Calculating Your Due Date after IVF By Sonja Kristiansen, MD on September 16, 2014

A young woman consulting her doctorWhen it comes to fertility treatments such as in vitro fertilization (IVF), many of the procedures follow an exact science that is tailored specifically to the woman’s or couple’s needs. It may seem ironic, then, then the resulting due date of a pregnancy still cannot be calculated with complete accuracy. In fact, only three percent of births occur exactly on their projected due date naturally. Nevertheless, couples can still gain a general idea of when to expect the birth by taking a few simple factors into consideration. For those currently undergoing IVF treatment in the Houston area, our fertility center offers the following guidance in calculating your child’s due date and probable dates of birth.

Due Date vs. Birth Date

Unless you plan on having an induced labor, it is actually unlikely that the birth will occur precisely on the speculated due date. Even when the prospective day is only a week away, doctors cannot accurately predict when the body will begin to go into labor. For 95 percent of patients, the due date is accompanied by a two week window, both before and after the date, during which the birth may occur. Technically, this means that due dates can have a four week margin of error, although the actual discrepancy is not usually so vast. By keeping this in mind, patients can understand the nature of a due date and why it should only be used as a general estimate and not as a rigid expectation. 

Calculating Your Due Date

Pregnancy is often cited as lasting nine months, but this number can vary between 38 and 42 weeks. For most women, a somewhat accurate due date can be derived by first noting the date of their last period, then subtracting three months and adding one week. This date of the following year is usually used as the due date.

With IVF, however, women can potentially have a more accurate understanding of when the egg was fertilized. For three-day transfers, or embryos that are transferred three days after fertilization, women can pinpoint their due date by subtracting 12 days from the transfer date and then adding nine months. For five-day transfers, subtract 14 days before adding nine months.

Because a woman’s ovulation cycle is careful monitored for IVF and the fertilization process is induced manually, your doctor should be able to give you a very precise due date. Whether this date coincides with the actual birth is not a guarantee, of course, but it at least allows patients to track their pregnancy’s progress within an appropriate context.

Tracking the Progress of Your Pregnancy

Although the primary steps involved with IVF occur prior to and during the embryo’s implantation, there are still many check-ups and tests required throughout the pregnancy. This ensures that progress continues as expected and any problems can be detected as early as possible. From the first few weeks to the birth itself, potential parents can expect the following methods to be used in follow-up exams:

  • Human chorionic gonadotropin test: More commonly known as the hCG test, this is the standard way of determining whether an embryo has successfully implanted in the woman’s womb. One to two weeks after fertilization, an increase in hCG levels can be detected in the women’s blood or urine, as measured by the test.
  • Pelvic examination: Combined with records of the woman’s menstrual cycle, a simple pelvic exam is often an effective way of determining the progress of a pregnancy during the first trimester.
  • Ultrasound: Ultrasound imaging is the most accurate and reliable way of viewing a pregnancy’s progress once eight to 10 weeks have passed. At this point, periodic ultrasound testing will be used to not only track the growth of the fetus but also to determine its health.

Not Sure of Your Due Date?

There may be multiple reasons why a couple could be unsure of their prospective due date. Even with IVF, it can be easy to mix up dates or be unsure of a specific day of conception. Schedule an appointment at our fertility center to speak with one of our professionals, ascertain your due date, and determine the current status of your pregnancy.

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Dr. Sonja Kristiansen

Houston Fertility Center

Dr. Sonja Kristiansen is the founder and Medical Director of Houston Fertility Center. She is a board-certified Reproductive Endocrinologist Infertility (REI) specialist who is proud to help hopeful parents fulfill their dreams of having children. Our center is affiliated with the:

  • American College of Obstetricians and Gynecologists
  • American Society for Reproductive Medicine
  • Texas Medical Association

We provide convenient care for patients from greater Houston and visitors from out of town. For more information about our services, contact our office online or call (713) 225-5375 today.

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