Sixth Week of Pregnancy: What to Expect

During the sixth week of pregnancy, the embryo implanted in the uterus begins to grow very rapidly and all of its organs begin to develop from primitive structures.

The most important embryonic developmental event during this sixth week is the formation of the primitive heart, which begins to beat and pump blood throughout the body of the fetus.

The expectant mother’s body also continues to undergo major changes to adapt to pregnancy. However, it is possible not to feel any pregnancy symptoms yet.

Although at the beginning of the sixth week of pregnancy the embryo is still very small (measuring about 2-4 mm), it begins to undergo major changes and to increase in size rapidly. By the end of this week, it will measure about 5-6 mm and can be seen on ultrasound.

These measurements correspond to the craniocaudal length (CCL), which is the length from the head to the end of the spine. The measurement of the legs is not taken into account, as they are bent and this could lead to a bias in the measurement.

In addition, this little baby’s heart is also beginning to form during this 6th week of pregnancy. It has only two blood vessels, but it is already starting to beat very vigorously.

The fetal heart beats very fast, much faster than in an adult. In the first ultrasound, it is possible to hear the heartbeat at about 150 beats, which is completely normal.

The appearance of the embryo during week 6 of pregnancy is a bit strange. Its head is very large and appears curved towards its body.

The rest of the changes that the fetus undergoes during its development are discussed below:

• The neural tube, from which the brain and spinal cord are formed, begins to close.
• In the middle part of the embryo, and intestine is outlined, the origin of the entire digestive system.
• Inside the embryo, the lungs and muscle fibers begin to form.
• The primordial of the eye and ear are formed, which are observed as black spots on both sides of the head.
• The extremities are not well seen, but small protuberances appear, which will first form the arms and then the legs.

During this embryonic stage, most of the organs of the whole body are formed. Therefore, there is a greater susceptibility to suffering malformations in the fetus if the woman follows unhealthy lifestyle habits or does not take care of herself from the beginning of her pregnancy.

The placenta has not yet fully formed, and the umbilical cord does not yet provide the nourishment necessary for the development of the fetus. This nutritional supply is provided by the vitelline vesicle, an embryonic attachment that will disappear when the placenta is formed.

The first ultrasound

The first-trimester ultrasound that confirms the pregnancy should be done from the 6th or 7th week of pregnancy. It is not advisable to do it earlier because it is possible that the embryo is not yet visible inside the gestational sac, which generates some stress in the woman thinking that something is wrong.

Most women can already visualize the embryo with an abdominal ultrasound at the sixth week, as well as hear the heartbeat of the heart that has just formed. However, there are times when the heartbeat is not heard until week 7 of pregnancy.

When it is not possible to see the embryo and/or hear its heartbeat, the woman will have to have a repeat ultrasound after one or two weeks to rule out the possibility of an anembryonic pregnancy.

It is also possible to find out at the 6-week ultrasound that the pregnancy is twins. In the case of twins, two gestational sacs will be seen in the uterus. If they are twins, that is, they result from the division of one embryo, they may be in the same sac or in two different ones.

At this time of gestation, the fetus is evolving and undergoing major changes, such as the formation of the circulatory system.

All this rapid development and growth in the womb causes the woman to feel obvious symptoms of pregnancy, such as the following:

• Morning sickness or vomiting.
• Increased tiredness and weakness
• Intolerance to some smells or tastes
• Constipation
• Darkening of the skin
• Frequent urination
• Breast tenderness and enlargement
• Appearance of cravings
• Headache
• Nasal congestion
• Excessive salivation
• Heartburn
• Constant mood swings

It is important to note that not all women have the same symptoms. In fact, some women report having no symptoms in the sixth week of pregnancy.

What does happen inside the woman’s body are changes to adapt her bone structure and organs to her new state of pregnancy.

These changes also modify, in a more or less perceptible way, the rhythm of breathing, the woman’s metabolism, blood circulation, the functioning of the liver and intestines. In addition, the change that will begin to be more significant from this week 6 onwards is the weight gain and the growth of the belly.

Tip: If you suffer from nausea and vomiting in the 6th week of pregnancy and generally in the first trimester, this is not uncommon. Often, gentle methods such as homeopathy and acupuncture or acupressure can help. Sometimes, however, the watchword is simply: hang in there! The complaints usually improve from the 12th week of pregnancy, at the latest from the 25th week – even if this still seems far away in the 6th week. Then the hormonal change is complete.

Care and recommendations

When a woman discovers she is pregnant, there are many changes she has to make in her lifestyle so as not to compromise the baby’s health or her own.

In this section, we are going to focus on recommendations to combat discomfort during the sixth week of pregnancy, as well as the most important care that a woman should take into account:

• It is important to continue taking folic acid since the embryo’s neural tube is beginning to close.
• Eat a healthy and balanced diet with legumes, fish, dairy products, meats, fruits, and cereals.
• Eliminate from the diet undercooked or raw meats, sausages, and unpasteurized milk and cheeses, in order to avoid toxoplasmosis and listeriosis.
• It is not advisable to use laxatives to combat constipation. Constipation can be combated by drinking plenty of water, exercising daily, and eating foods rich in fiber.
• If vomiting is frequent during these weeks, the woman should eat a diet based on easily digestible foods, eat 5 to 6 meals a day and drink plenty of water for hydration.
• Try not to drink too much water before going to sleep to avoid getting up several times during the night.
• Get adequate rest. If possible, it is advisable to take a short nap to be more active in the afternoon.
• Practice sports and exercise in moderation such as yoga, pilates, swimming, or walking.
• To avoid breast discomfort, it is advisable to buy a comfortable, non-wired, cotton bra.
• Give up unhealthy habits such as coffee, alcohol, tobacco, or other drugs.