Dating pregnancy from conception calculator 100 dating sites in ukrain
However, this only provides a rough estimate of gestation, since a variety of factors -- including fibroids, multiple babies, the amount of amniotic fluid and the baby's position -- can all influence the measurement.
By 28 to 30 weeks of pregnancy, measuring fundal height with tape measure becomes too inaccurate.
Figuring out when you conceived can be tricky, even under the best of circumstances.
But if you discover you are pregnant when you haven't had a recent period -- because you are breastfeeding or have a low body weight, for instance -- or simply can't recall your last period, determining the date of conception becomes even more difficult.
During the second trimester, ultrasound measurements still provide a reasonably accurate measurement of gestational age between 12 and 22 weeks.
By the third trimester, however, ultrasound estimates of gestational age may be off by plus or minus three weeks.
Due dates are always based on a specific start date plus a number of weeks (usually, 38 weeks).
Typically, the start date is the first date of the menstrual cycle, adjusted two weeks out to get the estimated ovulation date.
Abdominal ultrasounds during this time period may underestimate a baby's age by 1.6 days.
If an ultrasound measures your baby as being 8 weeks 6 days, conception occurred approximately 6 weeks 6 days ago.
Simply count back on calendar 6 weeks and 6 days, to find your estimated date of conception.
Fortunately, with some detective work and the help of your healthcare provider, you can still figure out roughly when you conceived your baby.
Check the date you first had a positive home pregnancy test.