The placenta is a temporary organ that develops during pregnancy. Its main function is to deliver oxygen and nutrients from the mother’s bloodstream to the baby through the umbilical cord, while also removing waste products. The location where the fertilized egg implants in the uterine wall determines where the placenta will grow. Variations in this position are common, and the organ functions the same regardless of where it is situated.
What an Anterior Placenta Is
An anterior placenta is one that has attached to the front wall of the uterus, placing it closest to the mother’s abdomen. This placement is considered a very common and normal variation, occurring in up to half of all pregnancies.
Other common positions include a posterior placenta, which is attached to the back wall of the uterus, or a lateral placement on either the left or right side. Its exact location is typically identified during the mid-pregnancy anatomy scan, usually performed between 18 and 21 weeks.
The Relationship Between Placenta Position and Bump Size
The difference in abdominal size or shape due to placental location is considered negligible. The placenta is relatively thin, and its presence at the front does not significantly change the overall outward measurement of the abdomen.
The size and appearance of a pregnancy bump are determined by several factors unrelated to the placenta’s position. A mother’s height and torso length play a role, as a longer torso allows the uterus to grow upward rather than pushing outward, which can make the bump appear smaller. The strength and tone of the abdominal muscles are also influential, with stronger core muscles tending to hold the growing uterus closer to the body.
Other contributors to bump size include the amount of amniotic fluid present and the baby’s position within the uterus. The number of previous pregnancies is also a major factor, as the abdominal muscles and uterus tend to be more relaxed after a first birth, often causing subsequent bumps to show earlier and appear larger. Fundal height, the measurement used by healthcare providers to track uterine growth, is not typically affected by an anterior placenta.
How an Anterior Placenta Affects Fetal Movement
The most noticeable practical difference for the mother with an anterior placenta is the sensation of fetal movement. Because the placenta is positioned on the front wall, it acts like a cushion or shock absorber between the baby and the mother’s abdomen. This cushioning effect can muffle the early, gentler movements, often delaying the experience of feeling “quickening.”
Many women with a posterior placenta feel the first movements around 18 weeks, but those with an anterior placenta may not feel them until after 20 weeks, sometimes as late as 24 weeks, when the baby’s kicks are stronger. The movements felt may also be perceived as weaker or softer in intensity. Kicks and punches might be felt more distinctly on the sides or lower down, where the baby’s limbs are not directly striking the placental tissue.
Even with the insulating layer, it remains important for all pregnant individuals to become familiar with their baby’s pattern of movement. If there is a change, or if movement significantly decreases, it should not be assumed that the anterior placenta is the cause. Any concerns about reduced fetal activity should be reported immediately to a healthcare provider for a proper assessment.