A Clear Picture of Womb and Uterus in Pregnancy
Many people use the words "womb" and "uterus" as if they mean different things. The uterus is a medical term that doctors and scientists use, while womb is a common term used in everyday language. Both words refer to the same organ in a woman's body that plays a main role in pregnancy [1].
The uterus, or womb, is a pear-shaped organ located in the pelvis region between the bladder and the rectum. Its primary function is to support the development of a baby during pregnancy. The organ has the ability to grow, stretch, and adapt to the needs of pregnancy [2].
In this article, we will explore the role of the uterus during pregnancy, visible changes in the uterus during pregnancy, and how the picture of womb and uterus look in the days of pregnancy.
Anatomy In the Picture of Uterus
The uterus or womb appears like an upside-down pear and is located in the lower abdomen. You can find three main parts in the uterus pictures:
- Fundus: Fundus is the top part of the uterus and it is located above the openings of the fallopian tubes. In a picture of the uterus, the fundus is the rounded, upper portion where the baby grows during pregnancy.
- Body: The largest central part of the uterus is called the body of the uterus or uterine cavity. It is the area which holds the developing baby and provides nourishment to the placenta. In a uterus photo, you can find the body as the thick, muscular part in the center.
- Cervix: The cervix is the lower part that connects the uterus to the vagina. It serves as the passage for menstrual blood and during childbirth, allowing the baby to move into the birth canal. It also facilitates the entry of sperm into the uterus during the ovulation days of a woman [3]. In womb pictures, the cervix can be seen at the bottom, linking the uterus to the vagina.
How the Uterus Accommodates Pregnancy?
When a woman becomes pregnant, the uterus undergoes a series of changes to accommodate the growing baby. Here is a step-by-step explanation of how the uterus adapts to the different stages of pregnancy:
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Hormonal Signals
With the ovulation phase of the menstrual cycle, a woman's body starts to increase the production of fertility hormones called estrogen and progesterone. These hormones prepare the uterus for pregnancy by thickening its internal layer with blood vessels and supporting tissues [4]. Experiencing insomnia early pregnancy can also be linked to hormonal shifts that affect the uterus and overall sleep quality, highlighting the interconnected nature of pregnancy symptoms.
These changes in the uterine environment facilitate the implantation of the egg after fertilization. However, if fertilization does not occur, the newly formed layer of the uterus starts to shed and is characterized by menses.
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Implantation
Fertilization occurs in the fallopian tube, not in the uterus itself [5]. After fertilization, the fertilized egg travels down to the uterus for implantation. Once the fertilized egg implants into the uterine lining, it starts to grow and develop into an embryo and then a mature fetus.
The safe and supportive environment of the uterus plays a significant role in this implantation. The body continues to produce estrogen and progesterone throughout the pregnancy to keep the uterine lining healthy.
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Uterine Growth
Since the baby is present inside the uterus, the uterus grows in size along with the baby. At the beginning of pregnancy, the uterus is about the size of a fist. By the end of pregnancy, it can expand to hold a baby that weighs several pounds.
Along with the baby, it also accommodates placenta and amniotic fluid. This remarkable growth happens gradually over the nine months of pregnancy.
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Blood Flow Increases
Studies show that women produce up to 50% more blood than normal during their pregnancy [6]. The uterus also increases its blood supply by forming new blood vessels to support the developing baby. This enhanced blood supply ensures that the baby receives enough oxygen and nutrients.
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Formation of the Placenta
The direct connection between the mother and the baby is through placenta [7]. This organ connects the mother's blood supply to the baby's blood. The placenta provides oxygen, nutrients, and hormones to the baby and removes waste products.
Womb Appearance During Pregnancy Stages
Pregnancy causes prominent changes in the size, shape, and position of the uterus. Here are some trimester-based changes in the uterus:
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First Trimester (Weeks 1-12)
In the first trimester, the uterus remains small but starts to thicken its walls. It’s located low in the pelvis, and you won't be able to tell if a woman is pregnant by looking at her womb pictures at this stage. By the end of this phase, the uterus begins to rise slightly, and a small bump in the lower abdomen starts to appear.
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Second Trimester (Weeks 13-26)
During the second trimester, the uterus grows rapidly. It moves out of the pelvis and into the abdominal cavity, making the baby bump more visible. The uterus becomes softer and more elastic to accommodate the growing baby. By 20 weeks, the top of the uterus — fundus — usually reaches the level of the belly button.
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Third Trimester (Weeks 27-40)
In the final stage of pregnancy, the uterus reaches its maximum size. It can extend all the way up to the ribcage. The shape of the uterus changes as the baby moves and grows. Near the end of pregnancy, the uterus starts to contract, which hints that it is preparing for labor and delivery [8].
What Happens to the Uterus After Delivery?
After the baby is born, the uterus does not immediately return to its original size. Instead, it goes through a process called involution [9].
Some prominent changes in this process include:
- The uterus gradually shrinks back to its pre-pregnancy size.
- Hormones like oxytocin help the uterus contract and expel any remaining tissues, which include the placenta and fetal tissues.
- On average, the uterus returns to its normal size and position after six weeks of delivery.
Uterus in Multiple Pregnancies
When a woman is pregnant with twins, triplets, or more, the uterus pregnant has to stretch even further than in a single pregnancy. This can make it grow larger and faster.
The basic changes, such as the thickening of the uterus lining or an increase in the blood supply, remain the same. However, the uterus must work harder to accommodate multiple babies, which may lead to more noticeable discomfort for the mother.
