IVF Due Date Calculator

IVF Due Date Explained

The average gestation period for a one baby pregnancy is considered to be 40 weeks (280 days) from the last menstrual period. By adjusting the LMP with 2 weeks, the estimated ovulation date is also obtained. This is in the case of a naturally conceived pregnancy.

In the case of an IVF pregnancy, the start dates are planned and scheduled, so known in advance. This offers a more straightforward estimate of the due date. In this case, the start of the pregnancy (adjusted by 2 weeks) is from the day the eggs are harvested or the date of embryo or blastocyst transfer (3-day FET or 5-day FET).

The table below summarizes the number of days that need to be added in the case of each of the IVF options, to retrieve the estimated IVF due date:

For a naturally conceived pregnancy, an estimated due date may subsequently be adjusted or changed following the measurements taken during the dating ultrasound (usually occurring during week 12).

In the case of an IVF pregnancy, if the ultrasound measurements do not match the expected gestational age, clinicians will closely monitor the pregnancy to ensure the fetus is developing as expected.

It is important to note that the actual date of birth cannot be estimated with 100 percent accuracy, not even for IVF pregnancy, where the exact start is known. Due dates are a means to provide with a general window for when the pregnant women may expect to go into labour. A normal pregnancy may last anywhere between 38 and 42 weeks and only 5% of babies are born on their actual due date.

One of the initial factors that may impact on the pregnancy length is the time of implantation. Subsequently, the hormonal profile of the mother and other factors may come into play, shortening or prolonging gestation beyond the 40-week mark.

Pre-term labor is a risk of infertility and IVF conception, the theory being based on the fact that whichever hormonal imbalances caused the infertility, may also impact on the hormones regulating pregnancy and childbirth.

IVF Options

There are several types of egg transmissions that can take place during an IVF cycle:

• IVF with own eggs – when eggs are retrieved from the prospective mother then fertilized in lab;
• IVF with fresh donor eggs cycle – fertilization of donor eggs;
• Fresh donor embryo cycle – retrieval and fertilization of donor eggs;
• 3 days frozen embryo transfer (3-day FET) – the embryo consisting of about 4-8 cells is transferred three days after egg fertilization;
• 5 days frozen embryo transfer (5-day FET) – the blastocyst consisting of about 70-100 cells is transferred five days after egg fertilization.

The embryo transfer date method, especially the 5-day FET more than the 3-day FET has the advantage of assuring a viable fetus.

EDD for Multiple Pregnancy

Multiple pregnancies achieved through the IVF procedure have different typical gestational periods. Whilst in the case of a single baby pregnancy, the gestational age is considered on average 40 weeks, in the case of multiples, gestational ages vary as follows:

• Twins – gestational period 37 weeks;
• Triplets – gestational period 33 weeks;
• Quadruplets – gestational period 31 weeks.

References

Edwards KI, Itzhak P. Estimated Date of Delivery (EDD) [2020]. In: StatPearls Treasure Island (FL).

Jukic AM, Baird DD, Weinberg CR, McConnaughey DR, Wilcox AJ. Length of human pregnancy and contributors to its natural variation. Hum Reprod. 2013; 28(10):2848-55.

Stern JE, Kotelchuck M, Luke B, Declercq E, Cabral H, Diop H. Calculating length of gestation from the Society for Assisted Reproductive Technology Clinic Outcome Reporting System (SART CORS) database versus vital records may alter reported rates of prematurity. Fertil Steril. 2014; 101(5):1315-20.