4 Weeks Pregnant: Symptoms, Body Changes, Risks And Tips

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The fourth week of pregnancy is when most women find out that they are pregnant. When you are four weeks pregnant, your baby is around the size of a poppy seed and is developing in the inner lining of your womb (1). Most pregnancy symptoms are not clearly visible except for a few, such as a late period and tender breasts.

Read on to know about the signs, symptoms, changes, growth, and do’s and don’ts while you are four weeks pregnant.

Changes Occurring In The Fourth Week Of Pregnancy

As the pregnancy progresses, many changes occur in the embryo and the mother’s body.

  • Amniotic sac/outer layer around the embryo gradually develops along with the placenta.
  • Shape of the face also roughly starts to form with large circles for eyes.
  • Baby’s heart develops and beats around 65 times per minute by the end of the fourth week,
  • Blood circulation begins as the blood cells take shape (2).

Signs And Symptoms Of Pregnancy At 4 Weeks

Though the physical signs of pregnancy are not visible by the fourth week, the body undergoes various internal changes to accommodate the fetus and keep it nourished and protected. Following are the common signs and symptoms during this time (3):

  • Morning sickness due to an increased level of hormones
  • Frequent bouts of fatigue due to higher physical and emotional demands
  • Enlarged mammary glands due to increased levels of estrogen and progesterone pregnancy hormones, leading to breast tenderness
  • Darkening of the area around the areola (nipple)
  • Frequent urge to urinate and episodes of constipation as the developing fetus starts to press against the intestines
  • Mood swings due to a surge in hormone levels

The Belly At Four Weeks

Most first-time mothers don’t start showing the belly until week 12. However, if it is not your first pregnancy, you may start showing it earlier as your womb muscles are still stretched from your previous pregnancies (4).

The Do’s And Don’ts In The Fourth Week Of Pregnancy


  • Sleep well: During pregnancy, get at least eight to ten hours of sleep per day to cope with the physical and emotional demands of your body and the baby.
  • Have nutritious food: The food you eat is fuel for you and your developing baby. Hence, make healthy eating choices and maintain a balanced diet (5). You don’t need to eat for two!
  • Include folate in your diet: If you did not add folate or folic acid to your diet before getting pregnant, do so now. Consuming at least 400mcg of folate per day is important in the first trimester to help prevent two major congenital disabilities—anencephaly and spina bifida.
  • Take prenatal vitamins: Prenatal vitamins are important for maintaining good nutrition during pregnancy and for the baby’s proper growth and development (6)
  • Stay hydrated: Staying hydrated helps prevent preterm labor, kidney infection, and headaches. It also helps reduce the risk of constipation and hemorrhoids.


  • Smoke: Studies conducted by the Centers for Disease Control and Prevention (CDC) report that pregnant women who smoke may have a higher risk of miscarriage (7).
  • Drink alcohol: According to the CDC, all types of alcohol are harmful to the baby during pregnancy (8). The alcohol may pass on to the baby through the umbilical cord and cause miscarriage or physical or intellectual disabilities known as fetal alcohol spectrum disorders (FASDs).
  • Consume too much caffeine: Research suggests that consuming less than 200mg of caffeine is acceptable in the first trimester (9). However, excessive caffeine could affect the fetus’ heart rate.
  • Visit the sauna: Hot tubs or saunas increase the body’s core temperature, which may adversely affect the baby’s development and double the risk of miscarriage (5).

What To Eat

Consuming a balanced diet can help reduce nausea and constipation and aid in having a healthy pregnancy. Below are some advantageous foods for you and your baby (10).

  • Proteins: peas, nuts, beans, lean beef, pork, salmon, and trout
  • Vegetables: carrots, pumpkin, red sweet peppers, tomatoes, and spinach
  • Grains: cooked or ready-to-eat cereals
  • Fruits: bananas, mangoes, cantaloupes, prunes, apricots, oranges, and grapefruit

Potential Risks In The Fourth Week Of Pregnancy

Most cases of miscarriage or ectopic pregnancy occur in the early months after conception (11). Some common potential risks during pregnancy include

  • Miscarriage: Miscarriage in the early months of pregnancy is known as a chemical pregnancy. The most common cause of a miscarriage in the first trimester is a chromosomal abnormality (12).
  • Bleeding: Some women may experience light spotting or bleeding in the early days of pregnancy but have an overall healthy pregnancy throughout. However, any signs of bleeding or rupture of blood vessels during pregnancy should be reported to your healthcare provider to avoid complications.
  • Ectopic pregnancy: Ectopic pregnancy is common and occurs in around one in 80 pregnancies in the UK. In this condition, the fertilized egg implants itself in the fallopian tube instead of the endometrium. In the later stages of an ectopic pregnancy, the baby’s growth may severely damage the fallopian tube and cause pain and bleeding (13).

