Implantation Calculator: When Did It Happen? (2024)

If you think you may have conceived this cycle, you might be looking for an implantation calculator. These little tools were developed to estimate when the fertilized egg may have burrowed into your uterine lining, thereby beginning your pregnancy. You’ll find a plethora of these nifty little calculators online promising to tell you your implantation date. But the reality is, they can’t.

Before getting into the details on why these calculators aren’t very accurate, here’s how they work. Implantation most often occurs 9 days after ovulation. Based on this information, there are two common ways to estimate when implantation occurs for you.

  1. If you know the date you ovulated, add 9 days.
Ovulation date + 9 days =Implantation date
  1. If you know the first day of your last menstrual period (LMP), add 23* days.
Date of last menstrual period + 23 days =Implantation date

*23 days = 14 (average number of days between LMP and ovulation ) + 9 (average number of days between ovulation and implantation)

Important note: The above calculations are a very oversimplified guess. The reality is that your cycle is variable and the day you ovulate won’t necessarily be consistent from cycle to cycle.

So while using averages like 14 days (between LMP and ovulation) and 9 days (between ovulation and implantation) will tell you when implantation tends to happen on average for women as a whole, it won’t tell you much about when implantation happened for you.

What is implantation?

Implantation is the process of an embryo attaching to the uterine lining. This attachment to the uterine lining is what allows the embryo to receive oxygen and nutrients from the mother, and continue to progress and grow into a fetus.

As soon as implantation is complete, the embryo begins to produce the hormone hCG. This is the hormone that turns a pregnancy test positive.

HCG plays an important role in early pregnancy. When you are not pregnant, a drop in the hormone progesterone is what causes your period to begin (progesterone is the hormone that maintains the uterine lining). But the presence of hCG sends a signal for progesterone production to continue, and your uterine lining is maintained throughout your pregnancy.

What does implantation mean for pregnancy?

When you’re trying to get pregnant, “When did I conceive?” is a pretty common question. However, a better question might be, “When did implantation occur?”

Many people assume that pregnancy begins at conception—the moment that sperm enters the egg.

A more accurate beginning of pregnancy would be the implantation date rather than the conception date. Implantation, or the process of the combined egg and sperm cells attaching to the wall of the uterus, marks the actual start of a viable pregnancy.

According to recent research published in Nature Biotechnology, conception occurs much more readily than implantation, but this does not ensure pregnancy. For the pregnancy to be viable, the cells must make contact with the endometrium and attach to the uterine wall.

As many as two thirds of embryos fail to implant. This indicates that embryos are likely predestined for survival or death before even the first cell division.

If progesterone hasn’t adequately prepared the endometrial lining to support life, or if the blastocyst contains abnormalities, implantation will fail. When this happens, the egg dies and is excreted during your next period.

When does implantation occur?

In most successful pregnancies, implantation occurs 8 – 10 DPO (days after ovulation). The most common day is 9 DPO.

While it’s possible for implantation to occur between 6 – 12 days after ovulation, implantation earlier than 8 days after ovulation is rare.

Can you have late implantation?

According to a study published in the New England Journal of Medicine, the estimated risk of early loss is strongly related to the time of implantation. The study found that early loss was least likely when implantation occurred by the 9th day past ovulation (DPO) and the risk increased with each successive day—most substantially after day 11*.

Here are the specific results:

Implantation Date (in Days Past Ovulation)Risk of early pregnancy loss
9 DPO13%
10 DPO26%
11 DPO53%
after 11 DPO82%

If implantation occurs later, it is more likely to result in early loss or a chemical pregnancy (chemical pregnancy is the term given to a miscarriage that occurs before the fifth week of gestation, and early loss is a miscarriage that happens in the first six weeks of gestation.).

While it’s not fully understood why later implantation tends to result in early pregnancy loss, researchers speculate that embryos that are slow to implant must be impaired in some way.

When did implantation occur for me?

Based on your knowledge of your last menstrual period or ovulation date, you canestimate when implantation might have taken place. (This is why tracking your cycle is incredibly valuable, as it can help you find out when ovulation occurs for your body, specifically.)

If you have a pretty good idea of when ovulation happened, then you can estimate that implantation most likely happened 8 – 10 days past ovulation (DPO).

How long does implantation last?

Most of the time, implantation follows a relatively stable timeline. Sperm can live for about five days, waiting for an egg’s release. Once an egg is released from the ovary, it begins a journey down the fallopian tubes and must be fertilized within 24 hours.

If a sperm does fertilize the egg, and the resulting blastocyst makes it to the uterus, it can still take several days to implant itself in the uterine wall. In all, the entire process usually takes 8 – 10 days, though, in some rare cases, implantation may occur as early as the sixth day, or as late as 12 days, after ovulation.

What are the signs and symptoms of implantation?

Many women wonder when they can start expecting signs and symptoms confirming their hoped-for pregnancy. Who hasn’t Googled “early pregnancy symptoms” 24 hours after sex?

