One of the most common questions that expecting mothers ask is this: How far along am I? Whether they are a new mother experiencing their first pregnancy or have already given birth to several children, the question is an important one because of the various health risks or dangers associated with pregnancy during its various stages. Expecting mothers will benefit from knowing how far along they are because it will help project a more accurate delivery date, as well as ensure that they are getting the right medical treatment and care for their bodies during each stage of pregnancy.
There are two different methods or theories which are used to determine the answer to the question “How far along am I?” The first is called the American method and the second is called the Ovulation method. Both of these methods will produce the same delivery date estimate, however depending on which method is used, a woman may be considered more or less farther along in her pregnancy. The American method of determining how far along a woman is in her pregnancy is the one that is typically used by physicians in America, unless they indicate that they are using the ovulation method.
The American method of determining the answer to the question “How far along am I?” can be explained by first giving a (painless!) history lesson.
In the past, very little was known about the inner workings of a woman’s body and about how exactly menstruation, ovulation and conception worked. This was especially true in regards to pregnancy and childbirth. Physicians in the past did know that when the menstrual cycle ceased, pregnancy was the likely reason in fertile women—so they determined that the first day of conception was actually the first day of a woman’s last menstrual period. Thos method was especially popular because most women, especially those of a child bearing age who might wish to be pregnant, kept track of their menstrual periods, while they might not have kept track of other bodily functions related to conception. During the time periods when ovulation wasn’t known or was misunderstood, the tracking of a woman’s menstrual period was virtually the only way that physicians knew how to gauge pregnancy and determine a likely due date for their child.
This theory from the past is now a holdover which is still used today, despite advances in knowledge that have now taught us so much more about how menstruation, ovulation, conception and pregnancy actually work. Under the American method, pregnancy lasts 40 weeks–or, 280 days from the first day of a woman’s last menstrual period. This means that, under the American system, a woman who is “7 weeks along” actually only experienced conception 5 weeks before.
The second system, called the Ovulation System, uses the knowledge that we now possess about menstruation and conception to determine how far along a woman is in her pregnancy. This new system dates a pregnancy as beginning on the day of ovulation in a woman’s cycle – or approximately 2 weeks after her last menstrual period—which, for most women with a normal ovulation cycle, is the day that conception occurs. Under the Ovulation System, a woman’s pregnancy lasts for 38 weeks, or 266 days after the first day of ovulation. This means that someone who is considered “5 weeks along” under the Ovulation System experienced conception 5 weeks before.
The difference between these two systems may seem minor, however, two weeks can make quite a bit of difference to a woman who is pregnant and wants to know when she should be expecting to deliver her child.
Some other differences between these two ‘conception’ systems include the following:
Under the American system, a woman will experience a positive pregnancy test when she is considered 4 weeks into her pregnancy, or approximately 2 weeks after ovulation begins. Under the Ovulation system, a woman will experience a positive pregnancy test when she is considered 2 weeks into her pregnancy, or 2 weeks after ovulation begins. Under the American system, conception does not occur until 2 weeks into the pregnancy, while under the Ovulation system conception occurs during “Week 0,” or immediately when ovulation occurs. These differences can make a difference for women who are using physicians that use one system over the other, so it is important for expectant mothers to ask their physicians which system they use.
It may seem strange that there are two separate systems for determining the answer to a woman’s question of “How far along am I?” but it is simply a matter of there being a holdover from an older medical system in today’s medical practices. If a woman wants to know the approximate time when she conceived her child, she will need to determine which method or theory her physician used when he determine the conception and delivery (or “due”) dates for her pregnancy.