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1 week pregnancy

1 week of pregnancy


The most interesting thing about the first week of pregnancy is that there are two (weeks) of them. The start of the obstetric week is determined by the first day of a woman’s menstrual cycle, whereas the first week of embryonic development begins when the egg is fertilized. Pregnant women need to be aware of this distinction and ask their physician which week of the pregnancy they are referring to.

First obstetric week of pregnancy

The first week of menstruation can turn into the first week of pregnancy if fertilization of the egg and implantation of the fetal egg occurs in this menstrual cycle. If pregnancy does not occur in this cycle, the countdown starts again in the next cycle.

Good to know: The obstetric 1st week of pregnancy is calculated from the 1st day of the last menstrual period, and the embryonic week starts when the egg is fertilized. This means that the obstetric week precedes ovulation and fertilization. Generally, conception occurs between 2 and 3 obstetric weeks.

Woman’s body changes during 1 week pregnancy

As already mentioned, there is still no actual pregnancy at this time. All changes that occur in the female body correspond to the normal menstrual cycle. 

The 1 week pregnancy begins when the pituitary gland releases follicle-stimulating hormone (FSH) on the first day of menstruation, stimulating a follicle to form on the ovary. At the same time, the levels of estrogen and progesterone in the female’s bloodstream decrease while the amount of prostaglandin – a substance that causes uterine contractions increases.

This results in the surface of the uterus becoming loose and the layer of the endometrium exfoliates and comes out with menstrual bleeding.

After the end of menstruation, the hormonal background changes again. The growing follicle stimulates estrogen production at the end of the first week of pregnancy. Under its influence, a new endometrium begins to grow in the uterus. The body will be ready to receive a fertilized egg in about ten days.

How to determine the date of ovulation?

An ultrasound is usually prescribed at the end of the first week of pregnancy (typically on the 5th or 6th day of the cycle) if it is necessary after the menstrual bleeding has stopped.

The doctor will see the growing follicle and will be able to accurately predict the date of ovulation (the release of the egg from the follicle). Sexual intercourse on the eve of ovulation and on this day increases the chances of getting pregnant, so the results of an ultrasound scan will be useful for couples planning a baby.

Another way to calculate your ovulation date is to measure your basal body temperature. Further temperature measurement will help determine the date of implantation and the pregnancy.

Good to know: Spermatozoa(sperm): “boys” live not so long – from several hours to 1-2 days. If you want to conceive a girl, it’s worth trying somewhere three or more days before ovulation. If a boy, the day of conception should fall directly on the period of ovulation.

How to check pregnancy at 1 week

It is almost impossible to check pregnancy at 1 week. Changes in the body are too small for tests or an ultrasound machine to catch them. To get convincing evidence that you are in a position, you need to wait at least the 7th, and preferably the 10th day of pregnancy, when especially sensitive tests can already show the coveted two strips.

Pregnancy tests

At 1 week pregnancy, the test may show a dubious result.

A test in the first week of pregnancy will either give nothing or show a dubious result. Too little time has passed since conception for changes to become noticeable.

If you take a regular pharmacy test for pregnancy during the first week of your pregnancy, which requires you to urinate on a strip, it will definitely produce a negative result – it is too early. The same goes for the hCG analysis; the fluctuations in the level of human chorionic gonadotropin are so minimal that the results will be considered unreliable. This means the pregnant woman must wait until the gestational age is at least ten days old before the tests become reliable.


Do not rush to have an ultrasound diagnostic done in the first week of pregnancy since even the most modern equipment cannot visualize the fetus at this stage.

 As a rule, an ultrasound at such an early date is recommended for women with symptoms specific to an ectopic pregnancy, as it can be dangerous to exclude such a diagnosis. Therefore, a gynecologist may prescribe an ultrasound diagnostic. Unfortunately, those girls hoping to get the first pictures of their unborn child will have to wait until 2-3 weeks.

Very early signs of pregnancy 1 week

The expecting mother won’t experience anything extraordinary or out of the ordinary during the initial weeks of pregnancy before the delay. All sensations in the early stages will be akin to those she experiences during her menstrual cycle, as the 1 week pregnancy starts on the first day of her period.

