Group B Strep (GBS) Intrapartum Prophylaxis Threshold

Intrapartum GBS prophylaxis is indicated for: positive rectovaginal GBS culture at 35–37 weeks; GBS bacteriuria this pregnancy; prior infant with GBS disease; unknown GBS status with risk factors (delivery <37 weeks, ROM ≥18 hours, intrapartum fever ≥38°C, intrapartum NAAT positive). Penicillin G 5 million units IV then 2.5–3 million units q4h until delivery.

Weight
Height
Clinical Guidance

BMI is a screening measure of body size, not a direct measure of body fat. The standard WHO categories are underweight (<18.5), normal (18.5–24.9), overweight (25–29.9), and obese (≥30).

BMI can overestimate body fat in athletes with high muscle mass and underestimate it in older adults with low muscle mass. Interpret it alongside waist circumference and clinical context rather than as a standalone diagnosis.

⚕ Clinical Disclaimer: These calculators are for educational and reference purposes only. Always verify results with qualified clinical judgment and current clinical guidelines. Do not use as a sole basis for medical decisions.
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How to Use

Enter the values for the scenario you are assessing. Intrapartum GBS prophylaxis is indicated for: positive rectovaginal GBS culture at 35–37 weeks; GBS bacteriuria this pregnancy; prior infant with GBS disease; unknown GBS status with risk factors (delivery <37 weeks, ROM ≥18 hours, intrapartum fever ≥38°C, intrapartum NAAT positive). Penicillin G 5 million units IV then 2.5–3 million units q4h until delivery. Use the gbs prophylaxis result to inform your calculation.

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