Due Date Calculator For Irregular Periods

What Is Gestational Age Can It Be Different Than What The Calculator Shows

IRREGULAR PERIODS? How To Calculate Safe Period & Ovulation Date For Irregular Periods

Gestational age is the term used to describe how far along the pregnancy is and how long baby has been gestating .

If you get an ultrasound you may notice a GA on the image with a number of weeks and days. This figure is based on how the baby is measuring, not on your LMP, which the due date calculator uses.

Its normal for these dates to not match up perfectly. If there are significant differences in the dates, your doctor may want to dig deeper to determine conception date. As a result, your midwife or doctor may change your due date based on the ultrasound gestational age.

Early ultrasounds are very accurate when dating a pregnancy and can be helpful if you dont know your LMP or your periods are irregular.

Note that you dont have to have an early ultrasound, especially if you are fairly certain of your cycle length and conception window. This study shows that early dating ultrasounds dont change the incidence of induction.

Can I Plan My Due Date

Whether you’re trying to avoid being very pregnant in the middle of summer or are a teacher who wants to maximize time off with your little one, you can try to time when you conceive in order to “plan” your due date. But even if you’re one of the lucky ones who’s able to get pregnant when she really wants to, just remember that you probably won’t be able to map out exactly when you’ll give birth to the day .

Still, you can try our Ovulation Calculator, which uses the date of your last menstrual period and your typical cycle length to discover the days you’re most likely to be fertile and increase your chances of conceiving.

What Does It Mean If My Doctor Changes My Due Date

Your doctor may change your due date if your fetus is significantly smaller or larger than the average fetus at your particular stage of pregnancy.

Generally, your doctor orders an ultrasound to determine the gestational age of your baby when theres a history of irregular periods, when the date of your LMP is uncertain, or when conception occurred despite oral contraceptive use.

An ultrasound allows your doctor to measure the crown-rump length the length of the fetus from one end to the other.

During the first trimester, this measurement provides the most accurate estimation for the age of the baby. Your doctor may change your due date based on the ultrasound measurement.

This is most likely to occur in the first trimester, especially if the date estimated by the ultrasound differs by more than one week from the date estimated by your doctor based on your LMP.

In the second trimester, an ultrasound is less accurate and your doctor probably wont adjust your date unless the estimates vary by more than two weeks.

The third trimester is the least accurate time to date a pregnancy. Estimates based on an ultrasound can be off by as much as three weeks, so doctors rarely adjust dates during the third trimester.

However, its not uncommon for a doctor to perform an ultrasound in the third trimester if theyre thinking about changing your date.

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How Does My Provider Decide My Due Date

The first due date that your provider tells you is usually based on your last menstrual period and the size of your uterus at your first visit. The time of conception is usually 2 weeks after your last normal period. Most babies are born about 40 weeks after your last menstrual period. This means time from conception until your due date is about 38 weeks. Most babies grow at the same rate early in pregnancy so the size of your uterus at your first visit can help your provider estimate your due date.

Reverse Due Date Calculator

Pregnancy estimating conception date, how to conceive a ...

A reverse due date calculator uses a method thats the exact opposite of a due date calculator.

It works when you know your pregnancy due date and want to figure out when conception happened.

This might be because you want to know when you conceived but cant remember your LMP.

Or perhaps you want to plan conception, and want to avoid having a baby at a certain time or year or month.

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How Far Along Am I

enterdue datelast period

The How Far Along Am I Calculator uses your due date or last menstrual period to calculate how many weeks, months, and days you are pregnant.

different starting dates to count pregnancy

  • Conception or ovulation
  • Measurements from an ultrasound
  • IVF Transfer date

Pregnancy is most commonly measured gestationally from a woman’s last menstrual period to birth. This period is known as gestational aging.

If you require more options to calcuate yourdue date or how far along you are, try ourdue date calulator.

How To Calculate Due Date With Irregular Periods

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Using The Pregnancy Calculator By Due Date

pregnancy calculator by due date is essential for any woman trying to conceive. Most women try everything, including reading the womens health magazine, searching for an effective way to help them track their pregnancy successfully.

Women have various reasons for doing so. Some try to avoid getting pregnant during summer. Or, if youre in a full-time job, you may want to maximize your time with your kid. Whatever the reason, timing your conception will enable you to plan your due date effectively.

Its not easy, mainly if youre relying on manual methods. But with thepregnancy calculator, you will have an idea of when your baby will be born. While its not an exact science, a pregnancy calculator will provide an estimate of when youre likely to give birth.

You can use the pregnancy calculator to estimate your due date in various ways:

Disclaimer About The Calculator


Our calculator strives for the highest accuracy, but your pregnancy progress may differ from the calculator’s results for several reasons including possible miscalculation errors in input data individual variations in the timing of ovulation, and/or conception.

The information provided regarding pregnancy progress and fetal development is a guide through the weeks. It is not specific information for a specific individual but serves as a general guide only. As each pregnancy differs, any dates, weights, and lengths should be considered general information for interest only.

Our week-by-week guides use both standard and metric units of measure including pounds and kilograms.

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What Is The Date Of Conception

Conception occurs after ovulation, when the sperm meets the egg. For instance, if you had intercourse on the 5th of the month, and you did not ovulate until the 8th of the month, the conception will occur on or just after the 8th. If you have a 28 day-cycle, conception is known to occur between 11 and 21 days after the first day of your LMP. As most of us do not know the date of conception, it is taken as an estimate based on the LMP method.

