Pregnant Woman Anatomy: From Conception to Delivery

Pregnancy brings many anatomical and physiological changes to a woman's body. While you may not be able to identify physiological changes, many of the anatomical changes become apparent in the later stage of pregnancy.

Female anatomy during pregnancy is associated with the growing baby in the womb. As the baby grows in size, a mother's body continues to change to accommodate the growing baby [1]. Understanding the anatomy of a pregnant woman helps an expectant mother to care for her and the baby.

In this article, we will understand a pregnant woman anatomy and what changes occur in different organs during pregnancy. The article also covers the different stages of a baby's development.

What is Meant by Pregnancy Anatomy?

Pregnancy anatomy refers to the structural and functional adaptations of a woman’s body during gestation — the period of time between conception and childbirth [2]. The changes in a female body help create a nurturing environment for the developing baby.

The most important aspects of a pregnant woman anatomy include changes in the reproductive organs, cardiovascular system, respiratory system, and musculoskeletal system [1]. All these organ systems work for a single goal, which is supporting the growth and development of the baby in the womb.

If you observe a pregnancy diagram or diagram of pregnant woman, you will be able to spot many of the pregnancy-related changes. These changes include the position of the uterus, the displacement of internal organs, and the growing baby’s location.

The Reproductive Organs in Pregnancy

Since the female reproductive organs are directly involved in the pregnancy process, the majority of anatomical changes occur in these pregnancy organs. Here is a detail on the different changes in female reproductive organs while pregnant:

1. Uterus

The uterus is the major female reproductive organ when it comes to pregnancy-related changes. It grows from the size of an orange before pregnancy to the size of a watermelon by the end of the pregnancy [3].

This excessive growth in the size of the uterus occurs to accommodate fetus in the uterus, placenta, and amniotic sac. By the end of pregnancy, the uterus pregnant may extend up to the ribcage and hold a volume of up to 5 liters. This expansion shifts other organs upward and outward, creating space for the baby.

2. Cervix

The cervix, which connects the uterus to the vagina, plays a significant role in preparing the body for pregnancy. Before pregnancy, it releases a fertility-friendly mucus to facilitate the sperm movement from the vagina into the uterus.

Even after pregnancy, it undergoes many changes, like dilation during labor, to support the pregnancy process. The mucus that the cervix releases forms a mucus plug during pregnancy to inhibit the entry of harmful pathogens into the uterus [4]. This significantly lowers the risk of infections in the baby.

3. Ovaries

Ovaries are the female reproductive organs present on the left and right sides of the uterus. These organs release an egg and fertility hormones during the menstrual cycle.

During pregnancy, not many anatomical changes occur in the ovaries, however, it continues to produce essential hormones like progesterone. This progesterone in the early days of pregnancy helps maintain the pregnancy until the placenta takes over hormone production [5].

How the Baby Grows in the Womb

It is the growth and development of the baby in the womb which causes the changes in anatomy of a pregnant body. A baby's growth in the womb involves different stages like embryo and then fetus. Many women confuse embryo vs fetus and use these words interchangeably.

However, an embryo refers to the early stage of development, typically from fertilization to the eighth week of pregnancy [6]. On the other hand, the term fetus is used from the ninth week onward, as the organs and pregnancy supporting structures start to develop in the baby.

The Three Stages of Pregnancy

To avoid confusion and a better understanding of fetal development stages, the nine-month pregnancy is divided into three trimesters [7]. These are:

• First Trimester (Weeks 1-12): During this period, the fertilized egg implants in the uterus and grows into an embryo. The embryo then starts to form major organs and structures. By week 8, the embryo becomes a fetus. Many women experience morning sickness and pregnancy fatigue during the first trimester of pregnancy.
• Second Trimester (Weeks 13-26): The size and weight of the baby increase rapidly during the second trimester. A mother usually starts to feel the movements of the baby during this time. The fetus develops bones, muscles, and functioning organs. In most cases, mothers experience relief from early pregnancy signs during the second trimester.
• Third Trimester (Weeks 27-40): During the third trimester of pregnancy, the organs mature to prepare for life outside the womb. The baby moves into the head-down position in preparation for birth. Mothers often feel more physical discomfort during this phase as the baby grows larger.

If you want a better understanding of the baby's growth in different trimesters, baby in womb picture or pictures of fetus in the womb can help.

When Does an Embryo Become a Fetus?

