Ovarian Cysts in Pregnancy

Finding an ovarian cyst during pregnancy is common, and most are harmless. The vast majority need no treatment and resolve on their own. A small number cause pain or complications and need management. This page explains the types of cysts found in pregnancy, what symptoms to watch for, and how they are managed in the UK.

Common types in pregnancy

Corpus luteum cysts are the most common in early pregnancy, supporting hormones until the placenta takes over. They usually shrink by the second trimester. Dermoid cysts, endometriomas, and other benign cysts may also be found incidentally at the booking scan. Cancer is rare, especially in reproductive years, but is considered where features are unusual. If a cyst is found in early pregnancy and is simple and small, your team will usually reassure you and arrange no further action. The corpus luteum cyst in particular is a normal part of early pregnancy and almost always resolves.

Symptoms

Most cysts cause no symptoms. Pain, bloating, or a feeling of fullness can occur if a cyst grows. Severe sudden pain may signal torsion, where the ovary twists, or rupture, both of which need urgent assessment. Contact your maternity unit or 111 if you have sudden severe abdominal pain in pregnancy. If surgery is recommended, it is usually delayed until the second trimester when the risk of miscarriage is lower and the pregnancy is more stable. Your surgeon will explain the approach and what to expect.

How cysts are monitored

Most cysts found at the 12-week scan are simply noted and rechecked. A repeat ultrasound in a few weeks confirms whether it is shrinking. Features like size, internal structure, and blood flow on Doppler help your team decide if further imaging or referral is needed. MRI may be used where ultrasound is unclear, avoiding radiation. Rarely, a cyst may turn out to be malignant. This is uncommon in pregnancy, but if features are suspicious, you will be referred to a gynaecological oncology team for specialised assessment and management.

Treatment

Most cysts need no treatment. If a cyst is large, growing, painful, or has complex features, surgery may be offered, usually in the second trimester when risk to the pregnancy is lower. Laparoscopy is often possible. If torsion is suspected, emergency surgery is needed. Your consultant will explain the balance of watching versus operating and why. Most women with ovarian cysts in pregnancy have straightforward outcomes. The cyst is noted, monitored, and usually gone by the time of the 20-week scan or shortly after, with no impact on the pregnancy.

This page is for general information only and does not replace advice from your UK maternity or mental health team. If you are worried about your physical or mental health in pregnancy, contact your midwife, GP, or call 111. In an emergency, call 999.