What is the expected date of delivery (EDD) and prenatal care plan for a pregnancy with a last menstrual period (LMP) of August 12th, 2025?

Expected Date of Delivery and Prenatal Care Plan for LMP August 12th, 2025

Based on a last menstrual period (LMP) of August 12th, 2025, the expected date of delivery (EDD) is May 19th, 2026, calculated by adding 280 days (40 weeks) to the first day of the LMP.

Pregnancy Dating Calculation

• Gestational age should be reported as the number of weeks and days, not rounded weeks, to improve accuracy 1
• Pregnancy dating is calculated using the first day of the LMP and/or an early-dating ultrasound examination 1
• For a LMP of August 12th, 2025:
  • Add 280 days (40 weeks) to calculate EDD
  • EDD = May 19th, 2026

Recommended Prenatal Care Timeline

First Trimester (≤13 weeks 6 days)

• Initial prenatal visit (ideally before 8 weeks):

  • Complete blood count
  • Blood type and Rh status
  • Screening for infections (HIV, hepatitis B, syphilis, chlamydia, gonorrhea)
  • Rubella immunity status
  • Thyroid-stimulating hormone (TSH) levels
  • Urinalysis 1

• Dating ultrasound (7-14 weeks):

  • Most accurate dating with crown-rump length (CRL) measurement
  • Standard deviation of ±7 days 1
  • Important: Ultrasound dating is more accurate than LMP dating and improves both sensitivity and specificity of screening 2

• First trimester screening (11-14 weeks):

  • Nuchal translucency (NT) measurement
  • Pregnancy-associated plasma protein A (PAPP-A)
  • Human chorionic gonadotropin (hCG) or free beta-hCG 1

Second Trimester (14-27 weeks)

• Maternal serum AFP screening (16-18 weeks):

  • Screening for neural tube defects 1

• Anatomy ultrasound (18-22 weeks)

• Glucose screening (24-28 weeks):

  • 50-g oral glucose challenge test (OGCT)
  • Follow-up with 100-g 3-hour oral glucose tolerance test if abnormal 1

• Rh immune globulin (28 weeks):

  • For Rh-negative women 1

Third Trimester (≥28 weeks)

• Group B Streptococcus (GBS) screening (35-37 weeks):
  • Vaginal-rectal culture
  • Positive results require intrapartum antibiotic prophylaxis 1

Important Considerations for Accurate Dating

1. Ultrasound vs. LMP Dating:

   • Ultrasound is superior to LMP in predicting delivery date by at least 1.7 days 3
   • When ultrasound is used instead of LMP, the number of post-term pregnancies decreases from 10.3% to 2.7% 3
   • First trimester ultrasound (ideally between 7-14 weeks) provides the most accurate dating 1

2. Potential Discrepancies:

   • Studies show that up to 33.8% of women have LMP-based EDDs that differ by more than 14 days from the actual delivery date 4
   • LMP dating can result in misclassification of a significantly greater number of preterm and post-term deliveries compared to ultrasound dating 4

3. Optimal Dating Methods:

   • Crown-rump length measurement of 15-60 mm (8-12.5 weeks) has the lowest prediction error of 7.3 days 3
   • After 12.5 weeks, biparietal diameter (BPD) measurements show similar accuracy 3

Prevention and Prophylaxis During Pregnancy

• Aspirin prophylaxis for women at high risk of preterm preeclampsia:

  • Initiate before 16 weeks' gestation
  • Dose: 150 mg nightly until 36 weeks' gestation 1

• Calcium supplementation (1.5-2 g elemental calcium/day):

  • For women with low calcium intake (<800 mg/day) 1

Delivery Planning

• For uncomplicated pregnancies with normal fetal growth:
  • Delivery at 38-39 weeks if estimated fetal weight between 3rd and 10th percentile with normal umbilical artery Doppler 2
  • Delivery at 37 weeks for pregnancies with fetal growth restriction and decreased diastolic flow 2

Remember that this prenatal care plan should be adjusted based on the findings of the initial assessment and any risk factors that may be identified during the pregnancy.