Your Due Date is calculated by adding 280 days (40 weeks) to the first day of your last menstrual period (assuming a 28-day cycle).
Note that your menstrual period and ovulation are counted as the first two weeks of pregnancy. If you deliver on your due date, your baby is actually only 38 weeks old, not 40.
But delivery is not something that happens on the strike of a clock or even on an exact date. Here are some facts about the concept of Due Date in pregnancy:
1. The first and foremost is for the mother-to-be to wait patiently until the Due date and never go for an induced delivery before the date unless an emergency occurs!!
In the present times, when Labor induction methods are in common practice, experts urge pregnant women never to misuse it and go for it only during an emergency. It is always good to wait till the Due Date.
Studies conducted by the Ohio State University, show that a delivery, even two weeks early can be associated with newborn complications, according to Dr. Celeste Durnwald, one of the researchers.
“There is still ongoing development and maturation of the fetus, even in those last few weeks,” warns Durnwald.
The consequences of being born early include problems such as jaundice, poor feeding, inability to sit in a car seat without breathing difficulties and, rarely, premature lungs. Because of the many recent medical advances, patients and physicians are choosing to push the date of a delivery earlier than ever before, even to 36 weeks gestation, a full month ahead of the mother’s due date - A very Dangerous tendancy.
2. Next to keep in mind is that Due Date is not an exact time as in an Alarm Clock – Length of human pregnancies can vary naturally by as much as five weeks
Normally, you are given a date for the likely delivery of the baby that is calculated as 280 days after the onset of the last menstrual period.
Yet only four percent of women deliver at 280 days and only 70% deliver within 10 days of their estimated due date, even when the date is calculated with the help of ultrasound, according to the Oxford University Press.
Hence Due date should be a good guideline, but never turn out as a strain-causer to the expectant mothers.
“The actual average time from ovulation to birth was 268 days – 38 weeks and two days," said Dr. Anne Marie Jukic, a postdoctoral fellow in the Epidemiology Branch at the National Institutes of Health.
3. Today we have more precise ways to calculate Due Dates for pregnant mothers
Actual delivery in most cases gets put-off by two to three weeks, early or late, from calculated Due Dates. Thus of all the plans that are made around the date, only 5 percent of women get to go by it exactly on their due date.
But now a new meta-analysis suggests that one routine screening test, considering cervix lengths, could help mothers narrow the uncertainty to just seven days from the time of the test.
The researchers found that when the cervix measured more than 30 millimeters at a woman's due date, she had a less than a 50 percent chance of delivering within seven days. However, when the cervix measures 10 mm or less, women had more than an 85 percent chance of delivering within seven days.
Cervical length is a good predictor of labor because it tracks the natural progress of a woman's body toward labor.
4. Call for Labor Induction if Due Date is crossed – a standard treatment culture to set in our society
It has been a common myth around expectant mothers that non-medically required induction of labor leads to a greater likelihood of C-section.
But there are numerous demonstrations that indicate that Labor inductions at full term can actually protect both the mothers and babies – a view supported by obstetricians nowadays.
5. Inducing labor at full term NOT associated with higher C-section rates
According to results published in the American Journal of Obstetrics & Gynecology, the Thomas Jefferson University conducted a new analysis where the results from five randomized controlled trials including 844 women were pooled.
They found no link between induction and rates of C-section in uncomplicated pregnancies of singleton babies at full term.
Instead of an association with C-section, the researchers actually noted a couple of “benefits” of induction at 39 weeks:
Induction was associated with slightly less blood loss than non-induced birth (a volume of about 50ml). Second, meconium staining, a potentially serious complication, was also less likely to occur in babies of induced mothers.
"Some experts in our field are calling for induction at full term to become the standard of care," says Dr. Berghella, Professor of Obstetrics and Gynecology at Thomas Jefferson University.