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Obstetrics Data Definitions 

The reVITALize obstetric data definitions are formally endorsed by the following organizations:

  • American Academy of Family Physicians
  • American College of Nurse-Midwives
  • The American College of Obstetricians and Gynecologists/The American Congress of Obstetricians and Gynecologists
  • Association of Women's Health, Obstetric and Neonatal Nurses
  • Society for Maternal–Fetal Medicine

To add your organization to this list, please contact quality@acog.org.

Term Definition Notes

ABRUPTION

Placental separation from the uterus with bleeding (concealed or vaginal) before fetal birth, with or without maternal/fetal compromise
Does not apply if the following occurs:

  • Placenta previa 

ANTENATAL STEROIDS INITIATED 

At least one dose of corticosteroids was administered to accelerate fetal maturation

 

CESAREAN-RELATED DEFINITIONS 

 

CESAREAN BIRTH

Birth of the fetus(es) from the uterus through an abdominal incision
Does not apply if any of the following occur:

  • Abdominal pregnancy
  • Ectopic Pregnancy  

Add separate data item to indicate presence of labor or no labor  

LABOR AFTER CESAREAN

Labor in a woman who has had one or more previous cesarean births. Planned labor after cesarean occurs in a woman intending to achieve a vaginal birth. Unplanned labor after cesarean occurs in a woman intending a repeat cesarean birth.

Should qualify the intended route of birth on admission May result in a vaginal or cesarean birth

PRIMARY CESAREAN BIRTH  

Birth of the fetus(es) from the uterus through an abdominal incision in a woman without a prior cesarean birth 
Does not apply if any of the following occur:

  • Abdominal pregnancy
  • Ectopic Pregnancy  
 

REPEAT CESAREAN BIRTH

Birth of the fetus(es) from the uterus through an abdominal incision in a woman who had a cesarean birth in a previous pregnancy 
Does not apply if any of the following occur:

  • Abdominal pregnancy
  • Ectopic Pregnancy   
 

VAGINAL BIRTH AFTER CESAREAN 

A vaginal birth in a woman with one or more previous cesarean births  

 
     

CLINICAL CHORIOAMNIONITIS 

Usually includes otherwise unexplained fever (at or above 38 degrees C (100.4F)) with one or more of the following:

Uterine tenderness, irritability, or both

  • Leukocytosis
  • Fetal tachycardia
  • Maternal tachycardia
  • Malodorous vaginal discharge 

Nonlaboring, intact membranes with unexplained fever require additional testing. Clinical diagnosis could be supported by laboratory evaluation of amniotic fluid.  

EARLY POSTPARTUM HEMORRHAGE  

Cumulative blood loss of >=1000ml or blood loss accompanied by signs or symptoms of hypovolemia within 24 hours following the birth process (includes intrapartum loss).  

Signs and symptoms of hypovolemia may include tachycardia, hypotension, tachypnea, oliguria, pallor, dizziness, or altered mental status. Cumulative blood loss of 500–999ml alone should trigger increased supervision and potential interventions as clinically indicated. A fall in hematocrit of >10% can be supportive data but generally does not make the diagnosis of postpartum hemorrhage alone. Further research is needed on blood loss for late postpartum hemorrhage.  

ESTIMATED DUE DATE (EDD)

The best EDD is determined by last menstrual period if confirmed by early ultrasound or no ultrasound performed, early ultrasound if no known last menstrual period or the ultrasound is not consistent with last menstrual period, or known date of fertilization (eg, assisted reproductive technology)  

Ultrasound margin of error and “early” to be defined by the College. Pregnancy should not be redated by a later ultrasound after a best obstetrical estimate of EDD has been established. 

FORCEPS ASSISTANCE 

Application of forceps to the fetal head

Should specify whether successful or unsuccessful in achieving birth; this includes both cesarean and vaginal births.  

