Am J Obstet Gynecol 1998; 178:678. On average only 5% of births take place exactly on the estimated due date. Due date of pregnancy calculator week by week if your cycle is irregular, this method may not work for you at all. Clinical management guidelines for obstetrician-gynecologists. These 20 beautifully illustrated cards help you record and remember those special moments in the first few months with your seek. This is the method used by "pregnancy wheels". Your baby is swallowing more now and producing meconium. And keep in mind that if your baby is born on your due date, he or she is actually only 38 weeks old, not 40, since you clock in two weeks of pregnancy before you actually conceive. With your baby now weighing a little over 4 pounds, you might be waddling — and having trouble getting comfy in bed. While all the information contained here is well-reseached and accurate, it shouldn't be used to self-diagnose problems or pregnancy concerns. The average cycle length is 28 days,
