How Fundus of the Uterus Affects Pregnancy

What Is the Fundus of the Uterus?

The fundus is the top, dome-shaped portion of the uterus. It sits directly opposite the cervix, which forms the lower opening of the uterus leading to the vagina. If you picture the uterus as an upside-down pear, the fundus is the broadest, uppermost section located above where the fallopian tubes connect on either side.

Where Is the Fundus Located?

The fundus sits high in the pelvic area, positioned slightly forward over the urinary bladder. Because of its location at the very top of the uterine cavity, changes in the size or shape of the fundus can affect surrounding organs in the abdomen and pelvis.

The Three Layers of the Uterine Fundus

Like the rest of the uterine wall, the fundus is composed of three distinct layers of tissue:

• Perimetrium: The thin, protective outer membrane that covers the exterior of the uterus.
• Myometrium: The thick, muscular middle layer. This tissue gives the uterus its strength and is where fibroid tumors develop.
• Endometrium: The inner mucous lining that thickens each month during your menstrual cycle and sheds during your period.

What Does the Fundus Do?

While the fundus works in tandem with the rest of the uterus, its unique position makes it vital for several key reproductive functions:

• Pregnancy Monitoring: During pregnancy, doctors and midwives measure “fundal height”—the distance from your pubic bone to the top of the fundus. This simple measurement helps track your baby’s growth, position, and gestational age.
• Contractions and Labor: The thick muscle fibers in the myometrium of the fundus drive uterine contractions. During labor, contractions start in the fundus and push downward to help guide the baby toward the birth canal.
• Placenta Attachment: The fundus is one of the most ideal spots for the placenta to attach during early pregnancy. A “fundal placenta” sits securely at the top of the uterus, supporting healthy fetal development.

What Are Fibroids in the Fundus of the Uterus?

When benign (noncancerous) tumors develop from the smooth muscle tissue in the top portion of the uterus, they are called fundal fibroids. These growths can range in size from tiny seedlings to large, heavy masses that expand the upper abdomen.

Because the fundus has a thick muscular wall, fibroids can grow in different directions and locations. Different types of fibroids include:

Symptoms of Fundal Fibroids

Small fundal fibroids may not cause any noticeable issues at first. However, as fibroids absorb nutrients through the blood vessels feeding them, they can enlarge and place pressure on nearby structures.

Depending on their size and depth, fundal fibroids can trigger a range of painful or disruptive symptoms:

• Heavy Menstrual Bleeding: Unusually heavy periods, long menstrual cycles, or passing large blood clots.
• Pelvic Pressure and Pain: A constant feeling of fullness, aching, or heaviness in the lower abdomen or pelvic region.
• Lower Back and Abdominal Pain: Large fundal fibroids can press against lower back muscles or surrounding abdominal organs.
• Abdominal Distension: Significant growth in the upper uterus can cause the abdomen to expand, making you feel or look bloated.
• Fatigue and Anemia: Frequent or excessive blood loss during periods can lead to iron deficiency (anemia) and chronic tiredness.
• Fertility and Pregnancy Concerns: Submucosal or large intramural fundal fibroids can distort the shape of the uterine cavity, potentially impacting embryo implantation or altering fundal height measurements during pregnancy.

How Are Fundal Fibroids Diagnosed?

If you experience symptoms of fundal fibroids, a proper diagnosis is the first step toward relief. Your doctor will typically begin with a routine pelvic exam. To confirm the precise size, count, and location of fibroids in the fundus, advanced imaging tests are used:

• Ultrasound: A non-invasive scan that uses sound waves to map out the uterus and identify muscular growths.
• Magnetic Resonance Imaging (MRI): A detailed imaging test that provides a clear, high-resolution view of the uterine tissue layers, helping specialists determine the best non-surgical approach.

Nonsurgical Relief with Uterine Fibroid Embolization (UFE)

If you have been diagnosed with symptomatic fundal fibroids, major surgery is not your only option. Uterine Fibroid Embolization (UFE) is a safe, effective, minimally invasive outpatient procedure performed by an experienced interventional radiologist.^[1]

How UFE Works

1. Access: The doctor makes a tiny nick in the skin (usually at the wrist or upper thigh) to access a blood vessel.
2. Targeted Delivery: Guided by advanced real-time imaging, a thin catheter is navigated to the uterine arteries that supply blood to the fundal fibroids.
3. Embolization: Small, biocompatible particles are released to block the blood supply feeding the fibroids.
4. Shrinkage & Relief: Deprived of oxygen and nutrients, the fibroids shrink significantly over time, relieving symptoms while leaving healthy uterine tissue intact.

Because UFE is a nonsurgical procedure, it requires no general anesthesia, involves no hospital stay, and offers a much faster recovery time compared to traditional surgical operations.