If my last menstrual was

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.

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How are Due Dates Calculated

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Dani Kurtz Dec 3, 2015

If you were having regular periods before pregnancy, your doctor will calculate your due date based off of your last menstrual period. This goes back to the fact that in order to get pregnant, your body ovulated—or released an egg—roughly in the middle of your cycle and it was fertilized by sperm. That was the moment of conception.

By the time most women miss a period and find out they’re pregnant, the baby has been growing for 2 weeks, but the mother is actually 4 weeks along because the gestational period starts with the first day of your last period.

To clarify, the gestational period of 40 weeks actually starts with the first day of your last period, which adds two weeks of time to the gestational period when your baby didn’t even exist yet…clear as mud, right?

Is an ultrasound a more accurate way of finding out my due date?

If you are having irregular cycles before getting pregnant, an ultrasound is usually done to find out how far along you are. An ultrasound is actually the most accurate way to date a pregnancy because all fetuses grow at a consistent rate during the first trimester and early second.

In other words, if your baby measures 9 weeks 2 days when you have your ultrasound, that’s how far along you are, no matter when your last period was.

Some women with regular cycles are confused about why their ultrasound due date doesn’t match up with their last menstrual period due date. Ovulation isn’t a perfect science and can happen earlier or later than the norm, which might shift your due date slightly.

That’s okay…a few days or even a week of discrepancy won’t change your dates. Your doctor will go with the due date obtained from your ultrasound.

What happens if my baby is measuring big or small later on? Does my due date need to change or will I deliver early?

You’ll notice at every prenatal appointment after 20 weeks, your doctor will measure your belly. That measurement should match your gestational age in centimeters. If you are measuring smaller or larger than what you should be, then the doctor might order an ultrasound. This will tell them if the discrepancy is due to the actual size of the baby, the amount of fluid surrounding the baby, or maybe just the way you’re carrying the baby.

If the baby is actually smaller or larger than what they should be, underlying issues need to be considered that might be causing the discrepancy in growth. For example, mothers with uncontrolled diabetes (Type 1, Type 2, or Gestational) cook very large babies. When a baby is small, it might be due to a placenta that’s not working like it should.

These discrepancies might affect delivery, but they might not. For example, if your baby is consistently measuring small and falling below where they should be, your doctor might decide you need to be delivered because your baby would be better out than in.

If your baby is extra big and you’re measuring 40 weeks at 37 weeks, your body might think it’s done and go into labor early….or you might go to your due date and things will go as planned. If you have questions about your due date, talk with your doctor who can give you the best information.

Intermountain Moms

Last Updated: 10/27/2017

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Pregnancy in questions and answers - Useful articles

What to expect? How to eat? How to deal with difficulties? How to do everything right? These and many questions will be answered by Irina Alexandrovna Soleeva, an obstetrician-gynecologist at the Sadko clinic.

- How is due date calculated?

From the first day of the last menstruation. To determine the due date, 280 days are added to the first day of the last menstruation, i.e. 10 obstetrics, or 9calendar months.

Usually, the calculation of the due date is simpler: from the date of the first day of the last menstruation, 3 calendar months are counted back and 7 days are added. So, if the last menstruation began on October 2, then, counting back 3 months (September 2, August 2 and July 2) and adding 7 days, determine the expected date of birth - July 9; if the last menstruation began on May 20, then the expected due date is February 27, etc.

Expected due date can be calculated by ovulation: from the first day of the expected but not arrived menstruation, count back 14-16 days and add 273-274 days to the found date.

- And if you know the exact date of conception, how many days to add?

A large-scale study was conducted with a large number of pregnant women, according to various indicators, the gestational age and, accordingly, the date of birth were determined. It turned out that the woman most often remembers the date of the last menstruation. And from this fixed date, as the study showed, childbirth occurs at the 40th week ± a couple of weeks. Obstetrician-gynecologists are guided precisely by this system of calculations.

- Should I change my diet, if so, how?

4 meals a day are recommended in the first half of pregnancy, 5-6 meals a day in the second. It is better to eat often, but little by little. For healthy women, there are no forbidden foods (except alcoholic beverages), only more or less preferred ones.

So, the body absorbs easily digestible milk fats and vegetable oils better. The latter are not only a source of essential linoleic acid, but also vitamin E, which has a positive effect on the course of pregnancy.

To eliminate constipation, it is worth enriching the diet with sources of dietary fiber (fiber, pectins) - vegetables and fruits, buckwheat and oatmeal.

