A FUPA, short for “fat upper pubic area,” is caused by fat accumulation in the mons pubis, a triangular pad of fatty tissue that sits over the pubic bone. Every woman has this fat pad. It’s a normal part of anatomy. But several factors determine how prominent it becomes: genetics, hormones, pregnancy, aging, weight changes, posture, and occasionally an underlying medical condition. Usually it’s a combination of these, not just one.
The Anatomy Behind It
The mons pubis is essentially a dome-shaped cushion of fat overlying the front of the pubic bone. It extends from the lower abdomen down to the labia and is bounded on the sides by the inguinal folds near your hip creases. What makes this area prone to fullness is its structure: the fat here is organized into two distinct layers separated by a sheet of connective tissue. The superficial layer contains tightly packed small fat lobules, while the deeper layer holds larger, more loosely organized fat compartments. This two-layer system is a direct continuation of the abdominal fat layers above it, which means changes in your lower belly often show up here too.
Genetics and Where Your Body Stores Fat
Your genes play a major role in determining where fat accumulates on your body. Research has identified that the genetic signals controlling how much fat you carry overall are different from those controlling where that fat goes. The genes linked to fat distribution are involved in how subcutaneous fat tissue functions at a local level, including how fat cells grow, break down, and store lipids in specific regions.
Sex chromosomes also matter. Studies in mice show that XX chromosomes (the female pattern) are associated with more subcutaneous fat storage compared to XY chromosomes, which aligns with why women tend to carry more fat in the lower body, hips, and pelvic region. If your mother or grandmother carried fullness in the lower abdomen and pubic area, you’re more likely to as well, regardless of your overall body size.
Fat tissue expands in two ways: existing fat cells get larger (hypertrophy), or new fat cells are created (hyperplasia). Some women simply have more fat cells concentrated in the mons pubis region from the start. This is genetically determined and largely outside your control.
Hormones and Stress
Estrogen directs fat toward the lower body throughout a woman’s reproductive years. This is why the mons pubis, hips, and thighs tend to accumulate fat more readily in women than in men. But estrogen isn’t the only hormone involved.
Cortisol, the body’s primary stress hormone, has a documented connection to abdominal fat storage. Women with higher waist-to-hip ratios secrete significantly more cortisol in response to stress compared to women who carry less abdominal fat. The relationship appears to go both ways: chronic stress drives cortisol up, cortisol promotes fat storage in the midsection, and that pattern reinforces itself over time. Since the mons pubis is anatomically continuous with the lower abdominal wall, it’s part of this same fat storage zone.
Pregnancy and C-Section Scarring
Pregnancy causes the body to deposit extra fat in the lower abdomen and pelvic area to support the growing baby. After delivery, this fat doesn’t always redistribute evenly, and the mons pubis can remain fuller than it was before pregnancy.
Cesarean delivery adds another layer. A common postoperative change called a “cesarean apron” or “cesarean shelf” occurs when the connective tissue layer between the two fat compartments of the abdominal wall isn’t fully closed during surgery. When this tissue is left open, the edges retract and create a gap. Deep fat pushes upward through that gap into the superficial layer, creating a bulge above the scar. At the same time, the scar tissue below tethers the mons pubis and prevents its fat from migrating naturally upward. The result is a protruding mons pubis sitting below an indented scar line, which is the distinctive “shelf” many women notice after a C-section.
Abdominal muscle separation, called diastasis recti, is another postpartum contributor. Studies estimate it affects anywhere from 21% to 54% of postpartum women, depending on how it’s measured. When the abdominal muscles separate along the midline, they lose their ability to hold the lower belly flat, which can push the entire lower abdominal area, including the mons pubis region, outward.
Menopause and Aging
The hormonal shift at menopause causes a measurable change in how fat behaves throughout the body. When natural estrogen production drops, fat cells in the subcutaneous layer (the fat just under your skin) become enlarged and inflamed. The tissue develops more fibrosis and reduced oxygen supply. These changes make subcutaneous fat less functional as a storage site, so the body begins redirecting fat to deeper visceral deposits around the organs and to other areas of the trunk.
For the lower abdomen and mons pubis, this means a combination of effects. Some women notice the area gets fuller as fat redistributes toward the midsection. Others find that the skin and tissue in this region loses firmness as collagen and elastin decline with age, making existing fat more visible or saggy even without actual weight gain.
Weight Changes and Loose Skin
The mons pubis is one of the most stubborn areas for fat loss. Even after significant weight loss, fat in this region often remains largely intact. This is partly because the area has a dense concentration of fat cells and partly because of how the two-layer fat system resists mobilization.
Losing more than 100 pounds frequently results in excess skin that hangs over the pubic area and upper thighs, a condition called panniculus. This is different from fat accumulation. With a true FUPA, the fat itself is pronounced and firm. With loose skin after weight loss, the tissue drapes over the area and feels softer. Many women after major weight loss have both: residual fat in the mons pubis plus an overhanging skin fold from the lower abdomen.
Posture Can Make It Look Worse
An anterior pelvic tilt, where the front of the pelvis tips forward and downward, exaggerates the curve of the lower back and pushes the belly forward. This postural pattern is common in women who sit for long hours, wear high heels frequently, or have weak core muscles. It doesn’t create fat in the mons pubis, but it can make existing fullness far more visible by changing the angle at which your lower abdomen and pelvic area are presented. Correcting the tilt through core strengthening and hip flexor stretching can noticeably reduce the appearance of a FUPA without any actual fat loss.
When It Could Be a Medical Condition
In some cases, persistent or worsening fullness in the lower body points to lipedema, a condition that causes abnormal fat buildup that gets worse over time. Lipedema most commonly affects the buttocks, thighs, and calves, but Type I lipedema specifically involves fat accumulation between the belly button and hips, which includes the mons pubis region. The fat from lipedema doesn’t respond to diet or exercise the way typical body fat does, and it can eventually lead to lymphatic blockages that cause additional fluid retention. If the fullness in your lower body seems disproportionate to the rest of you, feels painful or tender to the touch, or bruises easily, lipedema is worth investigating.