A pregnancy due date calculator helps determine the date of delivery. The process and duration of pregnancy are not the same for all women. Studies have shown that childbirth often occurs about 40 weeks after the first day of the last menstrual period.
Calculating a due date with the date of the last menstrual period
Very few pregnant women know the exact date of fertilization of the egg. If you only have sex once during a period when you may be pregnant, you will not necessarily get pregnant at the same time. That’s why the due date calculator is based on the date of your last period instead.
Sperm may remain in the fallopian tubes for a day or two until they come in contact with the egg. After which contact, an egg cell may form. Because the exact time of ovulation and fertilization is unknown, the date of the first day of the last menstrual period is used to determine the probable time of delivery. This is a possible date because delivery can occur two weeks earlier or two weeks later than scheduled.
In women whose average menstrual cycle is 28 days, the egg’s fertilization occurs about two weeks after the first day of the last menstrual period. Thus, pregnancy is said to last between 38 and 40 weeks from the last menstrual period.
This method does not consider the actual time of your menstrual cycle or when you think you are pregnant. Using this method is more accurate in people with regular menstruation. However, in people with irregular menstrual periods and who may be suffering from problems such as polycystic ovaries or other hormonal disorders, determining the probable delivery time requires using tools such as ultrasound.
Determining the time of delivery through ultrasound
Determining the due date is sometimes difficult because of irregular menstrual periods or forgetting the time of the last menstrual period. Even in the case of a pregnant mother while breastfeeding without the start of regular menstrual periods, it is impossible to determine the estimated delivery time.
Therefore, in addition to clinical examinations, an ultrasound of the first trimester of pregnancy can be used. The ultrasound specialist estimates the gestational age by measuring the fetal body’s dimensions, such as measuring the length from head to hip of the fetus, the specific diameter of the fetal head, and the diameter of the pregnancy sac.
The first time a baby’s heartbeat is heard is around 9 or 10 weeks, although it can vary, and when you first feel fetal movements on average between 18 and 22 weeks, it can be sooner or later. These methods can help determine if the pregnancy due date calculator is correct.
Note that the accuracy of ultrasound in the first trimester of pregnancy to estimate gestational age is much higher than ultrasound of subsequent periods. If you know the date of the first day of your last period, in addition to the information that the ultrasound gives you, you can most likely calculate your date of delivery.
Diagnosis of labor time by abdominal examination
In some cases, you can also estimate your gestational age by examining your abdomen and determining the size of your uterus. This method is less accurate than the previous methods because conditions such as multiple pregnancies, oligohydramnios, polyhydramnios, and large or small fetuses can confuse the doctor.
In some cases, there is no access to ultrasound, and the mother does not know the date of her last menstrual period; this method may help determine the time of delivery. Generally, the Pregnancy due date calculator is always approximated, and few women give birth on an exact date. Your delivery may take place two weeks before or after the due date.
Pregnancy due date calculator in IVF
Many mothers use in vitro fertilization to get pregnant. Specify the IVF transfer date and add 266 days. Because your obstetrician knows exactly what day you transferred the fetus, he or she will calculate a more accurate date for delivery.
Pregnancy week by week
Once you have calculated your pregnancy date by Pregnancy due date calculator, you can make better predictions about pregnancy symptoms or fetal size. We all know that pregnancy lasts nine months, but doctors for detailed examinations divide this period into the first, second, and third trimesters of pregnancy.
For more accurate measurements, the gestational age should be determined by the week because the fetus and the mother’s body make special changes in each specific week of pregnancy. Here is a summary of fetal and maternal changes during pregnancy months.
The first trimester of pregnancy
The first trimester starts from the first week of pregnancy until the end of the 13th. In this trimester, around the fifth week of pregnancy, you will probably notice that you have a little angel on your way by not seeing your period and taking a pregnancy test.
After a while and around the eighth week of pregnancy, you can hear the heartbeat with the help of an ultrasound.
From an embryological point of view, pregnancy’s first trimester is the most important and sensitive period of your pregnancy. During this period, the structure of your baby’s body and organs is created. Most miscarriages and birth defects occur during this period. At this time, the cells of the fetal body divide and differentiate very quickly. That’s why you should care more for yourself and your fetus during the first trimester of pregnancy.
The mother’s body also undergoes major changes in the first trimester. These changes often cause various symptoms, including fatigue, breast tenderness, nausea, and frequent urination.
Second Trimester
The second trimester of pregnancy begins at the beginning of the fourteenth week and continues until the end of the twenty-seventh week of pregnancy. All fetus organs are formed at the beginning of this period. In the following weeks, they will grow and develop more.
The second trimester of pregnancy is often called the “golden period” because many unpleasant effects disappear quickly. During the second trimester, you are more likely to experience reduced nausea, better sleep patterns, and increased energy levels. However, you may experience new symptoms, such as back pain, abdominal pain, leg cramps, constipation, and heartburn.
Third Trimester
The third trimester of pregnancy begins at 28 weeks and continues until the end of 40 weeks. In the third trimester of pregnancy, especially in the last two months, the fetus is at its maximum weight. At this time, your abdomen becomes quite large and prominent. You may experience skin stretches due to excessive stretching of your skin.
You are probably very excited and anxious about the birth of your baby. Some physical symptoms you may experience during this time include shortness of breath, hemorrhoids, urinary incontinence, varicose veins, and sleep problems. Many of these symptoms are caused by an increase in the size of the uterus, which extends from about 2 ounces before pregnancy to 2.5 pounds at birth.
The bottom line
A typical pregnancy lasts 40 weeks, from the first day of a woman’s last menstrual period to the birth of a baby. In the pregnancy calendar, the stages of pregnancy are divided into three stages: the first trimester, the second trimester, and the third trimester.
The fetus undergoes many changes during these stages. In the pregnancy calendar, a missed period is often the first sign that a woman is pregnant. Using a pregnancy due date calculator is one of the easiest ways to determine what month the pregnant mother is in.
Depending on pregnancy symptoms, the date of the last menstrual period, ultrasounds, and test Arjang Naim MD provides the best and most complete care for pregnant women in Los Angeles.
Additional questions
- Is the due date usually early or late?
Most pregnant people (about 80%) give birth between 37 and 42 weeks, and about 11% have a premature birth.
- Which week is best for delivery?
Babies born too early may have more health problems at birth and later in life than babies born later. A baby needs 39 weeks in the womb because important organs like the baby’s brain, lungs, and liver need time to develop.
- Does C-section delay breast milk?
Some women find that a C-section delays breast milk production, but rest assured that the milk will eventually come. In the meantime, have a lot of skin-to-skin contact with your baby and try to breastfeed as often as possible.
- Does IVF affect the due date?
IVF due dates are usually two weeks shorter because there is no two-week buffer like a natural pregnancy. In IVF, after embryo implantation, there is no need to consider the release of the egg and ovulation of the body.
- Is abdominal pain normal in early pregnancy?
Abdominal pain is a frequent symptom in early pregnancy and is usually nothing to worry about. However, you should contact your healthcare provider if the pain is severe or persistent.
References
https://www.nhs.uk/pregnancy/finding-out/due-date-calculator/
https://www.whattoexpect.com/due-date-calculator/
https://www.babycenter.com/pregnancy-due-date-calculator
https://perinatology.com/calculators/Due-Date.htm