First Trimester : Starting Of Pregnancy Period

First Trimester : Starting Of Pregnancy Period

First Trimester : Starting Of Pregnancy Period Pregnancy is undoubtedly the best part of the woman’s life which every female wants to experience. However, the scientific definition of pregnancy is the period of the fertilization, implantation and then development of one or more offspring in the female’s uterus. In humans the Pregnancy cycle is of approx. 40 weeks from the last menstrual period date.

For convenience the pregnancy of 40 weeks is divided into three trimesters. The first trimester lasts upto 12 weeks. The second trimester is from 13-28 weeks and the third trimester comprises of 29 – till the end of pregnancy i.e child birth.

However in this article we will discuss about the first trimester of pregnancy. This is the most crucial time of the pregnancy as this marks the initiation of the complex developmental phase of a new human being. Also one has to be extra cautious during this trimester as about 60-70% of miscarriages happen during first trimester only.

First Trimester of Pregnancy Period

Changes in the Female Body

Wow! Now that you have confirmed you are pregnant, you have entered in the most complex phase of the fetal development. You may not be looking like pregnant yet but there are lots of things going on in your body as it prepares for this new phase.

These earliest weeks are mainly marked by the earliest symptoms or signs of pregnancy. All these signs are due to fast changing and shifting of the hormone level of estrogen and progestrone. In first trimester you may also experience mild cramping in the lower abdomen due to the stretching of uterus muscles as the baby is getting fixed in the uterine lining. Although there are no noticeable physical changes but there are number of internal changes going on in the body.

About 70% of pregnant women experience morning sickness symptoms which are the integral part of the first trimester, however these symptoms improves after the end of first trimester. By about 6th week you may also start experiencing the pain in breasts which will be tender to touch due to swelling.

First Trimester : Starting Of Pregnancy Period

Although there is long list of possible pregnancy symptoms like food aversions, headaches, mood swings but most important thing to keep in mind is that every pregnancy is different so symptoms also differ, you may not experience any of the above symptoms while a friend of you might experience all of these.

You should also plan your first visit to your gynaecologist during the first trimester to look out for well being of the baby, however, if complications are there they can be tackled on time. Also you will be asked by your doctor to go for routine ultrasound screening between 11-14th week to make sure that things are going well in right direction.

Things to Consider

The most important thing to keep in mind is that this the time when body needs increased nutrients, so start taking balanced diet. Include more of fresh fruits and vegetables in your diet. Also start folic acid supplements as directed by your doctor. Avoid alcohol, smoking and drugs as these may lead to serious birth defects in baby.

Also Read

Pregnancy – Last Trimester
What to Expect During Your Third Trimester
Signs & Symptoms of Ectopic Pregnancy

Fetal Development During First Trimester

As discussed earlier also the first 12 weeks make up the first trimester of the pregnancy. The foetus gets implanted in the 4th week in the uterine lining. Now the Foetus will start developing by getting all the nutrients from here. At this point foetus is at Blastocyst stage and it has started forming placenta. By 5th week the foetus has formed the three layers around it which will eventually form different organs and systems in the foetus as it develops.

First Trimester : Starting Of Pregnancy Period


By the 6th week the foetus starts developing the facial features with the formation of arms and legs. Also the foetus heart starts beating during this period. By 10th month the foetus has formed fully functional four chambered heart and has started looking like a human with the fully formed eyes, earlobes mouth and nose. The baby will now start growing at more rapid pace now.

The foetus is now moving freely in the amniotic sac and getting all the needed nutrients from the amniotic fluid by the help of placenta. By the end of first trimester the foetus will be of size 76 mm and weigh about 28 g as big as a lime. By the end of 12th week the foetus has now developed fingers and toes with the finger nails and toe nails.

The foetus will be able to curl his fingers and toes and can even clench his eye muscles which are visible in ultrasound. You may also be able to listen to your baby heart beat by the end of first trimester. Foetus may also start responding to your touch although you may not feel it.

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