Many expectant mothers who are getting pregnant for the first time are not very familiar with the calculation methods for in vitro pregnancy, expected delivery time, and last menstrual cycle. During the process of conceiving a baby, it is very important to understand the growth and development of the baby. Therefore, today we will introduce the calculation methods for the gestational age and expected delivery period of IVF, so that expectant mothers can have a detailed and thorough understanding.

If it is natural conception, how is the gestational age calculated?

Normally, doctors calculate assisted reproduction during pregnancy based on the last menstrual period of expectant mothers. That is to say, the calculation method for gestational weeks is the total number of days from the first day of the last menstrual cycle to the calculation date. After converting the total number of days into weeks, the number of gestational weeks is calculated.

For example, if the last menstrual period is September 1, 2021, and today's assisted reproductive date is September 27, 2021, then the distance between the last menstrual period and now is 26 days, 26 divided by 7 equals 3, and the remainder is 5. Therefore, the correct gestational age is 3 weeks and 5 days. But if the mother's menstrual cycle is relatively long or irregular, then it is necessary to determine the specific gestational age through ultrasound examination at this time.

How is the gestational age calculated after successful IVF transplantation?

Usually, in the case of natural cycles and with fertilization on the 14th day, there are slight differences in the method of calculating gestational age in IVF. First, it depends on the day of successful embryo transfer. For example, if an embryo is transferred on day D3, the actual time is the third day after fertilization; If the blastocyst is transferred for D5 days, it is the fifth day after fertilization, so an additional 3 or 5 days are required from the day of transfer.

For example, if D3 embryos were transferred on October 1st (fresh embryo transfer and frozen embryo transfer are the same), then October 1st is 2 weeks+3 days; So the same D5 day blastocyst is 2 weeks+5 days.

How to calculate the expected delivery time after successful in vitro transplantation?

After successful transplantation, the expected delivery date for IVF is calculated as follows: subtract 3 or add 9 from the month of the last menstrual cycle, and add 7 to the date of the last menstrual cycle.

For example, if the last menstrual period is October 20, 2020, then the expected delivery date is July 27, 2021. If the last menstrual period is December 3, 2020, then the expected delivery date is September 10, 2021.

How to calculate the last menstrual cycle of IVF patients?

1. If the embryo is transferred on the third day, the date of the last menstrual cycle is the transfer date minus 17 days. For example, if the transplant date is April 20th, then her last menstrual period will start on April 3rd.

2. If the blastocyst is transplanted on the 5th or 6th day, the date of the last menstrual cycle is the date of transplantation minus 19 days. For example, if the transplant date is April 20th, then the last menstrual period is April 1st.