Dr. Randell's Pregnancy Event Calculator   Have you tried adding, subtracting, multiplying, and counting on your fingers, and you're still not sure when your baby is due? Use Dr. Randell's handy tool to figure out the approximate date. (Remember, fewer than 5 percent of women give birth on their actual due date) You can also use this calculator to determine the milestones during your pregnancy. Dr. Randell uses the number of weeks since your last menstrual period to describe how far along you are in your pregnancy.   Enter first day of your last menstrual period: January February March April May June July August September October November December 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 Enter length of your cycle (in days): 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 Weeks of Pregnancy Estimated Date Event 2 Weeks (0 dpo) Ovulation/Fertilization Date 4 Weeks (14 dpo) Home Pregnancy tests often positive 6-7 Weeks Fetus and fetal heart usually visible on transvaginal sonogram 9 Weeks Major fetal organs have all formed 11-13 Weeks U/S screen for Down syndrome (nuchal thickening) if indicated 13 Weeks 2 Days First Trimester ends 15-20 Weeks MSAFP testing suggested 18-20 Weeks Optimal time to do anatomical sonogram 20-22 Weeks Fetus should be moving by now (Quickening) 23-24 Weeks Fetal viability begins 26 Weeks 4 days Second Trimester ends 26-28 Weeks Glucose Challenge Test (GCT) for diabetes If Rh-Negative receive RhoGam 28 Weeks Over 90% neonatal survival 32 Weeks Consider sonogram to check fetal growth 37 Weeks Term of pregnancy begins GBS testing between 35-37 weeks 40 Weeks (266 dpo) DUE DATE 41 Weeks Consider Fetal Evaluation 42 Weeks Postdate begins