How do i determine my due date
Calculate your due date: How to find your baby's due date
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First day of my last period
BabyCenter's Due Date Calculator
Use our pregnancy due date calculator by plugging in either the date of your last menstrual cycle or the date you know you conceived. The calculator will do the rest.
How is my due date calculated?
There are several ways your due date is determined. If you happen to know the day you conceived, you can count 38 weeks from that day to find your due date. (Human gestation takes about 38 weeks.)
But very few expectant moms know exactly when they conceived. Even if you only had sex once during your fertile period, you wouldn't conceive on that day unless you happen to be ovulating. Sperm can live for up to five days inside your fallopian tubes. So, it could be up to five days after you have sex that you release an egg (ovulate) and it gets fertilized by a waiting sperm. That's the day you conceive.
So, without knowing the day of conception, how does anyone determine a due date?
First day of your last period
The most common way to calculate your pregnancy due date is by counting 40 weeks from the first day of your last menstrual period (LMP). And that's how most healthcare providers do it.
If your menstrual cycle length is the average length (28-day cycle), your menstrual cycle probably started about two weeks before you conceived. This explains why pregnancies are said to last 40 weeks instead of 38 weeks.
This method doesn't take into account how long your menstrual cycle actually is or when you think you might have conceived. But generally speaking, women typically ovulate about two weeks after their menstrual cycle starts. And women are more likely to know when their last period started than the day they ovulated.
Conception date
If you do happen to know precisely when you conceived – say, if you were using an ovulation predictor kit or tracking your ovulation symptoms – you can calculate your pregnancy due date based on your conception date. Just choose that calculation method from the pulldown above and put in your date.
Note: Again, you don't necessarily conceive on the day you have sex.
IVF transfer date
If you conceived through IVF, you can calculate your due date using your IVF transfer date. If you had a Day 5 embryo transfer, count 261 days from your transfer date. If you had a Day 3 embryo transfer, count 263 days.
Can my due date change?
Your healthcare provider might revise your due date if your baby is measured during a first trimester ultrasound scan and found to be much bigger or smaller than expected for gestational age. This is more likely to happen if you have an irregular menstrual cycle length that makes it hard to pinpoint the date of conception.
Your healthcare provider will measure your baby during that ultrasound exam to figure out how far along your baby is and then provide you with a new due date.
What if I already know my due date?
If you already know your due date, you can use this calculator to see your pregnancy timeline. It will tell you when you'll hit various milestones, and when you may be due for prenatal tests and prenatal visits. You'll also find what your baby's sign and birthstone will probably be and which famous people were born on your due date.
How likely am I to give birth on my due date?
Of course, a due date calculation is always approximate, whether it's from our tool or from your doctor or midwife. Only 1 in 20 women delivers on their due date. You're just as likely to go into labor any day during the two weeks before or after.
Want more information about how the weeks, months, and trimesters of pregnancy are counted? See our pregnancy timing chart.
How soon can I take a pregnancy test?
With all this talk about pregnancy due dates, you may be wondering when you can take a pregnancy test. To ensure you get the most accurate reading, it's best to wait a few days after your missed period to take a pregnancy test.
At-home urine tests measure the amount of hCG (human Chorionic Gonadotropin) present in your body. If you take a pregnancy test before you miss your period, you may not get an accurate result, despite what some tests advertise.
If you're getting a blood test in your provider's office, you may get results sooner. These tests also measure the amount of hCG in your bloodstream, but they're more sensitive than at-home urine tests. Blood tests may be able to detect pregnancy six to eight days after ovulation.
Read more
- Your pregnancy, week by week
- Your first trimester pregnancy checklist
- Pregnancy Weight Gain Calculator
- Ovulation Calculator
- See all tools
Chinese gender predictor chart and calendar tool
Wondering whether you're having a boy or girl? Our Chinese Gender Predictor calculator forecasts your baby's sex based on an ancient Chinese gender chart and the Chinese lunar calendar.
There's no scientific evidence that the Chinese Gender Predictor works. But since there are only two choices – boy or girl – it has at least a 50-50 chance of making an accurate prediction!
