely you are to release an egg on a particular day during your menstrual cycle, a fertility calendar will tell you the days of the month that you're most likely to conceive if you have sex with your partner. Sperm can survive in your body for up to five days after intercourse, so you can conceive even after you've had sex 4 or 5 days before ovulation. Your fertiltiy window is the number of days that the egg and sperm can survive - which is normally around 6 days.
Ovulation prediction kits are readily available from pharmacies and are relatively easy to use. They work by detecting the hormone in your urine that increases when ovulation is about to take place. In addition you can use our free ovulation calculator, which is at the top of this page.
Before that data is recorded, the ovulation calculator may be off by several days. Any woman who is trying to get pregnant and notes that her cycle regularly falls outside of the 21 to 35-day range is advised to make an appointment with a fertility specialist.
Ovulation calculators and calendars are tools that attempt to predict when women might ovulate. These tools are based on the typical length of their menstrual cycle and the expected window for ovulation. These tools will guide women when they are releasing an egg each month (also known as ovulation) and when are they most fertile for the best chances of getting pregnant. Likewise, if they are taking any fertility medications, these tools can be used to suggest when they may be the most fertile for sexual intercourse. To use an ovulation calculator, women should know:
It is not advised. Some women try to use ovulation calculators and calendars as a form of natural birth control. The goal is to limit sex during predicted infertile days and abstain totally on fertile days as per the calendar. However, cycles may vary; average infertile days one month might become most fertile in the coming months. If women do not want to get pregnant, they should not totally rely on an ovulation calculator as a means of birth control. There is a significant risk that they may have an unwanted pregnancy.
Ovulation calendars may not be perfect, but they may be fairly accurate. Additionally, the results may not be right if a woman is not sure about her last menstrual period or, or for women with irregular cycles. The calculators can give an idea about likely ovulation time. Combining the results while watching for the symptoms of ovulation may improve the accuracy of the calculation. These tools are based on averages, and even if women may be charting periods accurately, the cycle length and ovulation date may vary, cycle to cycle. These tools are most beneficial to women having regular periods by calculating the average cycle length and allowing them a wider fertility window to conceive.
Methods: A total of 949 volunteers collected urine samples for one entire menstrual cycle. Luteinizing hormone was measured to assign surge day, enabling probability of ovulation to be determined across different cycle lengths. Cycle-tracking apps were downloaded. As none provided their methodology, four published calendar-based methods were also examined: standard days, rhythm, alternative rhythm and simple calendar method. The volunteer ovulation data was applied to the app/calendar methods to determine their accuracy.
Results: Mean cycle length was 28 days (range: 23-35); 34% of women believed they had a 28-day cycle, but only 15% did. No LH surge was seen for 99 women. Most likely day of ovulation for a 28-day cycle was day 16 (21%). Accuracy of ovulation prediction was no better than 21% by the apps. The standard days and rhythm methods were most likely to predict ovulation (70% and 89%, respectively) but had very low accuracy.
Conclusions: Ovulation day varies considerably for any given menstrual cycle length, thus it is not possible for calendar/app methods that use cycle-length information alone to accurately predict the day of ovulation. National Clinical Trial Code: NCT01577147. Registry website: www.clinicaltrials.gov .
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