In the second half of pregnancy, sugar, confectionery and flour products, rice should be eaten in very small quantities. Do not get carried away with fried, spicy, salty foods, because. during this period, the liver and kidneys of a pregnant woman function with tension. It is better to prefer boiled and steamed dishes.

The main thing is to include a variety of foods in your diet: vegetables, fruits, juices - and you will provide yourself and your unborn child with everything necessary for normal development.

- I really want olives, but they are canned. Can?

It depends on the gestational age. After 20 weeks, I would not recommend eating too salty foods, including olives. And in general, any canned food is not the most suitable food for a pregnant woman. Although olives, in themselves, the product is very useful. Therefore, within reasonable limits, say, a jar can be eaten in two days.

- And the grapes?

Grapes are very well digestible. It's fructose. It is immediately absorbed and quickly raises blood sugar. But if you are overweight, it is either not recommended at all, or it is allowed in small quantities. It is allowed to eat a small brush, or you can treat yourself to something else.

For some reason, it is customary for us to believe that if you are pregnant, you have to eat for three or whatever you want. As a result, pregnant women buy grapes in boxes and eat them in kilograms. Such a diet does not lead to anything good: sugar appears in the urine, blood sugar rises, babies are born large. Moreover, a large load falls not only on the mother's pancreas, but also on the child's pancreas - the baby from birth will be predisposed to being overweight.

- Is it possible to reduce excess weight during pregnancy and cleanse your body with the help of special teas?

All cleansing teas are contraindicated during pregnancy. We have drugs that improve the functions of the liver and kidneys, which have a diuretic effect. We assign everything individually. There are no special cleansing procedures during pregnancy. However, we have fasting days - here is the best cleansing procedure for you.

- Which vitamins are best for pregnancy?

Now there is a huge selection of various vitamin complexes for pregnant women. Of course, they are all close to each other in composition. One or two components or the dosage of some vitamin differ. In order not to harm yourself and the baby, to achieve the maximum effect, each patient needs to select vitamins, based on the advice of her doctor, who controls the course of pregnancy.

- How long should I take them?

Do not take multivitamin preparations continuously. The necessary course can be selected only by a doctor, taking into account the state of your body. We have different periods when it is better to stop taking vitamins altogether. In certain weather seasons, when there is enough sun, fresh vegetables and fruits, there is no need to take vitamin complexes.

- Can I continue playing sports?

Not only possible, but necessary. From the first months of pregnancy. They will help to maintain good physical shape, and this will definitely help during childbirth, relieve excessive tension and improve mood. The main thing that you should not forget is that the training program should be specially adapted for pregnant women and should be carried out under the supervision of a doctor or an experienced instructor.

- Do I really have to push in prenatal classes? Will not diligence create the danger of premature birth?

No, there is no danger in this exercise. If there is anything to beware of, it is cycling, horseback riding, roller skating - all sports with an increased risk of injury.

- Can I take a contrast shower?

If a woman used this procedure before pregnancy. But during pregnancy, the water should not be too hot. By the way, hot baths and a bath should also be excluded.

- Can I continue to have sex while pregnant?

Each couple decides for themselves. If it gives pleasure to both, if the woman is comfortable, then you can keep your sex life almost until childbirth. Of course, too active sex will have to be excluded, and completely stopped 2-3 weeks before the birth: too vigorous sexual intercourse: it can provoke premature birth.

If earlier it was very strict: from 30-32 weeks, sexual life stops, now sex life is excluded by the doctor only if there are any deviations. After a while, he may allow you to resume intimacy. There are cases when sexual life is excluded for all 40 weeks.

- Do I need to use protection during pregnancy in order not to get pregnant again?

Very funny question. If one pregnancy has already occurred, re-conception during this period can no longer occur. The need for protection is therefore eliminated.

- Can I sleep on my stomach?

On short terms it is possible. The uterus comes out of the pelvic cavity after 12-13 weeks. Before that, it is protected by the pelvic bones, which means that we will not cause any harm to the fetus.

- So, the work of the expectant mother. Is it worth revising your working day, taking into account the new state?

Working during pregnancy is perfectly acceptable if there are no abnormalities. It is important to remember that pregnant women should not lift weights, work in heat and high humidity. Contact with harmful substances and prolonged standing should be avoided.

- Can motorists continue to drive?

