Stomach pain is a common symptom of pregnancy, showing up as early as the first week after conception and recurring in different forms throughout all three trimesters. The type, location, and intensity of the pain changes as pregnancy progresses, and most of it is completely normal. That said, certain kinds of abdominal pain signal serious complications that need immediate attention.
Cramping in the Earliest Days
Before you even miss a period, a fertilized egg burrowing into the uterine wall can cause mild cramping. This implantation cramping typically happens 6 to 10 days after conception. Not everyone feels it, and when it does occur, it’s usually subtle enough to be mistaken for the start of a period. It may or may not come with light spotting.
The tricky part is timing. Implantation cramping overlaps almost exactly with when you’d expect premenstrual cramps, so it’s impossible to tell the two apart by feel alone. If you’re trying to conceive, mild cramping a week or so before your expected period is worth noting, but a pregnancy test a few days after a missed period is the only reliable way to know.
How Progesterone Disrupts Your Digestion
Once pregnancy is established, rising levels of progesterone relax smooth muscle tissue throughout your body, including the muscles that move food through your stomach and intestines. Digestion slows down significantly. The result is a collection of symptoms that can feel a lot like a persistent stomachache: bloating, gas, constipation, heartburn, and nausea.
This hormonal slowdown is responsible for many of the digestive complaints that define early pregnancy. Morning sickness gets the most attention, but the bloating and crampy, gassy discomfort can be just as constant and just as miserable. These symptoms often peak during the first trimester, ease up in the second, and sometimes return late in pregnancy as the growing uterus puts physical pressure on the digestive tract.
Second Trimester: Round Ligament Pain
Between weeks 14 and 27, a different type of pain becomes common. Two thick ligaments run from the front of the uterus down into the groin, and as the uterus grows, these ligaments stretch. The sensation is a sharp, stabbing pain on one or both sides of the lower abdomen. It tends to come on suddenly with specific movements: standing up too fast, rolling over in bed, sneezing, coughing, or laughing.
Round ligament pain is brief. It flares for a few seconds and fades. If pain in the same area is constant, worsening, or accompanied by fever or bleeding, it’s not ligament stretching and needs evaluation.
Practice Contractions vs. Real Labor
In the second and third trimesters, the uterus starts rehearsing for delivery with Braxton Hicks contractions. These “practice” contractions can be surprisingly painful and are a major source of abdominal discomfort in later pregnancy. They feel like a tightening across the belly that comes and goes without a predictable pattern.
The key differences between Braxton Hicks and actual labor contractions:
- Pattern: True labor contractions come at regular intervals and get closer together. Practice contractions are irregular.
- Intensity: True contractions steadily get stronger over time. Braxton Hicks may start strong but then weaken or stay the same.
- Location: True labor pain usually starts in the back and wraps around to the front. Practice contractions are typically felt only in the front.
- Response to rest: If lying down and drinking water makes the contractions stop, they’re not real labor.
When Stomach Pain Signals Something Serious
Most pregnancy-related abdominal pain is harmless, but a few specific patterns point to complications that require urgent care.
Ectopic Pregnancy
When a fertilized egg implants outside the uterus, usually in a fallopian tube, it causes pelvic pain and light vaginal bleeding in early pregnancy. If the tube ruptures, the pain becomes sudden and severe. Shoulder pain or a strong urge to have a bowel movement can develop if blood leaks into the abdominal cavity. Ectopic pregnancies are most commonly detected between weeks 4 and 12.
Miscarriage
Cramping during a miscarriage can feel similar to normal pregnancy cramps, but it’s typically much more intense, especially for people who don’t usually experience severe menstrual cramps. Miscarriage cramping is usually accompanied by vaginal bleeding that goes beyond light spotting.
Preeclampsia
In the second half of pregnancy, a specific type of upper abdominal pain can signal preeclampsia or a related condition called HELLP syndrome. This pain sits under the ribs on the right side. It’s easy to dismiss as heartburn, indigestion, or the baby kicking, but pain in that location that doesn’t resolve deserves prompt attention, particularly if it comes with headaches, vision changes, or sudden swelling.
Urinary Tract Infections
Pregnancy increases the risk of UTIs, and while the classic symptoms are burning with urination and frequent trips to the bathroom, some people also develop pain in their side. If a UTI spreads to the kidneys, it can cause back pain, fever, chills, and vomiting. A kidney infection during pregnancy needs treatment quickly.
Pain That Needs Immediate Attention
The CDC lists several maternal warning signs related to abdominal pain. Sharp, stabbing, or cramp-like belly pain that doesn’t go away, or pain that starts suddenly and gets worse over time, warrants immediate medical care. The same applies to belly pain combined with any of the following: vaginal bleeding heavier than spotting, fluid leaking from the vagina, a fever of 100.4°F or higher, severe nausea that prevents you from keeping fluids down for more than 8 hours, or severe pain that radiates to the chest, shoulder, or back.
Mild, intermittent cramping that comes and goes, especially in the first trimester, is one of the most common pregnancy symptoms. Pain that is constant, escalating, one-sided, or paired with bleeding follows a different pattern entirely.