To know exactly how many weeks of pregnancy you are and how many months it means you need to calculate the gestational age and for this you only need to know the Last Menstruation Date and count in a calendar how many weeks there are until the current date so you know everything. You can find the due date calculator on the web to help you as well.

What if I do not know the date of last menstruation?

When the woman is not sure what the last menstrual day was, adding information to the pregnancy calculator, the safest way to know how many weeks of gestation is and what the probable date of delivery is through ultrasound or uterine height, which is what the doctor usually calculates the weeks and months of pregnancy. For this are considered:

  • Amount of Beta HCG in blood;
  • Uterine height after the 12th week of gestation and
  • Ultrasonography requested by the gynecologist.
  • How to Know Gestational Age in Weeks and Months
  • How to calculate gestational age in weeks

Understanding your periods

To calculate gestational age in weeks without pregnancy calculator, note the date of the last menstruation on a calendar. Every 7 days, as of this date, the baby will have another week of life.

The calculation is made so because although the woman is not yet pregnant, it is very difficult to define exactly when fertilization occurred, because sperm can survive up to 7 days in the woman’s body before fertilizing the egg and actually initiate the pregnancy.

How to know gestational age in months

  • 1st Trimester 1 month until 4 weeks and a half of gestation
  • 1st Quarter 2 months 4 and a half weeks to 9 weeks
  • 1st Trimester 3 months 10 to 13 weeks and a half of gestation
  • 2nd Trimester 4 months 13 and a half weeks of gestation at 18 weeks
  • 2nd Trimester 5 months 19 to 22 weeks and a half of gestation
  • 2nd Trimester 6 months 23 to 27 weeks of gestation
  • 3rd Trimester 7 months 28 to 31 weeks and a half of gestation
  • 3rd trimester 8 months 32 to 36 weeks of gestation
  • 3rd trimester 9 months 37 to 42 weeks of gestation

Usually the pregnancy lasts 40 weeks, but the baby can be born between 39 and 41 weeks without problems. However, if labor does not start spontaneously until the age of 41 weeks, the doctor may choose to induce labor with oxytocin in the vein.

How to calculate the probable date of the baby’s birth

To calculate the probable date of delivery, which should be around 40 weeks after the , it is necessary to add 7 days to the DUM, then count 3 months back and then put the following year. You can also look for due date calculator on the web.

This calculation does not give the exact date of the baby’s birth because the baby can be born between 37 and 42 weeks of gestation, however, the mother is already informed of the likely time of the baby’s birth.