Pregnancy Calendar at Week 4

What's Happening with the Baby

At 4 weeks of pregnancy, the baby is tiny – measuring just 1 mm. The body is formed from three types of germ layers. The outer layer is called the ectoderm, the middle layer is the mesoderm, and the inner layer is the endoderm. Each germ layer develops into specific systems and organs in the body.

The cells of the outer layer give rise to the skin, teeth, nails, and hair. The vertebral column will form from the middle layer, which also becomes the origin of:

muscles;
blood vessels;
sex glands;
blood;
internal organs.

The inner layer will form the liver, pancreas, lungs, and digestive tract.

In addition to forming the fetus itself, cells will also form its life-supporting organs:

at the initial stage, this is the chorion – a special sac that will later develop into the placenta and nourish the fetus;
at 4 weeks, the amnion is laid down, from which the amniotic sac will form;
the yolk sac, which contains nutrients to support the baby in the early stages until the placenta starts to function fully.

A crucial stage in a child's development during the 4th week is the formation of the primitive circulatory system. At this point, the baby is already supplied with oxygen. In the villi that connect the mother's body to the fetus, primary blood vessels are formed – these vessels are responsible for oxygen transport.

Development of Twins

The development of twins has its own unique aspects, but overall, carrying twins follows all the laws of physiology. At the 4th week, the embryos are deeply embedded in the uterine endometrium, where they are protected and continue to develop successfully. If the embryos split before implantation, each baby will form its own amniotic sac and placenta. The babies can be either fraternal or identical twins. They receive their nutrition separately, so they do not compete with each other and develop according to the expected timeline.

If the fertilized egg splits after embedding in the endometrium and implantation, the children will share one placenta. The children may have their own amniotic sacs, but in some cases, when splitting occurs at the 4th week, the children share a common amniotic sac. This makes the pregnancy more vulnerable, as the condition of the children depends on each other.

Just like in a single pregnancy, at the 4th week of a twin pregnancy, the germ layers begin to form, which will develop into the major systems and organs.

What's Happening with Mom

A pregnant woman's well-being at 4 weeks doesn't always indicate pregnancy. Signs of being "in the family way" are more likely if she's expecting twins – at this stage, she may already feel typical symptoms of discomfort. If a woman takes a pregnancy test at 4 weeks, the results will be unmistakable, as the level of human chorionic gonadotropin is significantly higher, leaving no doubt about the pregnancy.

Changes in the Uterus

The uterus doesn't significantly increase in size, but there are qualitative changes in its inner lining. The villi become thicker, enveloping the embryo at the attachment site. A mucus plug begins to form in the cervical area, which protects against infection.

Chest Pain

Some women start feeling breast tenderness, soreness to the touch, and increased sensitivity as early as the 4th week. This is regulated by hormonal changes that occur during conception. It feels as if the breasts have grown a couple of sizes. The areolas may darken, and slight pigmentation might appear, although women don't always notice it.

General Condition

In the 4th week, women might feel tired, sleepy, dizzy, and have headaches. There can be apathy, sudden mood swings, or irritability – these symptoms vary from person to person. An increase in progesterone levels primarily affects a woman's digestion – causing increased gas, making the belly appear bloated, and leading to constipation and a feeling of heaviness in the abdomen. For now, these changes are due to hormones, but later they will be triggered by the growing uterus.

Back Discomfort

Very often, it's a twin pregnancy that triggers the onset of pulling back pain. Usually, these pains are moderate and disappear after changing body positions.

Sex Drive

It's natural for women to experience a decrease in sexual activity during the first few weeks of pregnancy. The embryo is very small and vulnerable, so the expectant mother's sex drive diminishes as a way to protect the baby and ensure optimal conditions for its implantation and development.

Implantation Bleeding

When the embryo embeds itself into the uterine lining, what's known as implantation bleeding can occur. You might notice a small, bright red spot on your underwear. Observant women may suspect a possible pregnancy from this sign alone. There's no danger with this type of bleeding, so there's no need to worry – it's just the blood vessels in the uterine lining getting disrupted. Once this sign appears, you can go for an ultrasound examination.

