Pregnancy in humans

Baby due date - Better Health Channel

Summary

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The unborn baby spends around 38 weeks in the uterus, but the average length of pregnancy, or gestation, is counted at 40 weeks.
Pregnancy is counted from the first day of the woman’s last period, not the date of conception which generally occurs two weeks later.
Since some women are unsure of the date of their last menstruation (perhaps due to period irregularities), a baby is considered full term if its birth falls between 37 to 42 weeks of the estimated last menstruation date.

The unborn baby spends around 37 weeks in the uterus (womb), but the average length of pregnancy, or gestation, is calculated as 40 weeks. This is because pregnancy is counted from the first day of the woman’s last period, not the date of conception which generally occurs two weeks later, followed by five to seven days before it settles in the uterus. Since some women are unsure of the date of their last menstruation (perhaps due to period irregularities), a pregnancy is considered full term if birth falls between 37 to 42 weeks of the estimated last menstruation date.

A baby born prior to week 37 is considered premature, while a baby that still hasn’t been born by week 42 is said to be overdue. In many cases, labour will be induced in the case of an overdue baby.

The average length of human gestation is 280 days, or 40 weeks, from the first day of the woman’s last menstrual period. The medical term for the due date is estimated date of confinement (EDC). However, only about four per cent of women actually give birth on their EDC. There are many online pregnancy calculators (see Baby due date calculator that can tell you when your baby is due, if you type in the date of the first day of your last period.

A simple method to calculate the due date is to add seven days to the date of the first day of your last period, then add nine months. For example, if the first day of your last period was 1 February, add seven days (8 February) then add nine months, for a due date of 8 November.

Determining baby due date

Irregular menstrual cycles can mean that some women aren’t sure of when they conceived. Some clues to the length of gestation include:

Ultrasound examination (especially when performed between six and 12 weeks)
Size of uterus on vaginal or abdominal examination
The time fetal movements are first felt (an approximate guide only).

Pregnancy ultrasound

A pregnancy ultrasound is a non-invasive test that scans the unborn baby and the mother’s reproductive organs using high frequency sound waves. The general procedure for a pregnancy ultrasound includes:

The woman lies on a table.
A small amount of a clear, conductive jelly is smeared on the woman’s abdomen.
The operator places the small hand-held instrument called a transducer onto the woman’s abdomen.
The transducer is moved across the abdomen. The sound waves bounce off internal structures (including the baby) and are transmitted back to the transducer. The sound waves are then translated into a two-dimensional picture on a monitor. The mother doesn’t feel or hear the transmission of the sound waves.
By measuring the baby’s body parts, such as head circumference and the length of long bones, the operator can estimate its gestational age.

The diagnostic uses of pregnancy ultrasound

Apart from helping to pinpoint the unborn baby’s due date, pregnancy ultrasounds are used to diagnose a number of conditions including:

Multiple fetuses
Health problems with the baby
Ectopic pregnancy (the embryo lodges in the fallopian tube instead of the uterus)
Abnormalities of the placenta such as placenta praevia, where the placenta is positioned over the neck of the womb (cervix)
The health of the mother’s reproductive organs.

Premature babies

A baby born prior to week 37 is considered premature. The odds of survival depend on the baby’s degree of prematurity. The closer to term (estimated date of confinement, or EDC) the baby is born, the higher its chances of survival - after 34 weeks gestation with good paediatric care almost all babies will survive.

Premature babies are often afflicted by various health problems, caused by immature internal organs. Respiratory difficulties and an increased susceptibility to infection are common.

Often there is no known cause for a premature labour; however, some of the maternal risk factors may include:

Drinking alcohol or smoking during pregnancy
Low body weight prior to pregnancy
Inadequate weight gain during pregnancy
No prenatal care
Emotional stress
Placenta problems such as placenta praevia
Various diseases such as diabetes and congestive heart failure
Infections such as syphilis.

Overdue babies

Around five out of every 100 babies will be overdue, or more than 42 weeks gestation. If you have gone one week past your due date without any signs of impending labour, your doctor will want to closely monitor your condition. Tests include:

Monitoring the fetal heart rate
Using a cardiotocograph machine
Performing ultrasound scans.

The placenta starts to deteriorate after 38 weeks or so, which means an overdue baby may not get enough oxygen. An overdue baby could also grow too large for vaginal delivery. Generally, an overdue baby will be induced once it is two weeks past its expected date. Some of the methods of induction include:

Vaginal prostaglandin gel - to help dilate the cervix
Amniotomy - breaking the waters, sometimes called an artificial rupture of membranes (ARM)
Oxytocin - a synthetic form of this hormone is given intravenously to stimulate uterine contractions.

