Calculating your due date can be tricky. Unfortunately, it's not as simple as knowing the date of your last menstrual period (LMP), a tool used by most online due date calculators and care providers. Even the high-tech ultrasound, which can be helpful in detecting some things, is not the best at figuring out your due date.
Knowing your most accurate due date is important as you near the time of birth. Many care providers impose limits for how long a woman can go past 40 weeks before scheduling an induction (despite guidelines from the American Congress of Obstetricians and Gynecologists stating that a full-term pregnancy is 42 weeks). If your due date is calculated for July 1, but your actual due date is July 10, you may receive unwarranted pressure to induce when in reality, your baby has not even reached 40 weeks gestation. Inductions carry a host of risks and interventions and should be scheduled only if medically necessary for the health of you and your baby.
So how do you calculate your most accurate due date? Childbirth Connection has created a simple worksheet to answer questions and use in conjunction with your care provider to determine your due date. The form is below, and it can also be downloaded on the Childbirth Connection website.