Screening Tests In The Fourth Week

Getting certain tests done in the early weeks of pregnancy can help determine pregnancy or fetal complications.

Blood tests measure the amount of pregnancy-associated plasma protein and the pregnancy hormone human chorionic gonadotrophin (hCG). Abnormal quantities of either may indicate the risk of chromosomal abnormality in the fetus (14).

Frequently Asked Questions

1. What is my risk of miscarrying?

The risk of miscarrying at four weeks of pregnancy stands at around 25% (15).

2. How is pregnancy calculated?

Pregnancy is calculated from the first day of your last menstrual period. You can also use a pregnancy calculator to calculate your approximate due date.

3. What should I avoid at four weeks pregnant?

At four weeks pregnant, you should avoid (16) (17):

  • Chemical exposure to cleaning products, mothballs, wall paints, fake tan products (containing dihydroxyacetone), and hair treatment products
  • Handling cat litter as it increases the risk of toxoplasmosis
  • Undercooked meat and eggs. They may increase the risk of contracting infections such as listeriosis and toxoplasmosis, which may lead to serious illnesses

Pregnancy is a special time for all would-be mothers. It is also a time when you undergo many physical and mental changes. Thus, it is important to take proper care of yourself and your developing baby for a healthy pregnancy and safe delivery.

Infographic: Tips To Reduce Miscarriage Risk At Four Weeks Pregnant

The 4th week of pregnancy is the initial and crucial phase of the first trimester. As you embark on your pregnancy journey, this infographic can guide you with vital things to consider during this week to prevent pregnancy loss and sustain a healthy pregnancy.

tips to reduce miscarriage risk at four weeks pregnant [infographic]
Illustration: MomJunction Design Team

Key Pointers

  • By the fourth week of pregnancy, the shape of the baby’s face and heart develops.
  • Take your prenatal vitamins and eat a well-balanced diet with folate-enriched foods.
  • Miscarriage, bleeding, and ectopic pregnancy are major concerns during this week.
  • You may need to take blood tests to measure pregnancy-associated plasma protein and hCG hormone.

  1. You and your baby at 4 weeks pregnant.
  2. Fetal development: stages of growth.
  3. The first trimester.
  4. Week-by-week guide to pregnancy.
  5. Do’s and don’ts during the first trimester of pregnancy.
  6. The ABCs of vitamins in pregnancy.
  7. Smoking During Pregnancy.
  8. Alcohol use in pregnancy.
  9. How much coffee can I drink while I’m pregnant?
  10. Nutrition during pregnancy.
  11. Early pregnancy problems.
  12. Signs of miscarriage.
  13. What is an ectopic pregnancy?
  14. Common tests during pregnancy.
  15. Miscarriage: your questions answered.
  16. Things to avoid during pregnancy.
  17. Do’s and don’ts during the first trimester of pregnancy.
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Sanjana Bhattacharjee

Sanjana did her post graduation in Applied Microbiology from Vellore Institute of Technology, India. Her interest in science and health, combined with her passion to write made her convert from a scientist to a writer. She believes her role at MomJunction combines the best of both worlds as she writes health-based content based on scientific evidence. Sanjana is trained in classical... more

Dr. Ben Abbes Taarji Hicham

Dr. Ben Abbes Taarji Hicham is a practicing obstetrician and gynecologist with over 20 years of experience. Having worked in various Moroccan hospitals, he currently runs a private practice. Dr. Hicham specializes in rejuvenation and cosmetic gynecology, medically assisted reproduction, breast and gynecological cancers, HPV diseases, hysteroscopy and laparoscopy, and hormonal disorders.