Where to get help

Your doctor
Your obstetrician
Midwife or childbirth educator

Things to remember

The unborn baby spends around 38 weeks in the uterus, but the average length of pregnancy, or gestation, is counted at 40 weeks.
Pregnancy is counted from the first day of the woman’s last period, not the date of conception which generally occurs two weeks later.
Since some women are unsure of the date of their last menstruation (perhaps due to period irregularities), a baby is considered full term if its birth falls between 37 to 42 weeks of its estimated due date.

Common concerns and discomforts: overdue baby, Mother’s Bliss, UK.
Going Overdue, 2001, Centre for Reproduction and Minimally Invasive Surgery.
Premmie-L FAQ and advice sheets, Parents of Premature Babies Inc.(Preemie-L). More information here.
Pregnancy: what to expect when it’s past your due date, Family Doctor, USA.
Ultrasound, Women Health Information, Royal Women’s Hospital, Melbourne. More information here.

This page has been produced in consultation with and approved by:

Stages of pregnancy | Office on Women's Health

Pregnancy lasts about 40 weeks, counting from the first day of your last normal period. The weeks are grouped into three trimesters.(TREYE-mess-turs) Find out what's happening with you and your baby in these three stages.

First trimester (week 1–week 12)

During the first trimester your body undergoes many changes. Hormonal changes affect almost every organ system in your body. These changes can trigger symptoms even in the very first weeks of pregnancy. Your period stopping is a clear sign that you are pregnant. Other changes may include:

Extreme tiredness
Tender, swollen breasts. Your nipples might also stick out.
Upset stomach with or without throwing up (morning sickness)
Cravings or distaste for certain foods
Mood swings
Constipation (trouble having bowel movements)
Need to pass urine more often
Headache
Heartburn
Weight gain or loss

As your body changes, you might need to make changes to your daily routine, such as going to bed earlier or eating frequent, small meals. Fortunately, most of these discomforts will go away as your pregnancy progresses. And some women might not feel any discomfort at all! If you have been pregnant before, you might feel differently this time around. Just as each woman is different, so is each pregnancy.

Second trimester (week 13–week 28)

Most women find the second trimester of pregnancy easier than the first. But it is just as important to stay informed about your pregnancy during these months.

You might notice that symptoms like nausea and fatigue are going away. But other new, more noticeable changes to your body are now happening. Your abdomen will expand as the baby continues to grow. And before this trimester is over, you will feel your baby beginning to move!

As your body changes to make room for your growing baby, you may have:

Body aches, such as back, abdomen, groin, or thigh pain
Stretch marks on your abdomen, breasts, thighs, or buttocks
Darkening of the skin around your nipples
A line on the skin running from belly button to pubic hairline
Patches of darker skin, usually over the cheeks, forehead, nose, or upper lip. Patches often match on both sides of the face. This is sometimes called the mask of pregnancy.
Numb or tingling hands, called carpal tunnel syndrome
Itching on the abdomen, palms, and soles of the feet. (Call your doctor if you have nausea, loss of appetite, vomiting, jaundice or fatigue combined with itching. These can be signs of a serious liver problem.)
Swelling of the ankles, fingers, and face. (If you notice any sudden or extreme swelling or if you gain a lot of weight really quickly, call your doctor right away. This could be a sign of preeclampsia.)

Third trimester (week 29–week 40)

You're in the home stretch! Some of the same discomforts you had in your second trimester will continue. Plus, many women find breathing difficult and notice they have to go to the bathroom even more often. This is because the baby is getting bigger and it is putting more pressure on your organs. Don't worry, your baby is fine and these problems will lessen once you give birth.

Some new body changes you might notice in the third trimester include:

Shortness of breath
Heartburn
Swelling of the ankles, fingers, and face. (If you notice any sudden or extreme swelling or if you gain a lot of weight really quickly, call your doctor right away. This could be a sign of preeclampsia.)
Hemorrhoids
Tender breasts, which may leak a watery pre-milk called colostrum (kuh-LOSS-struhm)
Your belly button may stick out
Trouble sleeping
The baby "dropping", or moving lower in your abdomen
Contractions, which can be a sign of real or false labor

As you near your due date, your cervix becomes thinner and softer (called effacing). This is a normal, natural process that helps the birth canal (vagina) to open during the birthing process. Your doctor will check your progress with a vaginal exam as you near your due date. Get excited — the final countdown has begun!