As discussed earlier, not many mothers understand the difference between an embryo and a fetus. This is why questions like, when does an embryo become a fetus, or when does embryo become fetus, or when is a fetus considered a baby, are common among expectant mothers.

Embryo and fetus words refer to different stages of pregnancy and the transition from embryo to fetus is a significant milestone during pregnancy [6]. When a fertilized egg implants into the uterus, it grows into an embryo. The embryo then transitions into a fetus at the end of the eighth week of pregnancy, when the baby’s basic anatomy is established.

Fetal Growth and Position

The fetus growth stages and the changes in anatomy of pregnant woman are nothing short of a marvel. By the end of the first trimester, the fetus in utero has formed all major organs. During the second trimester, the fetus in a womb grows rapidly, and its bones, muscles, and nervous system develop. In the third trimester, the baby gains weight and takes the head-down position in preparation for delivery.

If you observe a pregnant woman anatomy front perspective, you can see how the growing baby in stomach pushes other organs upward and outward. This displacement causes common pregnancy symptoms such as heartburn and shortness of breath.

Changes in Other Organs During Pregnancy

Reproductive organs are the primary pregnant woman organs that experience pregnancy-related changes, but they aren't the only ones. Pregnant anatomy also influences other organs and organ systems. These include:

1. Lungs: The growing size of uterus at 18 weeks can reach the ribcage during the last phase of pregnancy and may compress the lungs. This can lead to changes in breathing patterns and even shortness of breath in expectant mothers.
2. Heart: Studies show that the blood volume of pregnant women increases by 30% to 50% to support the growing baby in the womb [8]. The heart works harder to pump increased blood volume, and you may experience faster heartbeats.
3. Digestive system: Hormonal changes during pregnancy also impact the digestive system. High levels of progesterone during pregnancy can slow down digestion and you experience symptoms like bloating and constipation [9].
4. Bladder: As the uterus gets bigger each week in pregnancy, this increase in size presses the bladder. This can lead to frequent urination, which is a common sign in pregnancy.

The Bottom Line

The anatomy of pregnant body reflects the incredible changes that a woman's body undergoes during pregnancy. From changes in the different organs during pregnancy to the fetus in uterus, every change occurs with the goal to support the development of a healthy baby in belly.

Pregnant woman anatomy diagrams can help you understand the positioning and growth of the fetus in a womb. Such diagrams help expectant parents understand the journey from conception to birth. Keep in mind that if you are well aware of the challenges of pregnancy, either emotional or physical, you can prepare for them early on and support a healthy pregnancy.

FAQs

1. When does a fetus become a baby?

Women during their first pregnancy often confuse what is the foetus and when does a fetus become a baby. A fetus transitions into a "baby" at birth. The term "fetus" refers to the developing phase in the womb, while "baby" typically refers to the newborn after delivery.

2. How to make a baby?

A baby is made when a male sperm fertilizes a female egg. The fertilization of sperm and egg happens after sexual intercourse. The sperm travels to the egg, and when they fuse together, a baby begins to form.

Resources Used

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2. La Marca-Ghaemmaghami, P., & Ehlert, U. (2020). Gestation. In M. D. Gellman (Ed.), Encyclopedia of behavioral medicine (pp. 960–962). Springer. https://doi.org/10.1007/978-3-030-39903-0_20 
3. Normal uterus size during pregnancy. American Pregnancy Association. https://americanpregnancy.org/healthy-pregnancy/pregnancy-health-wellness/uterus-size-during-pregnancy/ 
4. Hansen, L. K., Becher, N., Bastholm, S., Glavind, J., Ramsing, M., Kim, C. J., Romero, R., Jensen, J. S., & Uldbjerg, N. (2013b). The cervical mucus plug inhibits, but does not block, the passage of ascending bacteria from the vagina during pregnancy. Acta Obstetricia Et Gynecologica Scandinavica, 93(1), 102–108. https://doi.org/10.1111/aogs.12296 
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8. Soma-Pillay, P., Nelson-Piercy, C., Tolppanen, H., & Mebazaa, A. (2016d). 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 
9. Alqudah, M., Al-Shboul, O., Al-Dwairi, A., Al-U´Dat, D. G., & Alqudah, A. (2022c). Progesterone inhibitory role on gastrointestinal motility. Physiological Research, 2, 193–198. https://doi.org/10.33549/physiolres.934824