Term and Ovulation
Calculate your ovulation and future term
Our Pregnancy Calculator – Ovulation and Due Date will inform you of important dates related to your pregnancy:
- Calculates date of ovulation – the most fertile period
- Calculates date of term
- Calculates which gestational week you are in
- Calculates date of conception
- Calculates the first day since your last brick
- Calculates time of probable conception
- Calculates the weeks until the end of pregnancy
- Calculates important dates related to the fetus and the visit to the geneticist
Nutritional Supplements Suitable for the First Trimester of Pregnancy
Please note that the pregnancy calculator may give up to a few days deviation. Your gynaecologist will be able to advise you on more specific dates related to your pregnancy.
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How do I determine my due date?
Your due date is calculated from the first day of your last regular period, i.e. the duration of pregnancy is 280 days – 10 months of 28 days (lunar months) or 40 weeks of 7 days (gestational weeks) without a period. According to the formula of Negele, the date of the term for childbirth is calculated by subtracting three months back from the first day of the last regular menstruation and adding seven days to this day.
For example, if your last menstruation started on April 10 (10.04): April is the fourth month minus three months, this makes January 10 (10.01); to this date we add another 7 days (10.01 + 7 days = 17.01); therefore the probable date of birth in this case is January 17.
Naturally, you also have to take into account that the year has 12 months. If your last period started on January 15, for example, subtracting three months makes October 15 and adding 7 days, so your due date would be October 22.
According to statistics, only about 5% of children are born exactly on the date set as the term of birth, calculated by the method of the first day of the last menstruation. In the last months of pregnancy, your obstetrician-gynaecologist could determine the happy day much more accurately – this is done by measuring the baby, judging its condition and your organism.
The term of childbirth can also be determined by the date of fertilization (conception) – from the 3rd week of amenorrhea (the absence of menstruation). In this case, the duration of pregnancy is 266 days (approximately 9 calendar months), calculated from the time of fertilisation (about two weeks before the date of your next expected menstruation). This method of calculation is less accurate as not all women ovulate exactly on day 14 of their cycle. Therefore, the Negele method has been adopted as the international norm for calculating term birth and for tracking pregnancy by weeks. It is safer because almost every woman knows the exact date of her last period.
What methods of calculating ovulation are there?
1. Calculation of ovulation by the calendar method
If you have a strictly regular cycle this method of calculating ovulation is very accurate. This method is easy to use and is a useful step for gathering data to track your cycle milestones. To implement the method, you only need an ordinary calendar, on which you need to put a circle on the date of the first day of your cycle, which is the day of the start of the actual menstruation. Keep an eye on the cycle length, which is usually 28 days. Note the duration of menstruation, with the last day being the first of the start of the new cycle. Do such follow-up within about 8 to 12 cycles. Make a diagram of the cycle length. Once you have recorded at least 8 cycles, you can convert the data into a chart. In this way you will detect how many days your cycle lasts on average and you will know when is the middle of it, respectively exactly in the middle of your menstrual cycle is your ovulation. We note again, however, that the method is not absolutely reliable. Today, a number of smartphone apps have already been created to quickly and easily use the calendar method to accurately calculate your ovulation and reach your desired ovulation.
2. Calculation of ovulation by the cervical mucus method
Understanding the role of cervical mucus is a good indicator of when your ovulation period is. Cervical mucus is the protective substance that is secreted from the cervix, and it changes at different stages of your cycle. Your body produces more mucus right around the time of ovulation to help facilitate the movement of sperm and, consequently, the fertilization of the egg. Once you learn to observe your cervical mucus and the changes in it – it is possible to use the method to predict when your ovulation day is. Notice the changes in color and odor, as well as in the texture of your mucus. Note whether the mucus is cloudy or clear. Record as thoroughly as possible your observations of your mucus and especially in the first few months when you are still exploring how to use this method to get to a positive pregnancy test more quickly. Breastfeeding, infections, certain medications, and other circumstances can affect cervical mucus, so be sure to pay attention to these factors as well. The day of ovulation is usually the day when cervical mucus is most wet i.e. greater in quantity and slippery.
3. Calculate ovulation by tracking basal temperature
A woman’s most fertile time is just before ovulation. This method is one of the most used, it is done in the morning before you even get out of bed, while the body is still at rest. Buy a thermometer to measure your basal temperature. Your body temperature rises slightly when a woman is ovulating. The most accurate readings are taken in the vagina or rectum, but there are also basal thermometers designed to take readings in the mouth. It is necessary to measure your temperature daily. It is important to take temperature data at the same time each day as it changes throughout the day. Ideally, take your temperature before you get out of bed in the morning, after at least five hours of sleep. Record your temperature within 1/10 of a degree. Use a dot or other symbol on your chart to mark days when other factors may change the readings, including illness, restless sleep, and taking medications such as aspirin, etc. A woman’s average body temperature is 35.6 – 36.7ºC before ovulation, and 36.1 – 37.2ºC after ovulation. If you get results significantly outside this range when calculating ovulation, consult the instructions on the thermometer to make sure you have used it correctly. If you decide to use this method to measure ovulation, contact a doctor who will explain in detail how to proceed in order to get pregnant faster.
4. Calculating ovulation by ovulation tests
Straight ovulation test kits are available in pharmacies. These kits detect the increase in the amount of luteinizing hormone (LH) in the urine, which increases one to two days before ovulation. Like pregnancy tests, they show two dashes if they report an increase in the hormone levels in your urine. This is the easiest method and is relatively reliable, but it is more expensive than the others. It is a good idea to do such tests within a few months until you specify your ovulation time. Drink a moderate amount of water in the hours before the test. Very concentrated or very dilute urine can taint the results of this test. For best results, avoid caffeine and alcohol on test day.
5. Estimation of ovulation by methods of detecting fertility problems through medical consultation
Visit a doctor for the most accurate ovulation calculation. Tests that a specialist can prescribe are more accurate than home methods. These may include a blood test to measure progesterone and other hormone levels, or tests to detect abnormalities in thyroid function or prolactin levels if your doctor thinks they are the likely cause of your fertility problems. Ultrasound examination can be used to detect structural abnormalities in the reproductive tract, which can also affect ovulation. It’s a good idea to get your sexual partner checked out too. Men can also be tested for infertility. This usually begins with semen testing and may continue with an ultrasound test to detect possible problems in the male reproductive system. If the doctor suspects that you are infertile due to anovulation (lack of ovulation), he may recommend a number of medications depending on your exact condition. Your doctor should consider the possibilities of blocked fallopian tubes, a problem with the quality and quantity of live sperm, problems with the uterus or egg implantation, and those associated with a decline in egg quality due to the patient’s age.