How Long Does Implantation Take?

For those looking to become pregnant, the focus is often around the timing of conception, and being sure that the sperm meets the egg. But in order for a fertilized egg to turn into a pregnancy, the second crucial step that needs to happen is implantation. This when the fertilized egg makes itself at home within the uterus.

"After fertilization, the fertilized egg (now called a zygote) travels through the fallopian tube and undergoes several rounds of cell division as it moves towards the uterus," explains Lora Shahine, M.D., F.A.C.O.G., a reproductive endocrinologist and program director of Pacific NW Fertility in Seattle. "Once the zygote reaches the uterus, it will begin to implant itself into the uterine lining, a process known as implantation."

The entire process is, of course, complex, and it's natural to have questions. We turned to some experts to learn more about implantation, including when it occurs, and how long everything takes.

How Long After Conception Does Implantation Occur?

"Implantation typically occurs six to 12 days after conception," explains Alyssa Quimby, M.D., a board certified OB-GYN in Los Angeles and co-founder of Female Health Education. However, this range can vary from person to person, since it's based on how quickly after conception the zygote reaches the uterus.

In addition to the movement of the zygote, there are a number of other factors that need to be in place for successful implantation to occur. These include the proper levels of the hormones estrogen and progesterone, adequate blood flow to the uterus, a healthy embryo, and a receptive endometrium, which is the lining of the uterus onto which the embryo implants.

"And it all needs to be at the right stage of its menstrual cycle," Dr. Shahine points out. Timing is key; if the zygote arrives in fewer than six days, the endometrium may not be ready.

What Are the Signs of Successful Implantation?

There are some physical tells that implantation is occurring. They include the following:

• Light spotting (also known as implantation bleeding)
• Cramping caused by the zygote physically burrowing into the uterine lining
• A slight increase in basal body temperature
• A change in the consistency and amount of cervical mucus
• Breast tenderness, swelling, or sensitivity

It's important to note that successful implantation may also happen without any tangible symptoms at all, says Dr. Shahine. "On the other hand, these particular symptoms can also be caused by other factors like high progesterone levels before a period starts and are not always a reliable indicator of implantation. The only way to confirm implantation and pregnancy is through a pregnancy test."

When Can You Test Positive for Pregnancy After Implantation?

"After implantation, the pregnancy hormone human chorionic gonadotropin (hCG) begins to rise," explains Dr. Quimby. "This hormone is what gives you a positive pregnancy test." Unfortunately for eager and hopeful people, it often takes a bit of time for hCG to reach detectable levels. While it varies from person to person, hCG is generally detectable via a blood test eight to 11 days after fertilization and via a urine test 12 to 14 days after fertilization.

"Therefore, a pregnancy test can typically detect a pregnancy about one to two weeks after implantation, depending on the sensitivity of the test and the timing of the testrelative to ovulation and implantation," adds Dr. Shahine.

Indeed, one of the most common reasons that people see a false negative result on a pregnancy test is because they took the test too early and hCG levels were not high enough to detect. "For the most accurate results," says Dr. Shahine, "it's best to wait until at least a few days after a missed period to take a pregnancy test."

Having Successful Implantation With Fertility Treatments

The menstrual cycle is designed to ready your body for a successful implantation six to 12 days after ovulation, or when conception would occur. For people using a method such as artificial insemination or in vitro fertilization (IVF) to become pregnant, steps are taken to optimize the timing and increase the likelihood of successful fertilization and implantation.

"Depending on the individual circumstances and the advice of a health care provider, an intrauterine insemination (IUI) may be timed to occur just before or just after ovulation, with the goal of placing the sperm in the fallopian tube or uterus when the egg is most likely to be present," says Dr. Shahine. "The health care provider may also monitor the development of follicles in the ovaries via ultrasound to determine the best timing for the IUI procedure."

In an IVF cycle, the timing element that is crucial to a successful pregnancy is when the embryo transfer happens, which is typically on day two or day three (aka a cleavage-stage transfer) or on day five or day six (aka a blastocyst-stage transfer).

Part of making this determination is checking to see if the lining of the uterus is ready for the fertilized egg to implant, notes Dr. Quimby. "This is why cavity evaluation (with ultrasound, a procedure where a camera is put inside the uterus, or a procedure where dye is injected into the uterus) is recommended to ensure there aren't any growths or other abnormalities that could get in the way of successful pregnancy."

If all of these elements are taken into account, you'll be that much closer to a successful implantation and a healthy pregnancy. Of course, if you have further questions about timing your conception, your menstrual cycle, or chances of pregnancy, be sure to reach out to an OB-GYN or health care provider.