2007-06-07 12:13:38 · 6 answers · asked by ஜBECஜ ~Mama to Lucy & bump~ 6 in Pregnancy & Parenting ➔ Pregnancy
Since most women are not certain about the date of conception, doctors calculate your due date from your last menstrual period (based on the 28 "average" cycle).
Calculating from conception IS more accurate, but only if you are absolutely certain which day you conceived. It's tougher than you might think, because even if you had sex only once in your cycle, you may not have actually conceived on that day. Sperm has a long "shelf life."
By the way, babies are actually born 38 weeks after conception and not usually 40.
2007-06-07 12:16:42 · answer #1 · answered by Veritas 7 · 0⤊ 1⤋
Because most women don't really know when the ovulate or possilbly conceive (even if you know when you had sex and ovulated, you don't know when exactly you conceived). In addition, traditional medicine works from "the average" and not from an individual perspective. If you aren't "the average" then the dating system really doesn't work well for you and doctors may suggest induction well before you actually need medical intervention.
If you know when you ovulated, I suggest that you figure out what your first day of your last menstrual period (lmp) would have been in the traditional world and just tell your doctor that date. It will make your due date closer to being accurate.
2007-06-07 19:20:47 · answer #2 · answered by Medical Disaster 3 · 0⤊ 0⤋
Usually people know for sure the first day of their last period....the day of conception is not exactly known. The eggs journey from fertilization in the first 1/3 of the tube closest to the ovary to the uterus could be 3,4,5,6 or 7 days.
2007-06-07 19:16:52 · answer #3 · answered by ~~∞§arah T∞©~~ 6 · 0⤊ 0⤋
Because it is easier to know the exact day you started your period. Conception is a little trickier to figure out, it is just estimated about 15 days after your LMP.
2007-06-07 19:18:44 · answer #4 · answered by Martha R 3 · 0⤊ 0⤋
An actual pregnancy is about 38 weeks. They add in those first 2 weeks before you actually get pregnant in order to have a nice round number that's easier to work with...40 weeks.
Regards,
mari
2007-06-07 19:17:43 · answer #5 · answered by mari m 5 · 0⤊ 1⤋
Because there's no way to know FOR SURE (without an early ultrasound) when you conceived, even if you know the date you ovulated.
2007-06-07 19:16:25 · answer #6 · answered by It's Me 3 · 0⤊ 0⤋