Discharge

At 4 weeks pregnant, women may notice heavy discharge. It is clear or has a whitish tint and is thick in consistency. This discharge is directly caused by hormonal changes, so there's no need to worry unless there is bleeding or cramping pain in the lower abdomen.

Medical Examination

It's still too early for a full-body medical examination at this stage. Pregnant women are not yet registered, so only a gynecologist's check-up is important. If a woman wants to confirm pregnancy as early as possible, she can not only take a pregnancy test but also undergo an ultrasound examination. High-sensitivity equipment can detect the corpus luteum and the embryo's position in the uterus to confirm pregnancy.

Challenges of Pregnancy

The 4th week is the first critical period of pregnancy because the continuation of the pregnancy depends on the successful attachment of the embryo to the uterine cavity. Complications or pathologies can manifest in a number of dangerous conditions.

Miscarriage

In some cases, the pregnancy does not continue, and the woman experiences heavy bleeding, similar to menstruation. This is a miscarriage. The fusion of the egg and sperm may occur successfully, but implantation does not happen in the 4th week, or the embryo is rejected. This can be triggered by past infectious diseases, lifting heavy objects, injuries, uterine or fetal pathologies. Sometimes, the mother's immune system perceives the embryo as a foreign body and, despite the relative health of the body, still does not allow it to develop. Often, such bleeding is perceived by the woman as a regular period, and she may not even realize she was pregnant.

Ectopic Pregnancy

One of the common complications in the 4th week of pregnancy is an ectopic pregnancy. This means that fertilization of the egg has occurred, but there is no attachment in the uterus. The embryo gets stuck in the fallopian tubes, ovaries, or abdominal cavity, but not in the uterine lining. Ectopic pregnancy usually occurs in very young girls (under 18 years old) as well as in women over 35 years old. This pathology is caused by abnormalities in the structure of the reproductive organs, inflammatory processes, adhesions, and other conditions. Unfortunately, such a pregnancy cannot be preserved, as the fetus will not survive.

Missed Miscarriage

A missed miscarriage typically occurs in the presence of maternal infectious pathologies, stress, or alcohol intoxication. It can also be triggered by heavy physical exertion, poisoning of the body with toxins, or taking teratogenic medications, but most often it is caused by genetic abnormalities in the fetus. If a missed miscarriage is suspected, the doctor will compare the size of the fetus to the expected size for the weeks of pregnancy, and if it is not growing, the pregnancy is considered unsuccessful, and the fetus is removed. Otherwise, intoxication will begin, and the fetal tissues will start to decompose.

Luteal Cyst

Pathology is found in one out of every twenty women. The cause of the cyst can be a previous abortion, hormonal imbalances, inflammatory diseases of the female reproductive organs, or improperly chosen contraceptives. It is not dangerous, and it is quite possible to carry a baby to term with a corpus luteum cyst, but the woman should be monitored by a doctor. A luteal cyst appears after ovulation if it forms incorrectly. The corpus luteum should perform its functions for the fetus until the placenta is formed. The doctor monitors the cyst, but it usually disappears on its own in the second trimester.

Infectious Diseases

The doctor usually suspects TORCH infections – toxoplasmosis, rubella, cytomegalovirus, herpes. These dangerous diseases can lead to fetal developmental defects and even provoke a miscarriage. To protect against infection, it is necessary to plan the pregnancy in advance and get vaccinated beforehand. If the pregnancy is unplanned, the woman must strictly follow preventive measures to avoid infection during pregnancy.

What You Can and Can't Do

The first weeks of fetal development are extremely important, and in the fourth week, the baby attaches to the uterine wall. Therefore, a woman should be as careful as possible and know what she can and can't do at this stage.

What Moms-to-Be CAN Do:

Take care of their health and maintain a proper sleep schedule, as this affects the immune system of the mother's body;
Take vitamin complexes recommended by their doctor;
Diversify their diet by adding natural sources of vitamins and minerals;
Spend more time outdoors, take walks before bedtime;
Lead an active lifestyle, engage in fitness, and go to the pool;
Switch to lighter work if exposed to teratogenic industrial factors;
Undergo an ultrasound examination and take the first picture of the baby.

