Pregnancy Due Date Calculator
Estimate Your Due Date & Track Pregnancy Progress
Every pregnancy journey is unique. Select your calculation method below to calculate your estimated delivery date, explore week-by-week development, and review important clinical milestones.
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Pregnancy Dating When You Have PCOS
Women with Polycystic Ovary Syndrome (PCOS) often have longer or variable menstrual cycles. Understanding how this influences pregnancy dating is essential for an accurate care plan:
- Delayed or Variable Ovulation: Standard LMP calculation assumes ovulation takes place on cycle day 14. In PCOS, ovulation may happen on day 21, day 35, or later. This can make an LMP-based calculation overestimate how far along the pregnancy is.
- The Role of Early Ultrasound: An early dating ultrasound (usually between 7 and 12 weeks measuring Crown-Rump Length / CRL) is considered the clinical gold standard. It dates the pregnancy based on actual fetal dimensions rather than cycle days.
- Maintain One Official Due Date: Once your clinician or obstetrician establishes your official due date based on an early ultrasound, that date remains fixed. Avoid repeatedly recalculating or shifting your due date with online tools.
- Specialized Antenatal Oversight: Pregnancy with PCOS benefits from timely early screening, including early glucose tolerance testing (OGTT) and proactive blood pressure monitoring.
Interactive Pregnancy Timeline (Weeks 1 to 40)
Select any week below to explore fetal development, maternal body changes, and standard clinical prenatal care milestones.
Week 1 of Pregnancy
Size: ~MicroscopicFetal Development
Fertilization occurs; sperm meets egg in the fallopian tube to form a single-celled zygote.
Maternal Body Changes
You are not yet technically pregnant by menstrual dating; your uterine lining is preparing.
Care & Milestones
Begin or continue daily folic acid supplementation (400 mcg) to support neural tube development.
Important Pregnancy Milestones & Screenings
Antenatal care follows well-established clinical milestones to ensure maternal and fetal health throughout gestation. Exact timing depends on your doctor's care plan.
Early Confirmation & Dating
Initial pregnancy test confirmation, baseline blood pressure and blood tests, prescription of folic acid, and early viability/dating ultrasound to verify intrauterine implantation.
First-Trimester Screening
Nuchal Translucency (NT) ultrasound combined with maternal serum markers or non-invasive prenatal testing (NIPT) to screen for chromosomal conditions and confirm crown-rump length dating.
Detailed Anatomy Scan
Level-II targeted anomaly ultrasound evaluating fetal organ anatomy, brain and spinal development, heart chambers, limb structures, amniotic fluid volume, and placental location.
Gestational Diabetes Screen
Oral Glucose Tolerance Test (OGTT) to assess maternal insulin response, full blood count (CBC) to screen for gestational anemia, and Rh antibody review for Rh-negative mothers.
Growth & Well-Being Checks
Monitoring fetal growth trajectories, fluid index, and position. Group B Streptococcus (GBS) screening swab is routinely performed between weeks 35 and 37.
Term Care & Birth Planning
Full-term milestone reached. Weekly clinical appointments, monitoring blood pressure, checking fetal presentation, discussing birth preferences, and assessing readiness for labor.
Common Questions About Pregnancy Dating
How is an estimated pregnancy due date calculated?
Traditional pregnancy dating follows Naegele's rule: counting 280 days (40 weeks) from the first day of your last normal menstrual period. This calculation assumes a standard 28-day cycle with ovulation occurring roughly 14 days after menstruation begins.
Why might my ultrasound due date differ from my period date?
If you ovulated earlier or later than day 14 of your cycle—common in irregular cycles and PCOS—your baby's gestational age will differ from the LMP calendar calculation. First-trimester ultrasound measures the crown-rump length (CRL), providing an accurate biological dating that takes precedence.
How accurate is an estimated due date (EDD)?
An estimated due date is a helpful clinical marker, but only about 4% to 5% of babies arrive on that exact day. A full-term pregnancy is defined as delivery between 37 weeks, 0 days and 41 weeks, 6 days.
How does IVF transfer dating work?
Because the exact day and developmental stage of embryo transfer are precisely known, IVF dating is highly accurate: delivery is estimated 266 days from fertilization (Transfer date + 266 minus the embryo age in days, e.g., 261 days for a Day-5 blastocyst).
When should I schedule my first prenatal doctor's appointment?
Most obstetric clinics recommend scheduling your first prenatal consultation between 6 and 8 weeks of pregnancy, or sooner if you have underlying conditions like PCOS, diabetes, thyroid disorders, or a history of recurrent pregnancy loss.
Need Guidance During Your Pregnancy?
From early pregnancy confirmation to antenatal care, personalized medical guidance can help you plan your pregnancy journey with Dr. Shabnam Sharjil.