You can drive a car if there are no contraindications from the doctor who monitors you during pregnancy. And it is not desirable in the later stages after 30 weeks, because there is a very strong load on the muscles of the pelvic floor, legs and arms work, concentration of attention is required - this is an additional stressful situation for your body. And of course, do not neglect the seat belt. He will not pull your stomach, but will pass under it and under your arm obliquely.

- How to deal with the symptoms of varicose veins?

It depends on the degree of varicose disease, its severity. Despite the rich selection of various drugs for internal and local action - tablets, drops, ointments - the most effective method of struggle is, nevertheless, wearing compression underwear. By the way, those who spend most of their working time sitting at a table, or vice versa, standing on their feet, should also think about the prevention of varicose veins.

It is better to stop your choice on tights: an elastic band or a stocking squeezes the leg too much, and when bandaging the legs, it is difficult to determine the necessary compression.

Tights should be selected by a doctor. A phlebologist works in our clinic. He will be able to choose the desired degree of compression.

Do not be afraid that underwear will be too tight on both legs and stomach: there are special tights for pregnant women. A special insert on the stomach fits him, supporting him, without squeezing at all.

- How to be smokers: won't quitting a bad habit cause stress for the body if the smoking experience before pregnancy was quite long?

Smoking during pregnancy is very bad. This applies equally to active and passive smokers. The fetus develops chronic hypoxia - a constant lack of oxygen. And it primarily affects the development of brain structures. The result is deviations from the norm in mental development. Even if the violations are minor at first, in infancy, most likely, they will manifest themselves in kindergarten or school, when the maximum load falls on the child's intellect. It will be difficult for the baby to learn, to perceive some information.

Moreover, there is a growing threat of premature births, miscarriages at different stages of pregnancy. Babies are often born small.

Stories that giving up habitual smoking will become a strong stress for the body are far from the truth. Our expectant patients break this bad habit without much difficulty. Even if you regularly inhaled tobacco smoke both before and after conception, you should not think that it is still too late to quit. The harm you will do to your baby if you continue to smoke is incomparable to the reluctance to part with a cigarette.

- Where and how to find a qualified doctor who can be trusted to take care of yourself and your unborn child?

The women's health center of the "SADKO" clinic gathered the best specialists of the city: obstetricians-gynecologists, mammologists, ultrasound doctors, therapists, psychologists, exercise therapy doctors. Modern equipment of gynecology allows you to accurately and quickly carry out all the necessary diagnostics, and, if necessary, treatment. The advantages of such an integrated approach are obvious: you don’t have to go far, but the main thing is that you are served by one team, one hand. We will be happy to help both expectant mothers and those who really want to become them.

How do I know exactly what day I got pregnant?

August 21, 2020

Many women are very concerned about this issue, because the more accurately you can determine the date of conception, the easier it will be to predict the date of birth of the baby. But is it realistic to determine the exact date of conception and how to do it? Let's find out.

First of all, you should know that the date of conception always coincides with the date of ovulation, since the egg remains viable only for the first day after leaving the follicle. Another issue is that few women can accurately determine the day of ovulation - only ultrasound control will show this with absolute accuracy.

The second point worth knowing is that the date of sexual intercourse will not always be the date of conception. Why? Because spermatozoa remain viable in the uterus for 4-7 days, which means that pregnancy can occur even a week after sexual contact.

How then to determine the day of pregnancy? Here are some methods.

Early ultrasound.

If ultrasound is done for up to 7 weeks, then the date of conception can be determined most accurately, with an error of 2-3 days. During this period, the embryo develops proportionally and its size is approximately the same in all women. At later dates, the size of the fetus can vary greatly, so it will be almost impossible to calculate the exact day of conception.
Last menses.

This method is quite accurate, but only if you have a stable, regular cycle. To determine the date of birth, you need to add 280 days to the day of the last menstruation. To simplify the calculation, you can use the following formula: subtract three months from the month of the last menstruation, and add 7 days to the day of the last menstruation.
First fetal movement.

Not the most accurate method, but still helps to determine the approximate gestational age. Usually, women begin to feel the movement of the baby at 18-20 weeks. Thin and multiparous women can feel the movement of the fetus as early as 16 weeks.

So, as you can see, the most reliable ways to determine the exact date of pregnancy is the day of ovulation and ultrasound in the early stages. That is why it is important not to delay with an ultrasound and visit a doctor as soon as possible after a positive result of a rapid pregnancy test. The best way to do this in a comfortable atmosphere is to choose our medical center. Here are friendly and highly qualified specialists who will answer all your questions.

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