Your developing baby

First trimester (week 1-week 12)

At four to five weeks:

Your baby's brain and spinal cord have begun to form.
The heart begins to form.
Arm and leg buds appear.
Your baby is now an embryo and one-twenty-fifth inch long.

At eight weeks:

All major organs and external body structures have begun to form.
Your baby's heart beats with a regular rhythm.
The arms and legs grow longer, and fingers and toes have begun to form.
The sex organs begin to form.
The eyes have moved forward on the face and eyelids have formed.
The umbilical cord is clearly visible.
At the end of eight weeks, your baby is a fetus and looks more like a human. Your baby is nearly 1 inch long and weighs less than one-eighth ounce.

At 12 weeks:

The nerves and muscles begin to work together. Your baby can make a fist.
The external sex organs show if your baby is a boy or girl. A woman who has an ultrasound in the second trimester or later might be able to find out the baby's sex.
Eyelids close to protect the developing eyes. They will not open again until the 28th week.
Head growth has slowed, and your baby is much longer. Now, at about 3 inches long, your baby weighs almost an ounce.

Second trimester (week 13-week 28)

At 16 weeks:

Muscle tissue and bone continue to form, creating a more complete skeleton.
Skin begins to form. You can nearly see through it.
Meconium (mih-KOH-nee-uhm) develops in your baby's intestinal tract. This will be your baby's first bowel movement.
Your baby makes sucking motions with the mouth (sucking reflex).
Your baby reaches a length of about 4 to 5 inches and weighs almost 3 ounces.

At 20 weeks:

Your baby is more active. You might feel slight fluttering.
Your baby is covered by fine, downy hair called lanugo (luh-NOO-goh) and a waxy coating called vernix. This protects the forming skin underneath.
Eyebrows, eyelashes, fingernails, and toenails have formed. Your baby can even scratch itself.
Your baby can hear and swallow.
Now halfway through your pregnancy, your baby is about 6 inches long and weighs about 9 ounces.

At 24 weeks:

Bone marrow begins to make blood cells.
Taste buds form on your baby's tongue.
Footprints and fingerprints have formed.
Real hair begins to grow on your baby's head.
The lungs are formed, but do not work.
The hand and startle reflex develop.
Your baby sleeps and wakes regularly.
If your baby is a boy, his testicles begin to move from the abdomen into the scrotum. If your baby is a girl, her uterus and ovaries are in place, and a lifetime supply of eggs have formed in the ovaries.
Your baby stores fat and has gained quite a bit of weight. Now at about 12 inches long, your baby weighs about 1½ pounds.

Third trimester (week 29-week 40)

At 32 weeks:

Your baby's bones are fully formed, but still soft.
Your baby's kicks and jabs are forceful.
The eyes can open and close and sense changes in light.
Lungs are not fully formed, but practice "breathing" movements occur.
Your baby's body begins to store vital minerals, such as iron and calcium.
Lanugo begins to fall off.
Your baby is gaining weight quickly, about one-half pound a week. Now, your baby is about 15 to 17 inches long and weighs about 4 to 4½ pounds.

At 36 weeks:

The protective waxy coating called vernix gets thicker.
Body fat increases. Your baby is getting bigger and bigger and has less space to move around. Movements are less forceful, but you will feel stretches and wiggles.
Your baby is about 16 to 19 inches long and weighs about 6 to 6½ pounds.

Weeks 37–40:

At 39 weeks, your baby is considered full-term. Your baby's organs are ready to function on their own.
As you near your due date, your baby may turn into a head-down position for birth. Most babies "present" head down.
At birth, your baby may weigh somewhere between 6 pounds 2 ounces and 9 pounds 2 ounces and be 19 to 21 inches long. Most full-term babies fall within these ranges. But healthy babies come in many different sizes.

All material contained on these pages are free of copyright restrictions and maybe copied, reproduced, or duplicated without permission of the Office on Women’s Health in the U.S. Department of Health and Human Services. Citation of the source is appreciated.

Page last updated: February 22, 2021

How long does pregnancy last: signs, terms and stages of fetal development

https://ria.ru/20210125/beremennost-1594527284.html

How long does pregnancy last: signs, terms and stages of fetal development

How long does pregnancy last: signs, terms and stages of fetal development - RIA Novosti, 01/25/2021

How long does pregnancy last: signs, terms and stages of fetal development

Pregnancy is the period when the formation and development of the fetus in the mother's body. About signs and duration - in the material of RIA Novosti. RIA Novosti, 01/25/2021