How Do You Estimate Baby Due Date Using Conception Date Calculator

If you are keeping a track on your ovulation and know the fertilization date, you can estimate the due date based on the date of conception. The estimated due date, in this case, will be 38 weeks from the date of conception. Only a few women can accurately track the ovulation days and can guess when they have conceived. But, the calculations can go wrong as you may not conceive on the same day of the intercourse. The sperm can live up to five days, and the ovum for up to 24 hours after being released. In short, there is only a six-day fertile window where you can get pregnant.

In cases of in-vitro fertilization, the date of conception would be precise.

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Division Of Pregnancy Trimesters:

Disclaimer: While our tool gives you a tentative due date and other details, it cannot replace a medical consultation. Visit a physician for confirming your EDD based on your complete medical history.

Our calculations are only an indication. MomJunction is not liable for any related issues, consequences or damages.

The First Day Of Your Previous Period

Calculate Pregnancy Due Date If Period Irregular ...

It takes about 40 weeks for pregnant women to give birth. So by counting 40 weeks or 280 days, from the first day of your last period will provide you with a due date estimate.

Also, by subtracting three months from the first day of your last period and adding seven days, youll find your due date. Since its tricky to count manually, pregnancy due date calculator will come in handy. Note that you will likely give birth between 1-2 weeks before or after the estimated due date.

Conception date Calculating the due pregnancy date on the first day of your last period doesnt work for women with irregular cycles. So a pregnancy due to date calculator can also help you estimate your due date based on the conception date. Adding 266 days to your conception date will give you an estimate of your due date.

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Could My Due Date Change

The actual date the sperm and egg join is almost never known for sure. Your provider will likely recommend that you have an ultrasound once or twice in the first half of your pregnancy to make sure your due date is correct. The ultrasound can measure the size of your baby and use that information to figure out your due date. Your provider will likely recommend you have an ultrasound during your first trimester if you are not sure of the day your last period started, you had spotting or an abnormal period, you have irregular periods, or your provider’s findings on your exam do not match the due date based on your last menstrual period. The due date based on a first trimester ultrasound is usually the most accurate . The ultrasound due date will be used if there is more than a week or so difference between the due date based on the ultrasound and the due date based on your period.

  • What information about my due date is the best?
  • What information is causing my due date to change?
  • How will this change affect my care, now or later?

Tracking Your Menstrual Cycle

It is important to keep track of your cycle because each time you visit a physician, she will ask you the first day of your last period. Your physician asks this to not only make sure that you are not pregnant, but also to make sure that you are not experiencing problems with your health. If you are younger than 40, missing or irregular periods might indicate that you have a health problem, such as poor nutrition.

If you have regular periods and suddenly your period is a week late, for example, you should take a pregnancy test. In addition, if you decide to try to become pregnant, knowing your cycle can help you determine the best days to have intercourse to conceive. Alternatively, knowing your cycle can also help you avoid pregnancy because you can avoid having intercourse of the days where you are probably the most fertile.

To calculate the length of your cycle, begin with the first day you begin spotting or bleeding. This counts as day 1. Then, track the days until the next one begins. The time from the first day you begin spotting or bleeding to the last day before you begin spotting or bleeding again is your cycle.

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How Does This Due Date Calculator Work

Because you may not know exactly when you ovulated or conceived, a due date calculator will typically calculate your estimated due date based on your last menstrual period .

Our online due date calculator uses a simple method to calculate your due date.

  • Your due date is estimated to be 40 weeks after the first day of your LMP
  • Your cycle is assumed to be 28 days long, with ovulation occurring at day 14
  • Therefore the calculator adds 280 days to your LMP

This method of due date calculation is known as Naegeles rule .

Estimation Of Due Date

Know How to Calculate LMP for Due Date | Pregnancy Calculator | Pregnancy week by week

The due date, also known as the estimated date of confinement, is an estimation of when a pregnant woman will deliver her baby. While the due date is often estimated as a single date, it can be helpful to consider a range of due dates, since only 4% of births occur on the estimated due date.1

Due dates can be estimated using a number of different methods, including the last menstrual period, ultrasound, conception date, and IVF transfer date.

Last menstrual period

The default for this calculator bases the calculation on a woman’s last menstrual period , under the assumption that childbirth on average occurs at a gestational age of 280 days, or 40 weeks. Although there is some debate regarding when pregnancy technically begins, whether at fertilization of the egg , or when the egg adheres to the uterus , gestational age does not vary based on different definitions of pregnancy since it is based on LMP. In terms of gestational age, pregnancies typically last between 37 and 42 weeks, with 40 weeks often being used as an estimate in calculations. Thus, the due date is usually estimated by calculating the date that is 40 weeks from the start of a woman’s LMP.


Conception date

Using conception date to estimate due date is similar to using the last menstrual period, except for a difference of about two weeks in the point of measurement, based on the timing between the last menstrual period and the date of conception.

In vitro fertilization

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Why Is The Date Of Conception Important

Most due dates are calculated off of a womans last menstrual period . Thats how our due date calculator works. The problem is that this method of establishing an estimated due date isnt always accurate, especially for women who dont have a standard 28-day cycle. Still, its become the standard, since most women are more likely to know the exact date of their LMP than the exact date they ovulated.

The whole concept is a bit confusing though. According to this pregnancy dating method, your firstand sometimes even secondweek of pregnancy occurs before you even did the deed! Huh?!

Therefore, pinpointing conceptionwhen sperm and egg actually meet to create new lifeis a much more accurate representation of when your pregnancy began. And it can help you answer the question How many weeks pregnant am I?

If youre currently pregnant, having a clear idea of when your pregnancy actually began is important at the end of your pregnancy when the conversation may turn to induction. There are risks for both mama and baby if induction occurs before the body is ready to go into labor, so if your healthcare provider thinks youre further along than you really are, you could be encouraged to try induction sooner than necessary.

And thats where the reverse due date calculator comes in.

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