What Moms-to-Be CAN'T Do:

Lifting heavy weights, giving your body strength training, and doing weight exercises at the gym;
Consuming alcoholic beverages, using drugs, and smoking;
Being around sick people, as chickenpox, rubella, or other infectious diseases can terminate a pregnancy;
Engaging in sexual activity is prohibited during in vitro fertilization;
Taking medications without consulting a doctor;
Using folk remedies and homeopathy without your gynecologist's knowledge;
Undergoing X-ray examinations (except in emergencies);
Contacting aggressive chemical substances;
Taking hot baths, using enemas, and douching.

Proper Nutrition

Pregnancy makes a woman change her dietary preferences and habits primarily for the successful development of the fetus. That's why doctors insist on a thorough review of the diet and the introduction of healthy foods that will provide the mother's body with essential vitamins and trace elements.

At the 4th week of pregnancy, it is recommended to:

Exclude heavy dishes that cause constipation and take a long time to digest in the stomach. Fatty foods have similar negative properties – it's better to replace them with easily digestible carbohydrates, proteins, and add fiber – seasonal vegetables and fruits;
If breakfast didn't go well and the woman experienced morning sickness, don't skip or delay eating. After half an hour, have a lighter meal – an omelet, cottage cheese, or cheese;

To combat constipation, avoid overeating protein-rich foods. Fruits, vegetables, berries, and bran bread will help form soft stools;
Upon learning about the pregnancy, don't eat for two – this can only lead to unnecessary weight gain and complicate the process of carrying and delivering the baby. A woman just needs to slightly increase and diversify her diet to provide both herself and the baby with the necessary nutrients;

Don't forget to stay hydrated – you should drink about one and a half liters of fluids a day. This can include plain water, fruit drinks, juices, and compotes.
It's important to cut out carbonated drinks, coffee, and alcohol from your diet – these can be harmful to both the mother and the baby. If you're replacing coffee with herbal tea, be cautious – some herbs can increase uterine tone, so it's best to consult your doctor beforehand and check the tea's ingredients.

Nutrition becomes especially important during pregnancy. You need to carefully review your diet, eliminate unhealthy foods, and add as many nutrient-rich foods as possible that contain vitamins and minerals beneficial for both the mother and the baby. Pay particular attention to Vitamin B9 – folic acid. It can be found in green vegetables, leafy greens, fruits, and tuna. Foods should be prepared by boiling, stewing, or steaming, and it's best to avoid fast food and store-bought ready meals.

Need for Vitamins and Minerals

In the 4th week of pregnancy, a woman needs vitamins, but not all of them are recommended. Some can have teratogenic effects and cause fetal death. Therefore, it's important not to buy vitamin complexes on your own without consulting a doctor.

Vitamin B9 (Folic Acid)

One of the most important vitamins for a woman expecting a baby. This vitamin is responsible for the formation of cells in the new organism, prevents neural tube defects, and brain abnormalities in the fetus. The daily requirement during pregnancy is between 600 to 800 mcg. Folic acid can be found in carrots, melons, apricots, legumes, whole grain bread, tuna, cod liver, and beef liver.

Vitamin E (Tocopherol)

This vitamin is essential for the intrauterine development of the fetus from the very first weeks. It activates metabolic processes, helps the woman's body get rid of harmful substances that affect the fetus (antioxidant effect of tocopherol). Tocopherol prevents miscarriage, reduces inflammation, and influences blood circulation, ensuring the fetus gets oxygen and nutrients. It can be found in peas, rose hips, meat, parsley, liver, and dairy products. The daily requirement is 10 mg.

Iron

Iron is essential for producing hemoglobin in the mother's body and for preventing anemia. Without enough iron, the fetus won't get enough oxygen, leading to oxygen deprivation, which can ultimately result in a miscarriage. You need about 20 mg of iron per day, and the dosage will be prescribed by your doctor. Iron can be found in legumes, beef liver, apricots, quince, leeks, lettuce, apples, buckwheat, and berries.

