Obstetrics Calculators
Tools for gestational age calculation, due date and prenatal follow-up.
Available Calculators
Explore our collection of specialized calculators
What are Obstetrics Calculators?
Obstetrics calculators are essential clinical tools for obstetricians, general practitioners, and obstetric nurses in prenatal care and delivery assistance. They enable accurate calculation of gestational age, estimation of expected delivery date (EDD), assessment of cervical maturity using Bishop Score, and monitoring of important obstetric parameters. Based on protocols from the Brazilian Federation of Gynecology and Obstetrics Associations (FEBRASGO), international guidelines, and scientific evidence in maternal-fetal medicine, these calculators optimize prenatal care, assist in delivery planning, and contribute to reducing maternal and perinatal morbidity and mortality through adequate monitoring.
When to Use These Tools
- Gestational age calculation at first prenatal visit
- Estimation of expected delivery date for planning
- Cervical maturity assessment with Bishop Score
- Fetal growth and well-being monitoring
- Decision on ideal timing for labor induction
- Clear communication with pregnant woman about pregnancy progression
Clinical Benefits
Frequently Asked Questions
Which method is most accurate for calculating gestational age?
First trimester ultrasound (up to 13 weeks and 6 days) is the most accurate method, with a margin of error of 3-5 days. Last menstrual period (LMP) is used when reliable and cycles are regular. If discrepancy >7 days between ultrasound and LMP, use gestational age by ultrasound.
What is Bishop Score and how to interpret it?
Bishop Score assesses favorable cervical conditions for labor induction: dilation, effacement, consistency, cervical position, and station of presentation. Score ≥8 indicates favorable cervix (high chance of successful induction). <5 is unfavorable, may need cervical ripening before induction.
When is pregnancy considered post-term?
Post-term or prolonged pregnancy is defined as ≥42 complete weeks (294 days) from LMP. Between 41-42 weeks is late term. After 41 weeks, risk of complications increases, with more frequent monitoring recommended and consideration of labor induction after individualized assessment.