From the Guidelines
An anterior placenta is considered a normal variant in pregnancy, as the placenta can implant in various positions, including the front wall of the uterus, without affecting the health of the pregnancy or the baby's development. According to the most recent guidelines from the Society of Radiologists in Ultrasound consensus conference recommendations, published in the American Journal of Obstetrics and Gynecology in 2025 1, a normal intrauterine pregnancy (IUP) can have the gestational sac (GS) located in various positions within the uterine cavity, including off-midline or eccentric locations.
The key points to consider are:
- The placenta's position, including an anterior placenta, is one of several normal positions where the placenta can implant during pregnancy.
- Having an anterior placenta does not affect the health of the pregnancy or the baby's development, as stated in the guidelines 1.
- The position of the placenta may affect when the baby's movements are felt, with anterior placentas potentially making it harder to feel movements earlier in pregnancy.
- Ultrasounds and other prenatal tests work normally with an anterior placenta, and special monitoring is generally not needed unless the placenta is low-lying or covering the cervix (placenta previa), which is a separate issue from anterior positioning.
It is essential to note that the guidelines recommend avoiding terms that may cause confusion or raise unrealistic expectations, such as describing a pregnancy as "live" or "viable" in the first trimester 1. Instead, the focus should be on reporting cardiac activity or motion, and describing the pregnancy location as normal, abnormal, or unknown. In the case of an anterior placenta, it is considered a normal variant, and the pregnancy should be monitored accordingly.
From the Research
Definition of Anterior Placenta
An anterior placenta refers to a placenta that is located on the front wall of the uterus.
- This condition is often associated with placenta previa, where the placenta covers the cervix 2.
- The location of the placenta can be determined through ultrasonography, which is essential for preoperative planning in cases of placenta previa 2.
Normalcy of Anterior Placenta
An anterior placenta is not necessarily abnormal, as the placenta can implant anywhere in the uterus.
- However, an anterior placenta that covers the cervix, known as placenta previa, can be a cause for concern 3.
- The majority of cases of placenta previa are resolved before term, and the condition is typically identified during routine second-trimester ultrasound 4.
Risks Associated with Anterior Placenta
Women with an anterior placenta, particularly those with placenta previa, are at a higher risk of bleeding and other complications.
- The risk of placental invasion, estimated blood loss during surgery, and transfused erythrocyte volume are significantly higher in women with an anterior placenta 2.
- Key risk factors for placenta previa include prior cesarean delivery, advanced maternal age, and smoking 4.
Management of Anterior Placenta
The management of an anterior placenta depends on the presence of associated conditions, such as placenta accreta and vasa previa.
- A planned cesarean delivery is recommended in cases of placenta previa that persist into the late third trimester 4.
- Inpatient or outpatient expectant management may be considered for women with symptomatic placenta previa, depending on the severity of the condition and the presence of risk factors 5.