Iodine

Iodine is necessary for the normal functioning of the thyroid gland and for establishing hormonal balance. Women often don't get enough of this element, which is why most expectant mothers are found to have iodine deficiency. You can address this by adding iodine-rich foods to your diet and taking mineral supplements recommended by your doctor. The daily requirement for iodine is 200 mcg. You can get iodine from seafood and by using iodized salt instead of regular salt in your meals.

Calcium

The 4th week of fetal development is extremely important because the germ layers are forming, which will develop into the musculoskeletal system, hair, nails, and teeth. Calcium levels influence the formation of the neural tube and the child's cardiovascular system. When a mother has adequate calcium levels, she experiences less morning sickness and her cholesterol levels normalize. It's necessary to intake 1200 mg of calcium daily to meet the needs of a pregnant woman. Calcium can be obtained not only from mineral supplements but also from dairy products, black currants, gooseberries, cherries, and strawberries.

Important! You should consult with your doctor before purchasing a multivitamin complex.

Helpful Tips

If a woman is planning a pregnancy or suspects she might be pregnant, it's crucial to pay attention to her health to ensure the baby's well-being. She should avoid stress, refrain from lifting heavy objects, and most importantly, protect herself from infectious diseases, colds, and flare-ups of chronic conditions, as these situations can easily lead to a miscarriage.

Over 90% of women, according to surveys, do not desire intimacy in the first weeks of pregnancy. Therefore, the future dad should not insist on intimacy if his partner is not interested. Natural instincts to protect the future life dictate this attitude towards the sexual partner, but over time, things will get back to normal; it just requires some patience.

Exercises for Expecting Moms

It's both safe and beneficial for pregnant women to engage in physical activity, as a healthy body responds well to exercise. Specific exercises can help:

strengthen pelvic floor muscles, which can be beneficial during childbirth;
alleviate issues like constipation and hemorrhoids;
reduce the appearance of stretch marks that many women experience.

A trainer, aware of the woman's condition, will select a safe and effective exercise routine. The only contraindications for exercise are medical restrictions, such as the risk of miscarriage, IVF, or incorrect fetal positioning.

Discomforts During Pregnancy

Nausea and Vomiting

Signs of morning sickness can appear quite early for some women, even as early as the 4th week of pregnancy. Typically, the discomfort shows up in the mornings, and after breakfast, the digestive system responds with a vomiting reflex. Familiar favorite dishes that usually make up the morning meal are not well-received by the body. There's no need to worry – in a few weeks, the expectant mother's condition will stabilize, and the morning sickness will subside.

Heightened Sense of Smell

During morning sickness, women become more sensitive to smells. Common food odors can cause nausea, favorite perfumes become irritating and overly sweet, while unusual smells start to be distinctly noticeable and even somewhat pleasant. These changes are triggered by pregnancy, but after a while, when hormone levels stabilize, everything will return to normal.

Stomach Upset

At the 4th week, some women complain of stomach upset. This isn't always accompanied by morning sickness, but cramps in the lower abdomen and a sudden urge to defecate, along with softer stools, are not always comfortable for women. After some time, these surprises from the body will cease.

Gas and Bloating

As soon as pregnancy hormone levels rise, the body experiences digestive issues. Pregnant women often complain about increased gas, uncomfortable tingling in the stomach, and a feeling of fullness. The bloating will subside once the hormonal balance stabilizes.

General Deterioration of Well-being

Weakness in the 4th week, dizziness, and the desire to sleep longer become constant companions during the early weeks of pregnancy. At this stage, when the mother's body needs to successfully accept the fertilized egg, nature ensures that all energy is focused on this process. This results in signals for rest, allowing the woman to regain strength and for the pregnancy to progress successfully.

Checklist

Take a pregnancy test if your period is late;
Visit an OB-GYN to confirm the pregnancy;
Avoid alcohol and smoking;
Steer clear of stress and emotional strain;
Take vitamins recommended by your doctor;
Revamp your diet to include healthy foods;
Ensure you're not in an epidemic environment;
Avoid contact with animals;
Keep a journal to track your weight and how you feel;
Cut out caffeine, fatty foods, and simple carbs;
Balance your daily routine and get enough sleep;
Avoid contact with harmful chemicals.

1. What is my risk of miscarrying?

2. How is pregnancy calculated?

3 weeks 5 weeks