For a healthy, low-risk pregnancy, most people get two ultrasounds: one in the first trimester and one between 18 and 22 weeks. Outside of pregnancy, ultrasound frequency varies widely depending on the condition being monitored, from every six months for liver disease surveillance to a single one-time screening for certain cardiovascular risks. Here’s what to expect based on your situation.
Low-Risk Pregnancy: Two Standard Scans
The American College of Obstetricians and Gynecologists recommends at least one standard ultrasound during pregnancy, typically performed between 18 and 22 weeks. In practice, most providers also schedule a first-trimester scan, bringing the total to two for an uncomplicated pregnancy.
The first-trimester ultrasound, often called a dating scan, confirms how far along you are, estimates your due date, and checks whether you’re carrying multiples. It’s also used to determine whether twins share a placenta or amniotic sac, which affects how the pregnancy is managed later. The second scan, known as the anatomy ultrasound, is the detailed one. It examines your baby’s organs, limbs, and growth to look for structural concerns or birth defects. This is also when many parents learn the sex.
Some providers order additional scans in the third trimester to check growth or fluid levels, but these aren’t routine for healthy pregnancies. If your pregnancy is progressing normally and both standard scans look good, two is the typical number.
High-Risk Pregnancies Require Monthly Scans
When complications or pre-existing conditions are involved, the schedule changes significantly. Monthly ultrasounds are standard for a wide range of situations, including pregestational or gestational diabetes, chronic hypertension, preeclampsia, autoimmune disorders like lupus, thyroid problems, sickle cell disease, and significant heart disease. A history of stillbirth or prior growth restriction requiring early delivery also triggers monthly monitoring.
Twin and higher-order pregnancies follow the same monthly pattern regardless of whether the twins share a placenta. The scans track each baby’s growth individually and check for complications like unequal blood flow between them.
Some conditions call for a single extra scan rather than monthly monitoring. If you conceived through IVF, are 35 to 39 years old, or have a pre-pregnancy BMI of 35 or higher, guidelines recommend one additional ultrasound between 28 and 32 weeks on top of the standard two. If you’re 40 or older, that shifts to monthly scans for the remainder of pregnancy.
Substance use during pregnancy, including prescribed medications like methadone or buprenorphine, also places you in the monthly monitoring category. The goal in all these cases is to catch growth problems or changes in amniotic fluid early enough to adjust your care plan.
Fertility Treatment: 3 to 4 Scans Per Cycle
If you’re going through IVF or a medicated fertility cycle, ultrasounds happen frequently over a short window. A typical cycle involves three to four scans to track how your follicles are developing in response to stimulation medications. These are transvaginal ultrasounds spaced just days apart, often combined with blood draws to measure hormone levels. The timing of egg retrieval or insemination depends directly on what these scans show, so skipping one isn’t an option.
Liver Disease: Every 6 Months
If you have cirrhosis from any cause, guidelines recommend an abdominal ultrasound every six months to screen for liver cancer. This applies regardless of what caused the cirrhosis, whether it’s hepatitis, alcohol use, or fatty liver disease. The six-month interval is designed to catch tumors while they’re still small enough to treat effectively. Some providers combine the ultrasound with a blood test measuring a protein called AFP, though the ultrasound is the primary screening tool.
Thyroid Nodules: 6 Months to 5 Years
How often you need a follow-up ultrasound for a thyroid nodule depends on what the nodule looks like and whether a biopsy has been done. The range is wide.
Small nodules under 1 cm with suspicious features on imaging are typically rechecked in six to nine months. Cystic or spongy nodules, which carry very low cancer risk, can be monitored at 12 to 24 months without a biopsy. If a biopsy has already confirmed a nodule is benign, the first follow-up ultrasound is usually 12 to 24 months later. When that repeat scan shows no significant growth, many providers extend the interval to every three to five years.
The pattern here is reassuring: with each stable scan, the gap between appointments gets longer.
Breast Lesions: 6, 12, and 24 Months
When a mammogram or breast ultrasound finds something that looks probably benign, the standard follow-up schedule is imaging at 6, 12, and 24 months. This applies to findings classified as “probably benign” on the standardized reporting scale radiologists use. The idea is to confirm the lesion stays stable over two years before returning to routine annual screening. If it grows or changes at any check, a biopsy is the next step.
Kidney Stones: Roughly Every 6 Months
For known kidney stones that aren’t causing symptoms, ultrasound monitoring is commonly done about every six months to check whether stones have grown, moved, or multiplied. In children with asymptomatic stones, research suggests this interval may actually be more frequent than necessary, since stone size tends to change slowly over time. For many patients, extending the gap beyond six months is reasonable if earlier scans have shown stability. Your provider will adjust the schedule based on stone size and whether you’ve had complications before.
Aortic Aneurysm: One-Time Screening
Unlike most conditions on this list, screening for an abdominal aortic aneurysm is a one-time event. The U.S. Preventive Services Task Force recommends a single screening ultrasound for men aged 65 to 75 who have ever smoked (defined as 100 or more cigarettes in a lifetime). Men in that age range who have never smoked may still be offered screening selectively based on other risk factors.
For women who have never smoked and have no family history, routine screening is not recommended. For women aged 65 to 75 who have smoked or have a family history, there isn’t enough evidence yet to make a clear recommendation either way. If the one-time screen finds an aneurysm, your provider will set up a follow-up schedule based on its size.