Your Baby's Fetal Station

Position in Relation to the Pelvis During Labor

Station The Pelvis and the Baby
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Station is one of the words you will hear used as your pregnancy delivery date nears. Fetal station is a measurement of how far the baby has descended in the pelvis, measured by the relationship of the fetal head to the ischial spines (sit bones).  The ischial spines are approximately 3 to 4 centimeters inside the vagina and are used as the reference point for the station score.

Fetal Station

Fetal station is stated in negative and positive numbers.

  • -5 station is a floating baby
  • -3 station is when the head is above the pelvis
  • 0 station is when the head is at the bottom of the pelvis, also known as being fully engaged 
  • +3 station is crowning and beginning to emerge from the birth canal
  • +5 station is crowning.

The difference between numbers in the score is equivalent to the length in centimeters. Moving from +1 to +2 is a movement of about 1 centimeter.

Fetal Station During Labor

Station is a measurement of fetal descent in labor and is measured by vaginal exams. Station usually isn't measured until the last few weeks of pregnancy or you may not hear it discussed until you are in labor.

The station number is one of the signs of progression in labor. When labor begins, some women will have a baby who is fairly high in the pelvis with a station of -2. Other women start labor with a baby that is engaged at a 0 station, or lower. In the case of station, lower in the pelvis means a positive number.

You might hear someone say the baby is coming down, which is a positive change in station of your baby. The station of your baby really starts to change once you are pushing.

Fetal Station and Bishop Score

Fetal station is also used as one of the components of the Bishop score, used to predict whether you will need to have labor induced.

The other factors in the score are also determined by the vaginal examination. They include cervical dilation, cervical effacement, cervical consistency, and cervical position. A Bishop score of 8 or more indicates the cervix is ripe you are likely to have spontaneous labor and delivery, while a score of less than 3 indicates you may need to have labor induced.

The modified Bishop score uses station, dilation, length of cervix, consistency, and position instead. As with the original score, a score of 8 or more indicates cervical ripeness.

Fetal Station and Forceps Delivery

Measurement of fetal station is important when a forceps delivery is being considered. The baby must have progressed to an appropriate station for forceps delivery, as defined by the American College of Obstetricians and Gynecologists.

Measuring Fetal Station

The measurement of fetal station by vaginal exam is somewhat subjective and there can be variation between practitioners. The doctor feels for the baby's head and determines where it is relative to the ischial spines. Ultrasound might be used to help determine the fetal station.

Sources:

National Collaborating Centre for Women's and Children's Health (UK). Induction of Labour. London: RCOG Press; 2008 Jul. (NICE Clinical Guidelines, No. 70.) Appendix B, Bishop score.

Takeda S, Takeda J, Koshiishi T, Makino S, Kinoshita K. Fetal station based on the trapezoidal plane and assessment of head descent during instrumental delivery. Hypertension Research in Pregnancy. 2014;2(2):65-71. doi:10.14390/jsshp.2.65.

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