GESTATIONAL AGE  

Gestational age (written with both weeks and days; eg, 39 weeks and 0 days) is calculated using the best obstetrical EDD based on the following formula: gestational age = (280 - (EDD - Reference Date))/ 7  

Reference Date: date on which you are trying to determine gestational age   

GRAVIDA  

A woman who currently is pregnant or has been in the past, irrespective of the pregnancy outcome

 

GRAVIDITY  

The number of pregnancies, current and past, regardless of the pregnancy outcome  

 

HYPERTENSION-RELATED DEFINITIONS 

 

CHRONIC HYPERTENSION EXISTING PRIOR TO PREGNANCY 

See National Center for Health Statistics definition: elevation of blood pressure above normal for age, gender, and physiological condition. Diagnosis prior to the onset of this pregnancy which does not include gestational hypertension (pregnancy-induced hypertension). 

 

CHRONIC HYPERTENSION DIAGNOSED DURING CURRENT PREGNANCY 

Hypertension diagnosed before the 20th week of current pregnancy.  

 
LABOR-RELATED DEFINITIONS    

AUGMENTATION OF LABOR  

The stimulation of uterine contractions using pharmacologic methods or artificial rupture of membranes to increase their frequency or strength following the onset of spontaneous labor or contractions following spontaneous rupture of membranes.
Does not apply if the following is performed:

  • Induction of Labor 
 

LABOR 

Uterine contractions resulting in cervical change (dilation or effacement)
Phases:
Latent phase: from the onset of labor to the onset of the active phase
Active phase: accelerated cervical dilation typically beginning at 6 cm  

Avoid the term "prodromal labor." Can be spontaneous in onset, spontaneous in onset and subsequently augmented, or induced. 

INDUCTION OF LABOR  

The use of pharmacological or mechanical methods to initiate labor
Examples of methods include but are not limited to artificial rupture of membranes, balloons, oxytocin, prostaglandin, laminaria, or other cervical ripening agents. 
Still applies even if any of the following are performed:

  • Unsuccessful attempts at initiating labor
  • Initiation of labor following spontaneous ruptured membranes without contractions 
 

SPONTANEOUS LABOR AND BIRTH  

Initiation of labor without the use of pharmacological or mechanical interventions, resulting in a nonoperative vaginal birth
Does not apply if any of the following are used or performed:

  • Cervical ripening agents, mechanical dilators, or induction of labor
  • Forceps or vacuum assistance
  • Cesarean birth

Still applies if any of the following are used or performed:

  • Augmentation of labor
  • Episiotomy
  • Regional anesthesia  
 

SPONTANEOUS ONSET OF LABOR

Labor without the use of pharmacological or mechanical interventions to initiate labor
Does not apply if the following is performed:

  • Artificial rupture of membranes before the onset of labor  

May occur at any gestational age.  

TIME OF THE ONSET OF LABOR  

The time when regular uterine contractions began that resulted in labor with or without the use of pharmacological or mechanical interventions

 
     

 MALPRESENTATION 

Any presentation other than a vertex presentation  

Examples: Brow, face, compound, breech, hand, shoulder  

MATERNAL WEIGHT GAIN DURING PREGNANCY 

The last recorded maternal weight prior to birth minus the last recorded weight immediately prior to pregnancy  

Weights used for the calculation should be from the best available information 

NON-CESAREAN UTERINE SURGERY OR SURGICAL SCAR  

Surgery or injury and healing of the myometrium prior to birth other than from cesarean birth  

 

NON-CESAREAN UTERINE SURGERY OR SURGICAL SCAR 

Surgery or injury and healing of the myometrium prior to birth other than from cesarean birth 

 

NULLIPAROUS 

A woman with a parity of zero 

 

NUMBER OF CENTIMETERS DILATED ON ADMISSION 

The last documented cervical dilation in centimeters when the provider orders admission

Cervical dilation may be unknown with:

  • Preterm labor
  • Rupture of membranes
  • Vaginal bleeding
  • Exam refusal by patient (decline)
  • Cervical assessment may be performed by any clinician 

PARITY 

The number of pregnancies reaching 20 weeks and 0 days of gestation or beyond, regardless of the number of fetuses or outcomes 

In cases of multiple pregnancies, parity is only increased with birth of the last fetus  

PERINEAL LACERATIONS

First degree: injury to perineal skin only

Second degree: injury to perineum involving perineal muscles but not involving anal sphincter

