From the Research
Venous lakes on prenatal ultrasound are generally not associated with adverse pregnancy outcomes, and their presence or size does not significantly impact obstetrical outcomes. According to the most recent and highest quality study 1, a retrospective cohort of patients who had fetal anatomy ultrasounds at 18-22 weeks and delivered between 2018 and 2022, found no differences in pregnancy outcomes between those with placental lakes and those without. The study classified placental lakes as small or large and excluded multiple gestations, placenta previas, and placenta accretas.
The significance of venous lakes on prenatal ultrasound can be understood by considering the following points:
- The presence of venous lakes may indicate a variation in placental development, but it is not a definitive marker for any specific pathology 2.
- The size of the placental lakes does not appear to be associated with adverse pregnancy outcomes 1.
- Other studies have investigated the prenatal diagnosis of abnormalities of the fetal venous system, including the umbilical, portal, hepatic, and caval venous systems 3, 4, 5, but these findings are not directly related to the significance of venous lakes on prenatal ultrasound.
In terms of clinical management, no specific treatment or intervention is required for isolated venous lakes, as they generally have no clinical significance for the developing fetus. However, if venous lakes are numerous or unusually large, or if they appear alongside other placental or fetal abnormalities, further evaluation may be warranted through additional imaging or follow-up ultrasounds. Parents can be reassured that isolated venous lakes are considered normal variants rather than pathological findings.