2021-01-25T18: 38

Health-Society

Pregnancy

Women

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MOSCOW, January 25 - RIA Novosti. Pregnancy is a period when the formation and development of the fetus in the mother's body. About the signs and duration - in the material of RIA Novosti. Signs of pregnancy After conception, anatomical, physiological and hormonal changes occur in the body of a woman. There are a number of signals that may indicate pregnancy. Among the presumptive signs can be distinguished: - vomiting and nausea; - drowsiness; - aversion to certain smells; - frequent mood swings; - tearfulness; - dizziness. Also, a woman may experience frequent urination, an increase in the mammary glands. The most obvious indicator is the cessation of menstruation. Most often, pharmacy tests are used to determine pregnancy. Although they are reliable, they do not provide complete information. “A pregnancy test is one of the likely signs,” added Svetlana Ivanova. - He can tell that the patient is pregnant, but at the same time, he will not show whether this is a uterine or ectopic pregnancy. This can only be determined by ultrasound.” How many weeks does a woman's pregnancy last? The expert answered the question about the pregnancy rate in weeks. According to her, pregnancy lasts 40 weeks, that is, ten obstetric months or nine calendar. Embryonic periodFrom the moment of fertilization, the embryonic period lasts until the tenth week of the obstetric period. At this time, the formation and development of the fetus in the mother's body begins. In particular, germ layers are formed in the embryo first, then tissues, organs and the placenta. During this period, the fetus increases to three centimeters, but it still does not resemble a baby, but only over time acquires the appropriate features. The fetal period The fetal period lasts from the 11th week of the obstetric period and ends with childbirth. At this time, the active growth of the fetus occurs, its proportions change, all organ systems begin to develop. In addition, the fetus begins to move in the womb. Physiological changes in the mother-fetus system Since the onset of pregnancy, two closely interconnected systems are formed. Firstly, maternal, which provides the fetus with everything necessary, and, secondly, the functional system of the fetus. Significant changes take place in the mother's body. During pregnancy, a woman needs to receive vitamins, as the need for them increases. Therefore, the body needs one and a half times more zinc, iodine, vitamins B6 and B12. Lack of vitamins can affect the duration of pregnancy.

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health - society, pregnancy, women

Health - society, pregnancy, women

MOSCOW, January 25 - RIA Novosti . Pregnancy is a period when the formation and development of the fetus in the mother's body. About signs and duration - in the material of RIA Novosti.

Signs of pregnancy

After conception, anatomical, physiological and hormonal changes occur in a woman's body. There are a number of signals that may indicate pregnancy. Among the presumptive signs can be identified:

30 December 2020, 15:04

Pregnancy test: when and how to do it to get the correct result

- vomiting and nausea;

- drowsiness;

- aversion to certain smells;

- frequent mood swings;

- tearfulness;

- dizziness.

Also, a woman may experience frequent urination, enlargement of the mammary glands. The most obvious indicator is the cessation of menstruation.

“Probable signs include an increase in the uterus,” Svetlana Ivanova, a teacher of obstetrics and gynecology of the highest category, told RIA Novosti. - When the doctor examines the patient, he can see the blueness of the vaginal cervix and the vagina itself. In general, the size of the uterus, shape and consistency changes.

Most often, pharmacy tests are used to determine pregnancy. Although they are reliable, they do not provide complete information.

“A pregnancy test is one of the likely signs,” added Svetlana Ivanova. - He can tell that the patient is pregnant, but at the same time, he will not show whether this is a uterine or ectopic pregnancy. This can only be determined by ultrasound.

July 3, 2020, 02:53

The gynecologist named the ideal age for the birth of the first child. According to her, the pregnancy lasts 40 weeks, that is, ten obstetric months or nine calendar months.

“In general, her term is 280 days, counting from the first day of the last menstruation,” added Svetlana Ivanova. - It is believed that timely delivery occurs from the 37th week to the 42nd. Childbirth before 37 weeks is considered premature, after the 42nd week - belated. Both are deviations from the norm.”

Embryonic period

From the moment of fertilization, the embryonic period lasts until the tenth week of the obstetric period. At this time, the formation and development of the fetus in the mother's body begins. In particular, germ layers are formed in the embryo first, then tissues, organs and the placenta. During this period, the fetus increases to three centimeters, but it still does not resemble a baby, but only over time acquires the appropriate features.

January 19, 2021, 20:07

What you need to take with you to the hospital for the child and mother: a list for 2021

Fetal period

The fetal period starts from the 11th week of the obstetric period and ends with childbirth. At this time, the active growth of the fetus occurs, its proportions change, all organ systems begin to develop. In addition, the fetus begins to move in the womb.

