The first three months, which is the time of organ generation, is the riskiest time.
First trimester
First three months
first
the first trimester
The most vulnerable stage in prenatal development is during the first trimester, particularly between weeks 3 to 8. This is when the major organs and systems are forming and are most susceptible to teratogens, which are substances that can cause birth defects. It is important for pregnant women to take extra precautions during this critical period.
in the first trimester
During prenatal development, a particular organ or body part is most vulnerable to exposure to teratogens during its:
A teratogen is any environmental agent capable of causing a birth defect. It is thought teratogens cause the most serious damage at about 10-14 days after conception. However, any embryotic system is vulnerable, especially during the time it is forming and developing.
The fetal infection rate is above 60% if maternal infection occurs during the third trimester, but the most severe fetal complications occur with first-trimester infection.
Because he or she has already done most of their growing in the second trimester. Also, there is less space in the uterus by the third trimester, so there is less space to grow
In the first trimester when most women miscarry it s because the fetus is not correct developed to make it further.
The first trimester and then it's usually because the embryo/fetus is not viable but damaged by nature somehow.
Any substance that the mother consumes is going to wind up in her blood stream, and it will pass through the placenta to the fetus. The development of the fetus is at its most sensitive during the first trimester, and toxic substances such as alcohol can cause abnormalities.
All organs of the Fetus are formed during first three months of Pregnancy. So drugs taken during this period have high chances of 'Structural' damage to the Fetus. Afterward 'Functional' damage can occur.So your Doctor will be very careful about drugs given in First Trimester ofPregnancy.
Brain development, lung maturation and overall growth are the main changes in the last trimester.