Understanding Gestation and Pregnancy

What is the term that people often use interchangeably with pregnancy?

What marks the end of gestation?

How is the term trimester typically divided?

What is a more precise way to divide the pregnancy timeline?

What event is often unclearly defined in the context of pregnancy?

From what point do most people count the start of pregnancy?

How many weeks are in a typical pregnancy?

What is the purpose of dividing the pregnancy timeline into weeks?

What is LMP an abbreviation for in medical terms?

At what point is the fertilization of an egg by a sperm said to occur?

What is the term for the period when all organ systems are formed?

What is the milestone reached at around 24 weeks of pregnancy?

What is the term for the period from 37 weeks to 42 weeks of pregnancy?

What can be a complication of being born post-term?

How is the start of pregnancy typically counted?

What is the term for the entire period from fertilization to birth?

Gestation and pregnancy are often used interchangeably, but conception is a cloudy term with no clear definition, so it's best to avoid using it.
Gestation ends at birth, and can be divided into smaller time frames for better understanding.

Pregnancy lasts approximately 9 months, which can be divided into three trimesters: first, second, and third.
A more precise way to divide gestation is by weeks, with 40 weeks being the typical duration.

Conception occurs around the beginning of pregnancy, but counting from the last menstrual period (LMP) provides a more precise starting point, defined as week zero.
Fertilization occurs at week two, when an egg meets a sperm and genetic material is combined.
Embryogenesis lasts about 10 weeks, during which a single cell divides, differentiates, and forms into organ systems.
After embryogenesis, the growth stage is called fetal development, and the individual is considered a fetus.

At around 24 weeks, the fetus has a 50% chance of survival outside the womb.
By the end of the 39th week, the fetus is considered full term, with a range of 37-42 weeks being considered normal.
Births before 37 weeks are considered pre-term, and those after 42 weeks are considered post-term, both carrying potential complications.
The best outcomes occur when birth happens within the normal term range.