During pregnancy, the placenta supports the developing fetus and can naturally vary in size and shape. Hearing a descriptive term like “long placenta” during an ultrasound can be confusing. This term is not a formal diagnosis but a way for a sonographer to describe the placenta’s appearance. Understanding what these variations in shape might signify can help clarify any concerns.
What Is a Long Placenta?
The term “long placenta” describes a placenta that appears stretched out, thin, or spread over a larger-than-usual area of the uterine wall. It is a description of the organ’s morphology, not a specific medical condition. An ultrasound might reveal an elongated shape that corresponds to one of several recognized placental variations.
One such variation is a bilobed placenta, where the organ is separated into two distinct lobes connected by a thin bridge of tissue where the umbilical cord attaches. Another instance is placenta membranacea, a rare condition where chorionic villi cover a much larger uterine surface than normal. This results in a very thin, widespread placental structure.
Causes of an Unusually Shaped Placenta
The development of an unusually shaped placenta is often linked to conditions within the uterus at implantation. The placenta forms in a round, disc-like shape. If the embryo implants in an area with a less robust blood supply, the placenta may spread out to increase its surface area, seeking more vascularized tissue to support the pregnancy adequately.
Certain factors can contribute to these suboptimal uterine environments. Previous uterine surgeries, such as a Cesarean section or a dilation and curettage (D&C), can leave scar tissue on the uterine wall. Since scar tissue is not as vascular as the normal uterine lining, the placenta may grow around it, leading to an elongated or lobed shape. Conditions like adenomyosis or the presence of uterine fibroids can also affect where the embryo implants and how the placenta develops.
Pregnancy Management and Potential Complications
An abnormally shaped placenta requires careful monitoring because its structure can affect its function and the delivery process. A thin and widespread placenta membranacea may not transfer nutrients and oxygen as efficiently, potentially leading to fetal growth restriction. There is also a heightened risk of placenta previa, where the placenta covers the cervix, which can cause bleeding during pregnancy. Both bilobed and membranous placentas are associated with an increased chance of vasa previa, a serious condition where fetal blood vessels run near the internal opening of the cervix, unprotected by placental tissue or the umbilical cord.
A primary concern with these placental shapes is the risk of complications after delivery. Because the placenta covers a larger surface area or is divided into lobes, a piece may be left behind in the uterus after childbirth. This complication, known as a retained placenta, can prevent the uterus from contracting properly and lead to significant postpartum hemorrhage. Due to these risks, a specialized birth plan is often developed to manage delivery safely.
Management focuses on diligent surveillance throughout the pregnancy. Your healthcare provider will likely recommend more frequent ultrasounds to monitor the baby’s growth, assess placental blood flow using Doppler studies, and pinpoint the exact location of the umbilical cord insertion. As the due date approaches, non-stress tests may be used to check on the baby’s well-being. This close observation allows the medical team to detect any potential issues early and ensure the best possible outcome for both mother and baby.