Gallstones (cholelithiasis) are hardened deposits that form in the gallbladder, a small organ beneath the liver that stores bile. Pregnancy significantly increases the risk of developing these stones or experiencing symptomatic attacks. This heightened risk is a direct consequence of the hormonal and physiological changes the body undergoes during gestation. Understanding the mechanisms behind this increased risk and the appropriate management strategies is important for maternal and fetal health.
Hormonal Changes and Bile Composition
The surge in sex hormones during pregnancy directly alters bile composition and gallbladder function. Elevated levels of estrogen cause the liver to secrete more cholesterol into the bile. This excessive cholesterol saturation makes the bile “lithogenic,” meaning it is prone to forming crystals and hardening into stones.
High concentrations of progesterone, which relaxes smooth muscles throughout the body, impact the gallbladder. Progesterone reduces the contractility and motility of the gallbladder muscle walls. This decreased movement prevents the gallbladder from emptying completely, causing bile to sit and become concentrated, a condition known as bile stasis.
The combination of cholesterol-supersaturated bile and the sluggish emptying of the gallbladder creates an environment highly conducive to gallstone formation. This explains why many stones formed during pregnancy are cholesterol-based. The risk of stone formation is particularly high during the third trimester as hormone levels peak.
Identifying Symptoms and Risk Factors
The most common symptom of gallstones is an attack known as biliary colic, which occurs when a stone temporarily blocks a bile duct. This blockage causes sudden, intense pain, usually felt in the upper right quadrant of the abdomen or the upper middle part of the stomach. The pain may radiate to the right shoulder blade or the back.
These attacks often begin shortly after eating a fatty meal, which triggers the gallbladder to contract in an attempt to release bile. Accompanying symptoms include nausea, vomiting, and indigestion. If the stone causes prolonged inflammation of the gallbladder (cholecystitis), the pain becomes more severe and may last for many hours, sometimes accompanied by a low-grade fever or chills.
While hormones are the primary cause, several non-hormonal factors can compound the risk of gallstone development during pregnancy:
- A history of multiple pregnancies (high parity).
- Being overweight or obese, which independently increases cholesterol secretion into the bile.
- Having a family history of gallstones.
- Being over the age of 35.
- Experiencing rapid weight loss before pregnancy.
Management and Treatment During Pregnancy
Diagnosis relies on ultrasound, the primary and safest imaging method during pregnancy. Ultrasound is effective because it does not use radiation and clearly visualizes the stones and any associated inflammation. Once gallstones are confirmed, treatment prioritizes the well-being of both the mother and the fetus, beginning with conservative management.
A low-fat diet is often recommended to reduce the frequency and severity of attacks by minimizing the demand for the gallbladder to contract. Pain relief and adequate hydration are also part of this initial approach. In most cases of uncomplicated biliary colic, these conservative measures manage symptoms until after delivery, when hormone levels normalize and symptoms may resolve.
If a person experiences repeated, severe attacks or develops complications like acute cholecystitis or pancreatitis, surgical intervention may be necessary. Laparoscopic cholecystectomy (removal of the gallbladder) is the gold standard for symptomatic gallstones. This minimally invasive procedure is considered safest for the fetus when performed during the second trimester. Delaying treatment for serious complications carries risks of infection and inflammation that can harm both the mother and the developing baby.