What does negative 1 mean when you are 90 percent effaced and 4 centimeters?

== == "Negative 1" refers to the position of the baby's head in relation to your cervix. Negative numbers imply that the baby's head is still floating above the cervix. Zero position means the baby's head is engaged. Positive numbers means the baby's head has begun its descent through the cervix and into the birth canal. The higher the negative numbers, the higher up in your uterus the baby is located (ex., - 3 is higher up than - 2). The higher the positive numbers, the lower into the birth canal the baby is located (ex., +3 is lower -- closer to birth -- than +1).