For each woman, these sensations are individual, but for the majority, as a rule, the stomach pulls in the first weeks of pregnancy, there is aching pain in the lower back, and the chest becomes painful. Characterized by general malaise and sudden mood swings. A woman should consult a doctor if her stomach hurts in the first week of pregnancy.

Good to know: During menstruation, a woman’s lower abdomen hurts so much that she is forced to take painkillers. If a couple plans a pregnancy in this cycle, the expectant mother should refuse such pills.

When should you consult a specialist? For example, during menstruation, the stomach hurts so much that a woman loses her ability to work. If the pain is continuously tormenting for more than two days, the discharge becomes very profuse and does not stop even on the 5th or 7th day of menstruation.

1 week pregnancy Symptoms

If we consider the obstetric period, the very early signs of pregnancy 1 week are absent. The woman’s body on the first day just started preparing for ovulation and possible conception. Therefore, of course, the typical symptoms of pregnancy, such as toxicosis, morning sickness, breast tenderness and changes in the figure, do not bother the woman at this time. The expectant mother may encounter them starting from about 5 obstetric weeks. But here, too, everything is very individual: in some women, pregnancy symptoms are absent for a long time, while in others they appear already on the first day after conception.

Fetus, pregnancy diagnostics

At this stage, only the prerequisites for the appearance of the fetus arise, and successful fertilization, which can occur in about two weeks, depends on many factors. An ultrasound of the fetus at this time is not ready. It should be noted that even in the first days of pregnancy (meaning the embryonic period), there are no reliable ways to confirm successful conception.

It is highly unlikely to detect the presence of an embryo using ultrasound during the first few weeks of pregnancy if the 1st, 2nd, 3rd and 4th day of delay have passed.

The fetus in this study can be seen on about 5 or 7 days of delayed menstruation. The level of the hCG hormone (chorionic gonadotropin) produced in a woman’s body during pregnancy, does not increase in the early stages, so on the first day of the delay, the test may also not show two cherished strips. Positive results can be detected only from 12-14 days after the conception of a child.


Conception usually takes place around the 13th-14th day in a 28-day menstrual cycle, so a woman might not know she is pregnant. The first week of pregnancy ends around the 21st-25th day, so there is no need to consider a potential delay in her menstrual cycle yet. When the time comes, and menstruation has not appeared, it will become clear that the woman is expecting a baby.

Stomach ache

Expectant mothers often note that pain in the lower abdomen has become for them the first sign of pregnancy.

Many women experience pain before their menstrual cycle, so they may not notice any discomfort in the middle and second half of the cycle. Nonetheless, many pregnant women report that pain in their lower abdomen was their first indicator of pregnancy. This is usually felt 5-7 days before their period, signifying the end of the first week of pregnancy.

Pain, however, may have other causes, such as intestinal dysbacteriosis or disruption of its functions. Osteochondrosis, for instance, can cause pain in the lower abdomen, which may be transferred from the spine. In addition, pelvic pain may be due to adhesions formed after gynecologic surgery or cesarean section.

It is common for lower abdominal discomfort to be seen as a symptom of an ectopic pregnancy, when a fertilized egg is implanted outside of the uterine cavity, such as in the fallopian tubes, cervix, or ovary. Nevertheless, there may be no noticeable discomfort in the early stages of pregnancy. Typically, these symptoms will become more noticeable as the embryo develops, by 3-4 weeks.

Do’s and Don’ts of 1 week pregnancy

To prepare for giving birth, you need to put your lifestyle in order. This allows you to increase the likelihood of conception and create favorable conditions for embryo development.

Do’s for 1 week pregnancy

  • A woman in her 1 week of pregnancy can carry out activities that are not hazardous to her health. Examples include going for a massage, engaging in sexual intercourse, consuming fresh fruits and vegetables, etc.
  • It is recommended that a woman and her partner consult with a physician to discuss the impending pregnancy. The physician can advise how to prepare for childbirth and the necessities the baby will need post-birth.
  • Future parents need to maintain a healthy lifestyle.
  • Avoid large crowds of people and carefully follow hygiene rules to avoid getting a viral infection.
  • A balanced diet for the expectant mother should include meat, fish, dairy products, complex carbohydrates, and fresh fruits and vegetables.