Third degree: injury to perineum involving anal sphincter complex
3a: less than 50% of external anal sphincter thickness torn
3b: more than 50% external anal sphincter thickness torn
3c: both external anal sphincter and internal anal sphincter torn

Fourth degree: injury to perineum involving anal sphincter complex (external anal sphincter and internal anal sphincter) and anal epithelium 

 

PHYSIOLOGIC CHILDBIRTH 

Spontaneous labor and birth at term without the use of pharmacologic or mechanical interventions for labor stimulation or pain management throughout labor and birth
Does not apply if any of the following are used or performed:

  • Opiates or nitrous oxide
  • Augmentation of labor
  • Regional anesthesia analgesia except for the purpose of spontaneous laceration repair
  • Artificial rupture of membranes
  • Episiotomy

Still applies if any of the following are used:

  • Uterotonic medications in the third stage of labor
  • Medications that do not stimulate labor or provide pain management (eg, antibiotics, medications to control chronic medical conditions)  
 

PLACENTA ACCRETA

The clinical condition in which any part of the placenta invades and is inseparable from the uterine wall  

Accreta may or may not be supported by pathologic findings. 

PLURALITY  

The number of fetuses birthed live or dead at any time in a single pregnancy regardless of gestational age and regardless of if the fetuses were birthed on different dates
Does not apply if any of the following occur:

  • “Reabsorbed” fetus(es) (those that are not birthed separately from the placenta and membranes)
  • A reduction during the first trimester  
 

POSITIVE GBS RISK STATUS   

Rectal or vaginal culture positive within five weeks prior to birth, or urine GBS culture positive* or GBS bacteruria at any point in current pregnancy, or prior infant with invasive GBS disease 

*As defined by the CDC 

PREGESTATIONAL DIABETES  

Diabetes diagnosed before current pregnancy (coordinate with GDM)

 

RUPTURE OF MEMBRANES-RELATED DEFINITIONS 

 

ARTIFICIAL RUPTURE OF MEMBRANES  

An intervention that perforates the amniotic sac
Applies even if the rupture of membranes occurs during or immediately following a procedure or exam not intended to cause artificial rupture of membranes
Does not apply if rupture of membranes occurs during cesarean birth 

 

DURATION OF RUPTURED MEMBRANES 

Duration from rupture of membranes to birth (in hours and minutes)  

 

PRELABOR RUPTURE OF MEMBRANES  

Spontaneous rupture of membranes that occurs before the onset of labor 

Modified by gestational age categories (eg, preterm, term) 

SPONTANEOUS RUPTURE OF MEMBRANES 

A rupture of the amniotic sac that is not concurrent with or immediately following a digital exam or other transvaginal intervention involving the amniotic membrane
Does not apply if the following is performed:

  • Artificial rupture of membranes 

 May occur at any gestational age

SHOULDER DYSTOCIA  

A birth complication that requires additional maneuvers to relieve impaction of the fetal shoulder  

 

SPONTANEOUS VAGINAL BIRTH 

Birth of the fetus through the vagina without the application of vacuum or forceps or any other instrument

Does not apply if the following occurs:

  • Breech extraction  
 

TERM-RELATED DEFINITIONS 

 

 PRETERM

Less than 37 weeks and 0 days

Late preterm is 34 weeks and 0 days through 36 weeks and 6 days 

 

TERM 

Greater than or equal to 37 weeks and 0 days using best EDD.

It is divided into the following categories:

Early-term: 37 weeks and 0 days through 38 weeks and 6 days
Full-term: 39 weeks and 0 days through 40 weeks and 6 days
Late-term: 41 weeks and 0 days through 41 weeks and 6 days
Post-term: greater than or equal to 42 weeks and 0 days  

 
     

VACUUM ASSISTANCE  

Application of vacuum to the fetal head  

Should specify whether successful or unsuccessful in achieving birth; this includes both cesarean and vaginal births 

VERTEX PRESENTATION

A fetal presentation where the head is presenting first in the pelvic inlet

Does not apply if compound or breech presentation or if brow, face, hand, shoulder, etc. present first in the pelvic inlet  

Should specify whether position is anterior, posterior, or transverse