Physiological changes in the mother-fetus system

Since the onset of pregnancy, two closely interconnected systems are formed. Firstly, maternal, which provides the fetus with everything necessary, and, secondly, the functional system of the fetus. Significant changes take place in the mother's body.

“The level of progesterone, the main hormone responsible for gestation, increases, while estrogen decreases,” the expert explains. - They are responsible for the tone of the uterus. If there are too many hormones, a miscarriage may occur. During pregnancy, the heart, as well as the kidneys, work with increased stress. They excrete the urine of the mother and fetus. The thyroid and parathyroid glands increase in size, calcium production is disrupted, so pregnant women often experience brittle nails, hair loss, and teeth can crumble. Because of this, it is necessary to regularly check with the dentist for the presence of caries. This is a source of infection that can lead to infection of the fetus.”

During pregnancy, a woman needs to receive vitamins, as the need for them increases. Therefore, the body needs one and a half times more zinc, iodine, vitamins B6 and B12. Lack of vitamins can affect the duration of pregnancy.

September 26, 2020, 08:00

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How long does a person's pregnancy last? | Blog

Several studies have been done on how many weeks a pregnancy lasts. The results of these studies were published in the journal Human Reproduction.

How does pregnancy begin?

The development of pregnancy in humans begins with the fertilization of a female egg by a male spermatozoon. Fertilization is possible after ovulation - the release of the egg from the ovary. Usually, ovulation occurs on the 10-16th day of the menstrual cycle (from the 1st day of the last menstruation), but can be significantly shifted. The life span of an egg is about a day, and that of a sperm cell is 3-5 days. After ovulation, the egg enters the fallopian tube, where it meets the sperm and fertilization occurs. Then, within 14 days, the fertilized egg moves into the uterus in order to implant (fix) in the uterine cavity and continue to develop.

How to calculate the due date and what affects how many weeks the pregnancy lasts?

Estimated due date is calculated by adding 280 days to the first day of your last menstrual period. However, the duration of pregnancy is influenced by the age of the mother, the time of implantation of the embryo, the weight of the mother herself at the time of birth. It was found that with every year of her life, a woman bears a child for 1 day longer. And for every “extra” 100 grams of weight at birth, we also add 1 day to the duration of pregnancy. During the study, it was also found that embryos require different times for implantation (fixation in the uterus). And those embryos that took longer to implant also require more time from implantation to birth. More precisely, the date of birth can be determined using ultrasound.

What is term pregnancy?

In obstetric practice, full-term, it is customary to consider pregnancy lasting from 37 to 42 weeks. Up to 37 weeks is a premature pregnancy, and the birth is premature, and after 42 weeks it is a post-term pregnancy, and the birth is late.

Are there methods for accurately determining the duration of pregnancy?

A team of researchers, in order to more accurately calculate the duration of pregnancy, determined the level of hormones in the urine of women who plan to become pregnant naturally, which made it possible to determine the time of ovulation and implantation of a fertilized egg. Thus, scientists found that the duration of pregnancy was no more than 268 days, that is, 38 weeks. And the duration of pregnancy itself can vary by 37 days. It was also found that previous and subsequent pregnancies lasted approximately the same length as the pregnancy that was investigated.

Based on the results of this study, it was found that there are currently few mechanisms in the world that allow you to accurately determine the date of birth and how long the pregnancy lasts. And giving the exact due date is not a good idea, because. this causes a woman’s extra anxiety if the birth does not occur on the specified date. The poet, women should be told that you will give birth around this time.

How often do women give birth on their due date?

It is statistically known that only 4% of women give birth on the expected date of delivery, and 70% within 10 days of the due date.

How is the estimated date of delivery determined at the Leleka Maternity Hospital?

In the Leleka Maternity Hospital, doctors use the first day of the last menstruation, to which we add 280 days, as well as the ultrasound diagnostic method to determine the expected date of delivery. The most accurate time to determine the gestational age on an ultrasound scan is 11-13 weeks. During an ultrasound examination, the doctor will measure the coccyx-parietal size of the fetus, and using special tables, determine the gestational age to days and, accordingly, the expected date of birth. And, if the difference between the period calculated from the first day of the last menstruation and using ultrasound is less than 5 days, then we focus on the date according to the last menstruation, and if the difference is more than 5 days, then on the date that turned out during the ultrasound examination .

What to do if the expected date of delivery has come, but the birth has not happened?

If the date of delivery has come, but the birth does not occur, there is no need to panic. Come for a consultation with the doctors of the Leleka Maternity Hospital. During this consultation, the doctor will conduct a series of studies to make sure that everything is in order with the condition of the fetus and the pregnant woman.