Pregnancy calculators online - conception and due dates

An online pregnancy calculator can help you determine the due date for your baby's birth, as well as the date of conception. By entering the first day of your last menstrual period (LMP) it will calculate the number of weeks to the birth and your estimated date of delivery (EDD).

The length of pregnancy is accepted as being 40 weeks, or ten lunar months. This translates as nine calendar months or 280 days. Although calculations are based on the first day of your last period, conception normally takes place two weeks later and so pregnancy is actually 38 weeks long, and confusingly two weeks after you've conceived you are described as being four weeks pregnant.

Either way, once you're sure you're pregnant you'll want to know when the bay is due - either use an online pregnancy calculator or work it out yourself. If you have a regular 28-day cycle it is quite easy to calculate when your estimated date of delivery will be. Simply count on nine months and seven days (280 days) from the first day of your LMP. Adjusting the date according to your cycle is easy. For example, if you have a 26-day cycle count on nine months plus five days from your last LMP (278 days). If you have a 32-day cycle, count nine months and 11 days (284 days).

The nine and a half months of pregnancy are divided up into three trimesters. The first trimester covers the first 13 weeks of pregnancy, when the baby's major systems and organs are formed. Most miscarriages occur in the first trimester and it is common to wait to tell friends and family, other than your partner, until after week 12 when the risk has decreased.

The second trimester, from 14 to 27 weeks, usually sees early pregnancy symptoms subsiding. By the end of the second trimester the baby is fully formed and you will begin to show.

During the third trimester, beginning in week 28, your body prepares for the birth and the baby grows substantially. For more information on the different stages of pregnancy see our page on pregnancy week by week .

Despite the fact that health professions agree that pregnancy is 280 days in duration, it's worth remembering that only five percent of babies are born on their estimated date of delivery. Your pregnancy calculator, whether online or using a calendar at home will only give you a rough idea of when you will give birth. Each pregnancy is different and your doctor will offer you the best advice on calculating a due date.

© The Pink Fridge Online Magazine 2008 - Pregnancy Calculator