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As a woman reaches the fourth week of pregnancy, remarkable transformations occur within her body. During this stage, the embryo undergoes rapid development, taking shape and establishing the foundation for the various systems and structures that will support life. In this article, we will explore the significant milestones of the fourth week of pregnancy, including the formation of the embryonic structures, the role of hormones, and the physical and emotional changes experienced by the mother.

Embryonic Development

By the fourth week of pregnancy, the embryo has grown significantly and is now approximately the size of a poppy seed. This period is characterized by the formation of crucial embryonic structures that will eventually develop into various organs and systems.

  1. Neural Tube: The neural tube, which is the precursor to the brain and spinal cord, begins to close during this week. The closure of the neural tube is a critical step in ensuring the healthy development of the nervous system.
  2. Placenta: The placenta, a vital organ that connects the developing embryo to the uterine wall, starts to form. The placenta plays a crucial role in providing oxygen and nutrients to the growing fetus and removing waste products.
  3. Amniotic Sac: The amniotic sac, filled with amniotic fluid, surrounds and protects the developing embryo. It provides a cushioning effect and helps regulate temperature and fetal movement.
  4. Umbilical Cord: The umbilical cord, connecting the embryo to the placenta, begins to develop. Through the umbilical cord, the embryo receives nutrients and oxygen from the mother’s bloodstream.


Hormonal Changes

Hormonal changes continue to play a significant role in supporting the pregnancy and ensuring the embryo’s healthy development. The two main hormones involved during this stage are progesterone and human chorionic gonadotropin (hCG).

  1. Progesterone: Progesterone levels continue to rise, maintaining the thickened uterine lining and supporting the pregnancy. Progesterone also helps prevent the contractions of the uterus that could potentially lead to a miscarriage.
  2. hCG: The levels of hCG, produced by the developing embryo, continue to increase. hCG supports the corpus luteum in the ovary, ensuring the production of progesterone. It is also the hormone detected in pregnancy tests.

Physical and Emotional Changes

During the fourth week of pregnancy, the mother may experience a range of physical and emotional changes as her body adapts to the growing embryo.

  1. Breast Changes: The breasts may become more tender, sensitive, or enlarged as they prepare for breastfeeding. The veins in the breasts may become more prominent, and the areolas may continue to darken.
  2. Fatigue: Hormonal changes, along with the increased demands on the body, can lead to feelings of fatigue and exhaustion. It is important for the mother to prioritize rest and self-care during this time.
  3. Nausea and Morning Sickness: Some women may start experiencing symptoms of morning sickness, such as nausea and vomiting. Morning sickness can occur at any time of the day and may vary in intensity among individuals.
  4. Frequent Urination: The growing uterus exerts pressure on the bladder, leading to increased frequency of urination. This symptom is expected to continue throughout the pregnancy.
  5. Heightened Sense of Smell: Hormonal changes can result in a heightened sense of smell, making certain scents more intense or triggering aversions.
  6. Emotional Changes: Hormonal fluctuations can contribute to mood swings, increased emotional sensitivity, and changes in the mother’s overall emotional well-being. It is important for the mother to prioritize self-care and seek support when needed.

Aman k. Kashyap

I am a hard-working and driven medical student who isn't afraid to face any challenge. I'm passionate about my work . I would describe myself as an open and honest person who doesn't believe in misleading other people and tries to be fair in everything I do.

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