What is the Chinese gender predictor chart?
Legend has it the chart is more than 700 years old and was discovered in a royal tomb near Beijing. The technique involves converting the mother's age and the month of conception to dates on the Chinese lunar calendar, then cross-checking that data on a chart that predicts the baby's sex.
How accurate is the Chinese gender predictor chart?
Researchers at the University of Michigan School of Public Health did a study to test the Chinese lunar calendar method of predicting a baby's sex. They reviewed the records of 2.8 million Swedish births. Then they used a website-customized algorithm to estimate each mother's lunar age and month of conception. When they checked the predictions of the Chinese baby calendar method against the sex of the children who were born, they concluded that the Chinese birth chart was correct about 50 percent of the time -- no more accurate than flipping a coin.
How can I really tell what my baby’s sex will be?
There are several ways.
You can find out your baby's sex starting at 10 weeks of pregnancy if you have noninvasive prenatal testing (NIPT), a blood test that can detect Down syndrome and a few other chromosomal conditions. (It takes a week or two to get the results.)
Many pregnant women find out their baby's sex (if they choose to know) during their midpregnancy ultrasound, which is usually done between 18 and 22 weeks. However, if the technician can't get a clear view of the baby's genitals, it may not be possible to tell for sure.
Other women find out their baby's sex from a genetic test like chorionic villus sampling (CVS) or amniocentesis. These tests are usually done to determine whether a baby has a genetic disorder or a chromosomal abnormality, like Down syndrome. CVS is usually done between 10 and 13 weeks, and amniocentesis between 16 and 20 weeks. You have to wait for 2 weeks for the results from both tests.
If you have IVF, you can find out the sex before you even transfer the embryos. But if you have embryos of both sexes placed in your uterus, you won't know which one(s) implant.
At-home gender kits (available mostly online) test blood or urine to predict your baby's sex, but there's no scientific evidence that these tests really work.
What's the difference between gender and sex?
We're using the word gender here because people often use this word when talking about their child's sex. However, the two are not the same. A child is generally assigned a sex at birth based on biological characteristics, such as their genitals. But their sex designation may not match the gender identity (based on feelings and behaviors) that they assume later.
Learn more:
Gender prediction: Am I having a girl or a boy?
When and how can I find out my baby's sex?
15 fun baby gender predictor tests to try
Video: Should we find out our baby's sex?
All tools
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How to correctly calculate the gestational age and determine the date of delivery
It often comes as a surprise to first-time pregnant women that in obstetrics the gestational age is determined not in months, but in weeks. But the surprises do not end there - the fact is that the obstetric period is calculated not from conception, but from the first day of the last menstruation.
In fact, pregnancy occurs two weeks after the start of the obstetric period, at the time of ovulation, when the sperm meets the egg. Thus, the age of the embryo, or gestational age, differs from the obstetric one by 2 weeks down.
How long does pregnancy last?
The obstetric term of a term pregnancy is 40 weeks, or 280 days. It is on the basis of the obstetric gestational age that the doctor will prescribe tests and examinations for you, determine the date of maternity leave and calculate the EDD (estimated date of birth).
Doctors use the Negele formula to calculate the EDD. According to this formula, if we add nine months and seven days to the first day of the last menstruation, we get the estimated date of delivery.
Unfortunately, determining the gestational age from the first day of the last menstrual period is not a very accurate method. It is well suited for women with a stable 28-day cycle, but if your cycle is slightly longer or shorter, then the date of ovulation shifts, respectively, and the actual obstetric gestational age will differ from the established one.
The most accurate way to calculate the EDD is to add 266 days to the date of the last ovulation (if you know it).
How to confirm pregnancy, determine the duration of pregnancy and the date of delivery
By itself, a delay in the start of a new menstrual cycle does not necessarily indicate pregnancy - failures can be explained by diseases, excessive physical exertion or stress. Pregnancy must be confirmed with an hCG test or examination on a gynecological chair. 1) Blood test for hCG cycle or the woman will feel the first symptoms. Also, an analysis of the level of hCG in the blood allows you to determine the gestational age with an accuracy of about two weeks.
