Why not include more obscure scores (HELLP, ISSHP criteria, etc.)?

We're starting with the highest-traffic, most universally-applicable bedside references. If there's a score you reach for daily that we don't have, send a request — we'd rather build six tools clinicians actually use than thirty no one does.

Are these references safe for patient use?

Patients can read them, but they're written for clinical context. We've placed warnings on tools where patient self-application could cause harm — for example, the Bishop score isn't useful unless someone has actually performed a cervical exam, and the Apgar score is assigned by the delivery team, not by the parent. The fundal height, AFI, and FHR references are reasonable for patient education when paired with their provider's interpretation.

What's a good Bishop score for induction?

A Bishop score of ≥8 is considered favorable for spontaneous-style induction with high likelihood of vaginal delivery. Scores of 6-7 are intermediate. Scores ≤5 are unfavorable and typically benefit from cervical ripening (mechanical dilation, prostaglandins) before pitocin. The original Bishop validation was in multiparous patients; ACOG notes the score performs less well in nulliparas.

What does an Apgar of 7 mean?

Apgar 7-10 is reassuring. 4-6 is moderately depressed and prompts active resuscitation efforts. 0-3 is severely depressed. The score is meant to direct resuscitation decisions in real time, not to predict long-term outcome — a single low Apgar does not predict cerebral palsy or neurological injury (per ACOG Committee Opinion 644).

When is fundal height unreliable?

Fundal height (in cm = gestational age in weeks ± 2-3 cm) is most reliable between 20 and 36 weeks. It loses accuracy with maternal obesity (BMI >30), uterine fibroids, multiple gestation, polyhydramnios/oligohydramnios, fetal malposition, and after engagement (head descended into pelvis near term). When in doubt, ultrasound.

What AFI is considered oligohydramnios?

AFI 24 cm is polyhydramnios. The single deepest pocket (SDP) <2 cm is an alternative diagnostic threshold for oligohydramnios that some institutions prefer over AFI.

What FHR is considered tachycardia or bradycardia?

Baseline >160 bpm sustained ≥10 minutes is fetal tachycardia. Baseline <110 bpm sustained ≥10 minutes is fetal bradycardia. Both warrant evaluation — but baseline alone doesn't classify tracing. NICHD three-tier categorization integrates variability, accelerations, decelerations, and contractions.

Who needs GBS prophylaxis in labor?

Per CDC 2010 guidelines: positive 35-37 week vaginal/rectal culture; GBS bacteriuria in current pregnancy; previous infant with invasive GBS disease; or unknown status with risk factors (preterm <37 wks, ROM ≥18 hrs, intrapartum fever ≥100.4°F). Penicillin G is first-line; cefazolin for non-anaphylactic penicillin allergy; clindamycin or vancomycin for anaphylactic allergy depending on susceptibility.

Medically reviewed by Samantha L. Fox, RN, BSN, MSN

Nursing Informaticist · United States Navy Nurse Corps · Last reviewed April 30, 2026

⚕️ Clinical References

Clinical Reference Tools

Bedside references for OB and ED clinicians: Bishop score, Apgar, fundal height, amniotic fluid index, fetal heart rate, and GBS prophylaxis dosing. Built and clinically reviewed.

For clinicians and clinically-curious parents.

Not a substitute for clinical judgment. Each tool represents one input into a decision — never the decision itself. Original references and current ACOG guidance are cited inline.

Bishop Score Calculator

Predicts the likelihood of successful induction of labor. Score 0–13.

dilation

effacement

station

consistency

position

Total Bishop Score

0 / 13

Unfavorable cervix — cervical ripening recommended

A Bishop score below 6 (especially below 4) is associated with a higher rate of failed induction and cesarean delivery. Cervical ripening with prostaglandins, mechanical dilation (Foley balloon, dilapan), or both is typically used before oxytocin induction.

Reference: Bishop EH. Pelvic scoring for elective induction. Obstet Gynecol. 1964;24:266-268. The original 5-component score remains the most commonly used predictor of induction success.

