Ovarian torsion is a gynecological emergency involving the twisting of the ovary, and sometimes the fallopian tube, around its supporting ligaments. This twisting cuts off the organ’s blood supply, potentially leading to tissue damage. For a pregnant person experiencing acute abdominal pain, a diagnosis of ovarian torsion raises immediate questions about the health of the pregnancy. Rapid medical attention and understanding its implications are crucial for a positive outcome for both the mother and the fetus.
What Ovarian Torsion Means During Pregnancy
Ovarian torsion is the partial or complete rotation of the ovary around its vascular pedicle. This rotation initially compresses the thin-walled veins, preventing blood outflow, while thicker-walled arteries may continue to pump blood in. The resulting congestion causes the ovary to swell significantly, leading to ischemia (lack of oxygen) and eventual tissue death if not quickly corrected.
The risk of ovarian torsion is five times higher during pregnancy, occurring in approximately 5 out of every 10,000 pregnancies. This increased risk is primarily concentrated in the first trimester, typically between 6 and 14 weeks of gestation. The most common cause is the presence of an enlarged corpus luteum cyst, which is a temporary structure that produces hormones to support the early pregnancy.
As the corpus luteum grows, it increases the ovary’s size and weight, making it more prone to twisting. Hormonal changes during pregnancy also contribute by causing laxity in the ovarian supporting tissues and ligaments. This increased mobility, combined with a mass often larger than 5 centimeters, creates the mechanical conditions for torsion to occur.
How Ovarian Torsion Affects Pregnancy Outcome
The primary concern for individuals diagnosed with ovarian torsion is the potential for miscarriage. While ovarian torsion is a serious event, the direct risk of pregnancy loss stemming solely from the torsion itself is low, especially with prompt treatment. The focus of the emergency intervention is saving the ovary and managing the surgical risks to the pregnancy.
Detorsion, the procedure to untwist the ovary, has been shown not to compromise fetal well-being. However, the greatest risk to the pregnancy often comes from secondary complications related to the emergency intervention or untreated torsion. For instance, if a corpus luteum cyst is removed during first-trimester surgery, the subsequent drop in progesterone can destabilize the pregnancy.
In such cases, supplemental progesterone therapy is indicated to maintain the uterine lining and prevent miscarriage. Later in pregnancy, the main threat is the risk of premature labor induced by uterine manipulation during surgery. Surgical intervention in the second or third trimester carries a documented risk of preterm birth, necessitating careful surgical planning and prophylactic medications. One study reported a miscarriage rate of 3.5% following surgery in the first trimester, demonstrating that the risk is not overwhelmingly high.
Recognizing the Symptoms and Confirming Diagnosis
Recognizing the symptoms of ovarian torsion is the first step toward timely intervention. The most common symptom is the sudden onset of severe, unilateral pelvic or lower abdominal pain. This pain is often described as sharp and colicky, meaning it may wax and wane. The pain is frequently accompanied by severe nausea and vomiting, which can be challenging to distinguish from common morning sickness in early pregnancy.
A physical examination may reveal an enlarged, tender mass in the adnexal region. However, this can be difficult to assess due to the presence of the growing uterus.
Diagnosis relies on a high clinical suspicion combined with imaging tests, primarily a pelvic ultrasound with Doppler flow studies. The ultrasound can show an enlarged ovary with a cystic mass and sometimes a characteristic “whirlpool sign” (the twisted vascular pedicle). Doppler studies attempt to visualize blood flow, but the presence of normal flow does not definitively rule out the diagnosis, especially if the torsion is intermittent.
Urgent Management and Surgical Considerations
Ovarian torsion is a surgical emergency, and the definitive treatment is immediate surgical intervention to restore blood flow. The primary goal is detorsion (untwisting the ovary) to preserve ovarian function and fertility. Even if the ovary appears dark or ischemic, the standard of care is to untwist it, as many ovaries can recover function after blood flow is re-established.
The preferred surgical approach, particularly in the first trimester, is minimally invasive laparoscopy, which involves small incisions and a camera. Laparoscopy is associated with less trauma and a lower risk of uterine irritation, minimizing the chance of premature labor. However, as the pregnancy progresses into the second and third trimesters, the enlarged uterus may necessitate a traditional open surgery (laparotomy) to ensure the safety of both the mother and the fetus.
Continuous fetal monitoring is employed during the procedure to track the baby’s heart rate and well-being. If surgery is performed between 24 and 34 weeks of gestation, prophylactic antenatal corticosteroids may be administered to promote fetal lung maturity. The decision to proceed with surgery balances the urgent need to save the ovary against the minimization of risks to the developing fetus.