Common Problems Related to the Uterus During Pregnancy
Problems with uterus functioning before pregnancy can prevent pregnancy, while during pregnancy, these problems increase the risk of pregnancy complications.
Here are some common problems related to the uterus:
- Uterine Fibroids: It is a condition where the non-cancerous mass of tissues starts to grow in and around the uterus [10]. They can vary in size and may sometimes cause problems during pregnancy, such as pain or complications with the baby's development.
- Incompetent Cervix: Incompetent cervix happens when the cervix weakens and starts to open too early during pregnancy. This condition can increase the risk of miscarriage or premature birth.
- Placenta Previa: Placenta previa occurs when the placenta forms in a way that it covers the cervix [11]. This condition can cause bleeding during pregnancy and may require careful monitoring or a cesarean delivery to ensure the safety of both mother and baby.
- Uterine Rupture: Uterine rupture is when the wall of the uterus tears, which can happen during labor or delivery. The risk of uterine rupture is higher in women with a previous cesarean section surgery [12]. This is a rare but serious condition that can cause heavy bleeding and requires immediate medical attention.
Tips to Support Uterine Health During Pregnancy
Here are some tips that can help women support the uterine functioning and lower the risk of complications during pregnancy:
- Attend regular prenatal check-ups.
- Eat a balanced diet rich in vitamins and minerals.
- Stay hydrated to maintain healthy blood flow.
- Avoid smoking, alcohol, and harmful substances.
- Consult a doctor regarding exercise and activity levels.
Conclusion
The uterus, commonly called the womb, is a reproductive organ in a woman's body with unique properties. It has the ability to support implantation, nourish, and protect a growing baby during pregnancy.
The uterus undergoes many changes, from size to shape, to accommodate the growing baby. You can notice many of the changes in a picture of womb and uterus during the late months of pregnancy.
The uterus is also at risk of many conditions during pregnancy, which is why it is recommended to strictly follow your prenatal check-up schedule. Your doctor can guide you on your health and monitor the progress of the baby's development.
FAQs
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What happens to the uterus during the menstrual cycle?
The uterus lining starts to thicken near the ovulation days of the menstrual cycle. If fertilization occurs, this thickening facilitates the implantation of a fertilized egg. If no fertilization occurs, this lining sheds, causing menstrual bleeding.
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What are some common problems that can affect the uterus?
Some health conditions that can affect the uterus include fibroids — non-cancerous growths, endometriosis — growth of uterine tissue but outside the uterus, or even uterine cancer. These conditions can cause pain and discomfort and may also lead to miscarriages.
Resources Used
- Ameer, M. A., Fagan, S. E., Sosa-Stanley, J. N., & Peterson, D. C. (2022b, December 6). Anatomy, Abdomen and Pelvis: Uterus. StatPearls - NCBI Bookshelf. https://www.ncbi.nlm.nih.gov/books/NBK470297/
- Soma-Pillay, P., Nelson-Piercy, C., Tolppanen, H., & Mebazaa, A. (2016b). Physiological changes in pregnancy. Cardiovascular Journal of South Africa/Cardiovascular Journal of Southern Africa, 27(2), 89–94. https://doi.org/10.5830/cvja-2016-021
- Martyn, F., McAuliffe, F. M., & Wingfield, M. (2014). The role of the cervix in fertility: Is it time for a reappraisal? Human Reproduction, 29(10), 2092-2098. https://doi.org/10.1093/humrep/deu195
- Reed, B. G., & Carr, B. R. (2018, August 5). The Normal Menstrual Cycle and the Control of Ovulation. Endotext - NCBI Bookshelf. https://ncbi.nlm.nih.gov/books/NBK279054/
- Oliver, R., & Basit, H. (2023e, April 17). Embryology, Fertilization. StatPearls - NCBI Bookshelf. https://www.ncbi.nlm.nih.gov/books/NBK542186/
- Soma-Pillay, P., Catherine, P., Tolppanen, H., Mebazaa, A., Tolppanen, H., & Mebazaa, A. (2016). Physiological changes in pregnancy. Cardiovascular Journal of Africa, 27(2), 89. https://doi.org/10.5830/CVJA-2016-021
- Herrick, E. J., & Bordoni, B. (2023, May 1). Embryology, Placenta. StatPearls - NCBI Bookshelf. https://www.ncbi.nlm.nih.gov/books/NBK551634/
- Tantengco, O. a. G., & Menon, R. (2020). Contractile function of the cervix plays a role in normal and pathological pregnancy and parturition. Medical Hypotheses, 145, 110336. https://doi.org/10.1016/j.mehy.2020.110336
- Uterus Involution. (2024, May 1). Cleveland Clinic. https://my.clevelandclinic.org/health/diseases/22655-uterus-involution
- Yang, Q., Ciebiera, M., Bariani, M. V., Ali, M., Elkafas, H., Boyer, T. G., & Al-Hendy, A. (2021). Comprehensive Review of Uterine Fibroids: Developmental Origin, Pathogenesis, and Treatment. Endocrine Reviews, 43(4), 678–719. https://doi.org/10.1210/endrev/bnab039
- Placenta previa: MedlinePlus Medical Encyclopedia. (n.d.). https://medlineplus.gov/ency/article/000900.htm
- Togioka, B. M., & Tonismae, T. (2023, July 29). Uterine rupture. In StatPearls [Internet]. StatPearls Publishing. Available from https://www.ncbi.nlm.nih.gov/books/NBK559209/