gestational age

 Gestational age is the measure of how far along a pregnancy is, counted from the first day of the last menstrual period (LMP). It is typically measured in weeks and is used to track fetal growth, estimate a due date, and schedule prenatal check-ups. Gestational age is a key metric in prenatal care and helps medical professionals determine if a baby is born prematurely (before 37 weeks) or at full-term.  

Calculation and measurement

From the LMP: Gestational age is commonly calculated from the first day of the last menstrual period (LMP), with the first day being day zero. 

Ultrasound: An ultrasound can also be used to more accurately estimate gestational age, especially in the first trimester. 

In a premature infant: After birth, a premature infant's gestational age is often referred to as their "corrected age" or "post-conceptional age" to track their development until they reach their original due date. 

Importance in pregnancy

Tracks development: It helps doctors and nurses track the baby's growth and development against typical milestones. 

Estimates due date: It is used to estimate the baby's due date, which is approximately 40 weeks from the LMP. 

Guides prenatal care: It helps determine the schedule for important prenatal tests and screenings. 

Pregnancy timeline by gestational age

Pre-term: Less than 37 completed weeks of gestation.

Term: 37 to under 42 completed weeks of gestation.

Post-term: 42 or more completed weeks of gestatio