Don’ts for 1 week pregnancy

  • The consumption of alcohol and drugs is prohibited, as well as the smoking of cigarettes, hookah, etc.
  • Do not take dietary supplements or medicines without consulting a doctor.
  • Do not undergo any x-ray examinations.
  • Avoid heavy physical exertion.
  • Do not work in harmful working conditions.
  • Do not abuse foods that can cause allergies (citrus fruits, honey, etc.).

Compliance with these simple recommendations will ensure the correct and full development of the fetus from the very first day. Remember that a mother should lead a healthy lifestyle in the first weeks of pregnancy and throughout the entire period of bearing a child in her stomach.

Lifestyle changes from the first week of pregnancy

At week 1 of pregnancy (3rd obstetric), it is almost impossible to detect the changes because the woman may not have realized that her body is already preparing to bear a child. The only possible sign that may arouse suspicion is implantation bleeding, which is characterized by small droplets of blood on the woman’s underwear.

At 1 week pregnancy, fertilization and implantation of the blastocyst (fertilized egg) take place in the uterine mucosa. The future fetus is minuscule, making it almost impossible to be seen on an ultrasound. Furthermore, pregnancy tests are likely to show a negative or questionable result. The hCG level at this stage fluctuates slightly, thus making it virtually impossible to detect the pregnancy through analysis at this early stage.

As the body begins to rebuild, a pregnant woman may experience symptoms easily mistaken for PMS, such as drowsiness, weakness, slight heaviness, pulling pains in the lower abdomen, and a change in taste preferences. 

It is important to pay attention to these signs and refrain from smoking, drinking alcohol, and lifting heavy objects if a woman is actively trying to conceive. It is also essential for the expectant mother to ensure she is eating healthy, drinking plenty of water, walking regularly, and limiting stress. Additionally, she should take time to enjoy her favorite hobbies and relax.

Checklist for the 1 week pregnancy

  1. Visit an obstetrician-gynecologist and, if necessary, other doctors to consult on pregnancy planning.
  2. Normalize the daily routine: sleep at least 7 hours, switch to 5 meals a day (3 main meals and 2 snacks), walk in the fresh air at least 40 minutes a day.
  3. strengthen immunity: harden, take multivitamins recommended by the doctor
  4. Accustom yourself to ventilate the workroom and apartment several times a day
  5. Replenish your home library with a book of healthy food recipes or find and bookmark several culinary sites of the same subject

Is it necessary to use protection in the first week of pregnancy?

It is not necessary to protect yourself in the early stages of pregnancy because the pregnancy has already begun. The second fertilization is interfered with by hormones that are produced after conception.

In extremely uncommon cases, a woman can still become pregnant again. This can happen if a woman simultaneously releases two eggs, which are both fertilized by different sperm with a slight timing difference. Nevertheless, it is important to understand that these cases are rare, so contraception is unnecessary after pregnancy except when a woman has sexual intercourse with various partners. 

In such a situation, she must use condoms to prevent transmitting potentially detrimental bacteria that can cause fetal development issues. If STDs are identified during the pregnancy examination via PCR analysis, they should be treated after twelve weeks to stop the fetus from becoming infected.

What should I do if I accidentally drink alcohol in the first week of pregnancy?

Alcohol consumption has a destructive impact on the growth of the fetus. Ethanol and other damaging substances obstruct the embryo’s attachment and can affect the unborn baby’s brain development. In cases where a woman drinks alcohol during the early phases (and beyond), it can lead to mental retardation, oligophrenia, and hydrocephalus in a child. 

If a woman had “accidental” and a single instance of drinking a small amount (e.g. a glass of wine), the chances of it causing considerable harm are likely minimal. However, a more serious risk is posed by medications taken during the early stages of pregnancy, which can negatively impact the growth of the fetus. Thus, a woman should consult a geneticist if she has taken any medications during the early stages of her pregnancy.