2) Home pregnancy test
Home pregnancy tests also work by measuring hCG levels, but they are less sensitive than blood tests. The most modern of them can not only confirm the presence of pregnancy a few days before the delay, but also indicate (not too accurately) an approximate date.
Tests of the old generation will show a more or less accurate result only after a delay, that is, after 2-4 weeks from conception.
3) Gynecological examination
A qualified gynecologist-obstetrician can diagnose pregnancy during an examination starting 3-4 weeks after conception, focusing on changes in the shape and size of the uterus, as well as other signs.
4) Ultrasound
Ultrasound is the most accurate way to diagnose pregnancy. With the help of ultrasound with a transvaginal sensor, it is possible to determine the presence of a fetal egg in the uterus already 1-2 weeks after conception (3-4 obstetric weeks), but fetal heartbeats can only be detected for a period of 5-6 obstetric weeks. It is possible to determine the gestational age with high accuracy (up to 2-3 days!) With the help of ultrasound only from 6-7 weeks.
If the delay, as well as the result of an hCG test or blood test, indicate that you will soon become a mother, do not rush to get an ultrasound right away. Wait another 2-3 weeks, then by ultrasound you will not only be accurately determined by the period, but will also be allowed to listen to the baby's heartbeat.
If you did not do an early ultrasound to confirm pregnancy, then for the first time you will encounter this study at the 10-14th week. At the same time, the exact gestational age and PDR will be established or corrected for you. During pregnancy, you will need to undergo such an examination at least twice more. This will happen at 20-24 and 30-34 weeks. However, it is worth saying that ultrasound in the 2nd and 3rd trimesters may have an error in determining the gestational age. The PDR established according to them may differ from the real one by 2-3 weeks. That is why it is so important not to miss the first screening and do an ultrasound on time.
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How to calculate due date. Calculate gestational age by week
Our online pregnancy calculator will help you calculate your gestational age by week and find out when your baby is due
Start date of last menstrual period
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Calculate the due date
It is impossible to calculate the due date with absolute accuracy. The estimated day of delivery is calculated as follows: the first day of the last menstruation + 280 days . This is an average date, usually delivery occurs in the next plus or minus 10 days . Learn more about the calculation of the PDR.
I'm pregnant
Pregnancy Calendar Ovulation calculator pregnancy weight gain calculatorHow to calculate due date
What is EDD?
EDD is an abbreviation commonly used by physicians for the phrase "estimated due date".
How is the expected date of delivery (ED) determined?
How to calculate the due date correctly? Pregnancy from conception to the birth of a child lasts about 266 days, or 38 weeks. Since the date of conception, as a rule, is not exactly known, in modern obstetrics it is customary to calculate the gestational age from the first day of the last menstruation, i.e. you need to calculate the date of birth by menstruation. With this calculation, it is approximately 280 days, or 40 weeks, since ovulation and, accordingly, fertilization usually occur two weeks after the start of the cycle. Ultrasound equipment is also set up for the same calculation of the gestational age, therefore, if menstruation is delayed by 4 weeks, the doctor will most likely report 8 weeks of pregnancy (whereas only about 6 weeks have passed from the moment of conception).
Accuracy of due date calculation
How to calculate exact gestational age? You can calculate the approximate date of birth of a child if you know the date of the last menstrual period. The estimated due date (EDD) will be 280 days (40 weeks) after the first day of your last period. However, only 5% of children with normal pregnancies are born on the “calculated” day, another 85% are born within a period of plus or minus a week from this date, and another 10% are “late” or “hurry” for another week. It is believed that a healthy pregnancy can last from 38 to 42 weeks.
Duration of pregnancy
How to correctly calculate the duration of pregnancy? The duration of pregnancy depends on many factors, including the individual pace of development of the child, as well as the duration of the woman's menstrual cycle. So, for example, if the cycle duration is less than 24 days, then childbirth can occur 10-15 days earlier than when calculated according to the formula "1st day of the last menstruation + 280 days", while the child will be fully mature and healthy. And if the menstrual cycle lasts more than 32 days, then the pregnancy can drag on for 10-15 days, and this will not be considered overdose.