As an expectant mother, you naturally want to know when it is that you’ll get to cradle your baby in your arms for the first time. You might’ve also found that upon learning of your pregnancy, the first thing most people ask you about is your due date!
A due date is an educated estimate of when you’re likely to get into labor and conveys your expected date of delivery. Besides giving an idea of when you’ll be welcoming your baby into the world, your due date also defines a metric for the maternal care that you require during pregnancy.
Discrepancy between due date and date of delivery
Only 1 in 20 women deliver on their estimated due date. Though human gestation period is approximately 9 months (or 280 days), babies rarely keep to an exact timetable. Therefore, a full-term pregnancy is usually classed between 37-42 weeks. Babies born before 37 weeks are considered preterm and those born after 42 weeks are said to be overdue or post-term.
The discrepancy between estimated due date and the actual date of delivery may also result from not knowing the exact dates of ovulation and conception. Conception takes place after ovulation and during the fertile window of a woman’s menstrual cycle, which can vary in length. During this time, awoman can conceive within 5-7 days (lifespan of sperm) after intercourse.
Calculation of due date
Since the date of conception can’t always be properly isolated, medical practitioners typically calculate a due date using the Naegele’s Rule, which is based on the last menstrual period. To calculate your due date, count backward 3 months from the first day of your last menstrual period and add 7 days. The day you arrive at is your estimated due date within the next year.
The method, however, isn’t as precise since it doesn’t take into account the length of your menstrual cycle or the day of conception. Instead, you can use an online due date calculator or a pregnancy calculator to find out when your delivery is due. Besides determining the best time to take a home pregnancy test, by mapping out your menstrual cycle, a pregnancy calculator also predictsthe approximate day ofwhen you conceived. 38 weeks post the day of conception is your due date.
Keeping a check on due date
For a due date that’s as accurate as possible, make an appointment with your doctor. A high-quality ultrasound scan or sonogram during the first trimester can help confirm the gestational age of your baby. If the due dates (calculated as per Naegele’s Rule and the one indicated by the scan) differ by more than a week, the ultrasound is taken as the more accurate measure.
Other clues that assist your doctor in determining your stage of pregnancy and estimated due date include the size of your uterus, fundal height (top of uterus reaches naval at week 20), hearing the first fetal heartbeat (9-12 weeks), and feeling the first fetal movement (16-22 weeks).
It’s interesting to note that the due date thus pinpointed could still be off by a week or so! No one is really sure what triggers labor and only 5% babies are born on their estimated due date.
- Wondering if you’re pregnant? Take a home pregnancy test!
- Get a home pregnancy kit (over-the-counter pregnancy test kit) to take a 5-minute pregnancy test at home.