Most people around the world have gallstones and among them, women are higher than men. Several clinical and epidemiological studies have found that women are more likely to get gallstones than men. This can be due to the sinking of abdominal viscera, abdominal tumors, sedentary life, pelvic inflammation, obesity, sex hormones, and pregnancy, etc.
But still, more research is needed to jump to the conclusions on why women are more prone to develop gallstones than men. However, several scientists and clinical researchers around the world from Italy, U.S, Sweden, and Germany, etc have reported five  most common reasons for gallstones in females and are:
- Estrogen & progesterone levels: The formation of gallstones in women is two times more than in men. This difference begins with puberty and continues throughout the childbearing years. This is due to the estrogen and progesterone levels, hormones that help in controlling the menstrual cycle.
Recent studies have reported that the increased risk for gallstones in women is a result of estrogen and progesterone levels.
Estrogen increases the amount of cholesterol in the bile and promotes the formation of gallstones. Progesterone will slow down the emptying of the gallbladder which makes bile to be more concentrated and lead to the development of gallstones.
- Pregnancy: Several medical professionals and scientific researchers claim that pregnancy is associated with an increase in the risk of gallstones. This can be due to the presence of high serum lipid levels during pregnancy and an increase in the levels of sex hormones [estrogen and progesterone].
All these together can decrease the rate and extent of emptying the gallbladder during pregnancy. So, the bile becomes highly concentrated, and more cholesterol builds up in the bile causing it to form gallstones.
- Smaller bile acid pool: Till before puberty, girls will have the same size of bile acid pool as in boys. But at puberty, bile in girls becomes more saturated with cholesterol and leads to a decrease in the bile acid pool size. Because of these changes, the bile acid pool is smaller in women than in men which causes an increase in the cholesterol concentration that leads to the formation of gallstones.
- Age, race & ethnicity: As age increases, the normal function of internal organs can get declined. Due to this, the liver can get affected and produces an extra amount of bile into the gallbladder. As bile increases, cholesterol accumulates and turns to hard stones called gallstones. Besides age, factors like race & ethnicity can enhance the risk of gallstone formation. This can be noticed in women more frequently than men.
One of the clinical studies says that “20% of American women develop gallstones by the age of 60”. Women between 20-60 years of age are three  times more likely to develop gallstones than men.
A Danish study reveals that the prevalence of gallstones in people aged 30 was 1.8% for men and 4.8% for women. Gallstone prevalence in people aged 60 years was 12.9% for men and 22.4% for women.
- Obese or overweight: Several studies proved that being overweight or obese can increase cholesterol levels in bile and develops gallstones.
Biologically women have a high percentage of body fat. Due to this, women may become obese over time and lead them to a higher risk of developing gallstones.
Besides the above reasons, contraceptive steroids also play an important role in women to develop gallstones. Administration of contraceptive steroids by premenopausal women can double the chances of the formation of gallstones.
Both men and women are prone to develop gallstones at any age. However, women are at higher risk [2x] of developing gallstones than men. This variation in risk of gallstone formation in women can be due to pregnancy, oophorectomy [removal of ovaries], and sex hormones like estrogen & progesterone. Adding to these, age, race, and ethnicity can be reasons for women to develop gallstones.
By maintaining good health and a sedentary lifestyle, one can reduce the chances of gallstone formation.