Changes that occur in pregnant women both physically and psychologically will vary according to gestational age. Therefore, it is important for pregnant women to determine the gestational age to respond to changes experienced by the body during pregnancy. Pregnancy age can also help you to determine the health of the growth and development of the fetus.

There are many ways you can do to find out the gestational age. Either manual or medical. Even from methods that have low to high accurate values. Here are some ways that can determine gestational age.

### The Importance of Knowing Your Gestational Age

Gestational age can be distinguished by week, month or trimester. Obstetricians or midwives often use the week to determine gestational age, this is considered more accurate in predicting birth estimates.

Gestational age is the time of pregnancy which is calculated from the first day of the last menstrual period and is generally expressed in weeks or days. By knowing the gestational age, pregnant women can prepare themselves for delivery.

For obstetricians or midwives, gestational age can help to carry out screening tests as well as important examinations during pregnancy, even in knowing and assessing fetal maturity and labor induction when experiencing birth months.

Thus, it is very important to know the gestational age. In the development of increasingly sophisticated technology, gestational age can be determined by using a pregnancy calculator. Some of the old methods that are still used in calculating gestational age will be described in this article.

## How to determine gestational age

Method of First Menstruation Last Menstruation (HPHT)

Determining the very traditional gestational age is by using an estimate of the first and last menstrual period a woman experiences menstruation. This calculation method assumes that the occurrence of conception is calculated on the 14th day of the menstrual cycle.

This method is very easy to do even for those of you at home. The only drawback of this method is that ovulation varies greatly, from cycle to cycle or from individual to individual. Calculating gestational age using this method tends to result in an older gestational age. plus minus mistakes for 2 weeks.

The ways you can do to determine gestational age using HPHT are as follows:

If your HPHT starts April 25 2015 while today is May 25 2015, then in other words, your current gestational age is 4 weeks. Quite easy right? You only need to remember the first day of your period and the last day of your period.

Next is the estimated day of delivery known as the Naegele formula, which is calculated using a 28 day cycle. Before doing this rumis, first know the first day of the last menstruation.

Naegele’s formula for knowing the day of delivery is the day of the first period +7, while for the month -3 and for the year +1. Meanwhile, for months that cannot be reduced by 3, the month will be added by 9 and no additional years will be made. Whereas for women who have menstrual cycles other than 28 days, the formula is the first day and last day of menstruation plus 9 months. As for the estimation, the difference in the length of the menstrual cycle is reduced by 21 days. Examples like this: HPHT + 9 months + (menstrual cycle length-21 days).

## Method of Calculating the Height of the Uterus (Fundus Uteri)

How to find out the uterine height can also be done by calculating the height of the uterus, only you have to use a medical expert, obstetrician or midwife. As for how to calculate the uterine fundus where the examination is done by feeling the palpation you are looking for is the uterine fundus while calculating a high gestational age compared to standard benchmarks .

At 12 weeks gestation, the height is 1/3 above the simpisis. Meanwhile, at 16 weeks gestation, the height is right in the center of the symphysis. Approaching 20 weeks of gestation, the height is 2/3 above simpisis. Even when your pregnancy is predicted to have entered the age of 24 weeks the position is as high as the center.

Furthermore, at the age of 28 weeks of pregnancy, you experience 1/3 above the center. Meanwhile, for gestational age 34 weeks, it is in the center of the xiphoid process. Even at 36 weeks of gestation, it is now high to experience xiphoid process. Whereas before delivery, which is 40 weeks of gestation, it can be measured with 2 fingers under the xiphoid process.

Generally, using this method can use a measuring tape. The measuring tape used uses a zero point that is placed on the symphysis pubis and then drawn and across the midline of the stomach until it reaches the top. The results can be read using the cm scale and compared using the standard used.

Calculating Gestational Age with Ultrasound

Ultrasound was introduced in the early 70s. Now the ultrasound examination is an examination to determine an accurate gestational age. In addition, using this method can detect and detect multiple pregnancies, abnormal development that occurs in babies and also identify placenta previa.

As for knowing the gestational age using ultrasound is done in 3 ways, namely measuring the diameter of the pregnancy sac in young pregnant women who are estimated at 6-12 weeks of gestation. Then measure the head and buttocks of the fetus estimated at 7-14 weeks of age compared with reference standards. While the latter is to measure the diameter of the fetal head at 12 weeks of gestation.

## Determining Gestational Age Based on Fetal Movement

Fetal movement which is used to calculate gestational age is very easy to do, when the pregnant woman feels the first movement. Generally, the first movement felt by pregnant women at 19-21 weeks of gestation in women who are first pregnant. Whereas in women who are pregnant both and thereafter are felt at 17-19 weeks of gestation.

This method does have many weaknesses, especially for pregnant women who are not aware of fetal movements. The movement of the fetus between pregnant women and other pregnant women has differences so that it is not a benchmark that has a large accurate value in determining gestational age.

Thus, to determine more accurate results and comparisons of the results of HPHT and USG, you can do a crocscheck. If based on the HPHT calculation, you have labor on the 1st and according to the USG on the 4th, you can differentiate it for more than 10 days, for example by 14 days from estimates can even also use ultrasound results that become a benchmark.

To minimize the risk, it is done by using a diary to find out the development and position of the fetus according to gestational age. Carry out an examination at a pregnancy doctor or midwife and also understand the signs of labor given by the doctor at 36 weeks of gestation.