Amniotic Fluid Index (AFI) Reference

Phelan four-quadrant AFI measurement, in centimeters. Normal third-trimester range: 8–18 cm.

AFI (cm)

AFI	Interpretation
< 5	Oligohydramnios
5–8	Borderline low
8–18	Normal
18–25	Borderline high
> 25	Polyhydramnios

GBS Intrapartum Antibiotic Prophylaxis

Dosing reference for intrapartum antibiotic prophylaxis against neonatal Group B Streptococcus disease.

Per CDC/ACOG: indicated for GBS-positive screen, GBS bacteriuria in current pregnancy, prior infant with GBS disease, or unknown GBS status with risk factors (preterm, ROM ≥18h, intrapartum fever).

Recommended (no allergy)

Penicillin G

Dose: 5 million units IV load, then 2.5–3 million units IV

Frequency: every 4 hours until delivery

First-line per CDC/ACOG. Most narrow-spectrum option.

Alternative (no allergy)

Ampicillin

Dose: 2 g IV load, then 1 g IV

Frequency: every 4 hours until delivery

Penicillin allergy — low risk of anaphylaxis

Cefazolin

Dose: 2 g IV load, then 1 g IV

Frequency: every 8 hours until delivery

For non-severe penicillin allergy (rash without anaphylaxis, angioedema, respiratory distress, or urticaria).

Penicillin allergy — high risk of anaphylaxis, GBS susceptible to clindamycin

Clindamycin

Dose: 900 mg IV

Frequency: every 8 hours until delivery

Only if antibiotic susceptibility testing confirms susceptibility (resistance is increasing). If unknown susceptibility, use vancomycin.

Penicillin allergy — high risk OR clindamycin-resistant

Vancomycin

Dose: 20 mg/kg IV (max 2 g per dose)

Frequency: every 8 hours until delivery

Updated 2020 CDC weight-based dosing. Older guidance was a flat 1 g — current recommendation is weight-based.

Adequate prophylaxis

Adequate intrapartum prophylaxis is defined as ≥4 hours of penicillin, ampicillin, or cefazolin before delivery. Clindamycin and vancomycin do not meet the “adequate prophylaxis” threshold for changing newborn management — newborn workup decisions follow the standard CDC algorithm regardless of duration when those agents are used.

References: CDC. Prevention of Perinatal Group B Streptococcal Disease — Revised Guidelines, MMWR 2010; ACOG Committee Opinion 797: Prevention of Group B Streptococcal Early-Onset Disease in Newborns, 2020 (vancomycin weight-based dosing update).

References

Bishop EH. Pelvic scoring for elective induction. Obstet Gynecol. 1964;24:266-268.
Apgar V. A proposal for a new method of evaluation of the newborn infant. Curr Res Anesth Analg. 1953;32(4):260-267.
Phelan JP et al. Amniotic fluid index measurements during pregnancy. J Reprod Med. 1987;32(8):601-604.
ACOG Practice Bulletin No. 229 — Antepartum Fetal Surveillance, 2021.
Macones GA, Hankins GD, Spong CY, et al. The 2008 NICHD Workshop Report on Electronic Fetal Monitoring. Obstet Gynecol. 2008;112(3):661-666.
CDC. Prevention of Perinatal Group B Streptococcal Disease — Revised Guidelines, MMWR 2010 (and ACOG Committee Opinion 797, 2020).

Frequently Asked Questions

Clinicians, nursing students, residents, and clinically-curious patients. The math and lookup tables here are the same ones used at the bedside in OB triage, L&D, and the ED. We've cited the original references and current ACOG guidelines so you can verify any value.

No. Every score and reference value here represents one input into a clinical decision — not the decision itself. Bishop scores don't account for parity or clinical gestalt. Apgar doesn't replace continuous newborn assessment. FHR baseline is one part of a three-tier categorization that requires variability, accelerations, and decelerations. Use these as quick references, not as automation for clinical judgment.