What Does Days Post-Transfer (DPT) Mean?
Days post-transfer (DPT) refers to the number of days that have passed since the embryo transfer portion of an in vitro
fertilization (IVF) procedure. There are several significant milestones that occur after an
embryo has been transferred to a uterus that are measured in days-post-transfer (DPT) including, implantation,
embryo development, and testing for pregnancy.
FertilitySmarts Explains Days Post-Transfer (DPT)
During IVF, embryos are generally transferred either 3 or 5 days post-retrieval, or during the next menstrual cycle using frozen embryos. Here are some significant DPT milestones for a 5 day embryo transfer. (For a day 3 transfer, add 2 days to each number.)
- 1 DPT - The embryo hatches from its outer shell, the zona pellucida.
- 2 DPT - The embryo attaches itself to a spot on the uterine lining.
- 3 DPT - Implantation starts, as the blastocyst starts to embed into the lining of the uterus – may cause light bleeding.
- 4 DPT - The blastocyst embeds itself deeper into uterus lining and invades the blood vessels in order to nourish itself.
- 5 DPT - Implantation is regarded as complete, and the embryo now has cells developing into the placenta and cells developing into fetal tissues.
- 6 DPT - The growing embryo causes the release of the hormone human chorionic gonadotropin (hCG) into the mother’s bloodstream.
- 7 DPT - More hCG is released.
- 8 DPT - More hCG is released and the placenta start functioning.
- 9 DPT - At this point, hCG levels are usually high enough to be detected by a home pregnancy urine test, although a home test is not the more reliable test for pregnancy.
- 10 - 12 DPT - Patients typically undergo two blood tests for the beta subunit (BSU) of the hCG hormone. These tests are far more reliable than a urine test, and two are done to confirm that hCG levels are elevated and still rising.
- 14 DPT - The embryo’s yolk sac may be visible on an ultrasound, confirming a clinical pregnancy.