However, implantation symptoms are a debunked myth. Even though many sources use the word “burrowing,” which certainly sounds like it should feel like something, implantation involves only a few cells and causes no unique pain or cramping.

In fact, the cramping people often associate with implantation cramps results from the high levels of progesterone already present during the luteal phase of your menstrual cycle.

If you’re wondering what implantation feels like, remember that the embryo is about half the size of a dust mite—not large enough to cause cramping, pain, or other physical sensations.

How about implantation bleeding? People talk about that all the time, right? Sorry, this one’s a myth, too. One study found that while 9% of women did experience light bleeding or spotting during early pregnancy, it was rarely on the day of implantation.

Essentially, in the very early days of pregnancy, it’s nearly impossible to differentiate between the signs of an impending period and the signs of early pregnancy.

In fact, many of the symptoms often attributed to implantation can be explained by other causes:

  • Bleeding or spotting: spotting during pregnancy an occur for a variety of reasons, and it is often benign. However, there is no evidence that implantation causes bleeding.
  • Cramping: the hormone progesterone is high during the implantation window. Progesterone slows down digestion and can cause bloating, cramping, and general abdominal discomfort.
  • Pain: Many factors unrelated to pregnancy can cause abdominal pain, and when you’re trying to get pregnant, you’re paying closer attention to physical sensations. This can lead to mistakenly attributing the source of pain to implantation.

The only true sign that implantation has occurred is the presence of the hormone hCG in blood or urine, which you can detect with a home pregnancy test.

How long after implantation can I get a positive pregnancy test?

When you’ve got your fingers (and toes) crossed hoping for a positive result, there’s probably one insistent question looping through your mind: How soon can you take a pregnancy test?

Home pregnancy tests are most accurate when taken on or after the first day of your missed period, which usually occurs 12 – 14 days after ovulation.

Pregnancy tests detect the presence of a hormone called human chorionic gonadotropin, or hCG, which is unique to pregnancy. Your body doesn’t even begin producing hCG until implantation is finished—most likely 8 – 10 days after conception. Once it does, the hormone doubles roughly every 48 hours.

Not all pregnancy tests are created equal. Here are some of the best pregnancy tests on the market.

How to help implantation

If you want to increase the chances of getting pregnant, is there anything you can do to promote implantation? The likely answer is no. There is little you can do to prevent a healthy embryo from implanting.

That said, there are a few things you can do to help implantation (or at least things you can avoid so as not to hurt your chances):

  • Avoid taking anti-inflammatories: A study published in the BMJfound an 80% increased risk of early miscarriage with anti-inflammatory use around the time of conception.
  • Avoid hot tubs and saunas: There aren’t any studies investigating the impact of hot tubs and saunas on pregnancy rates. If you want to be on the safe side, you can follow the same advice as pregnant women follow: keep the heat below 103 degrees Fahrenheit) and take breaks every 10 minutes. Warm baths are okay!
  • Consider avoiding intense exercise: A study published in the journal Obstetrics and Gynecology looking at women undergoing IVF found that those who exercised 4 or more hours per week were twice as likely to have implantation failure. Keep in mind that these results may not apply to the general population, and that moderate exercise is good for fertility (and general health!).

What is an implantation dip?

An implantation dip is a decrease in basal body temperature temperature that occurs on a single day during the implantation window (between 6 and 12 days after ovulation). Women who track their cycles using the temperature method will notice that if they become pregnant, temperature will remain elevated. The reason for this is that the hormone progesterone is elevated during pregnancy, and temperature is influenced by progesterone levels.

It’s often said that a brief drop in temperature during the luteal phase is not a sign that your period is coming, but rather caused by the implantation process and therefore a sign of pregnancy.

There are no formal studies investigating implantation dips, but the fertility tracking app Fertility Friend has run an analysis on 117,000 cycles to investigate this phenomenon. The analysis found that the so-called implantation dip is more common in cycles that result in pregnancy: 11% of charts with this pattern did not result in pregnancy, and 23% of charts with this pattern did result in pregnancy.

However, Fertility Friend’s analysis did not produce any evidence that the dip in temperature is caused by implantation. Fertility Friend study found that this type of dip was most likely to occur between 7 and 8 days after ovulation, but implantation most often occurs 9 days after ovulation.

Another explanation for the dip in temperature is that estrogen levels briefly increase during the middle of the luteal phase—often between 7 and 8 days after ovulation (estrogen has a suppressing effect on basal body temperature). It’s possible that cycles resulting in pregnancy are more likely to have stronger luteal phase estrogen surges, which could explain the higher frequency of the implantation dip in conceptive cycles (alternatively, a short luteal phase may carry lower chances for pregnancy).

*Note that studies approximate when implantation occurs based on the first appearance of chorionic gonadotropin in maternal urine.

By Tara Avery |

Tags: chemical pregnancy, early pregnancy, fertility basics, implantation, implantation spotting, trying to conceive

Implantation Calculator: When Did It Happen? (3)

Tara Avery

Tara Avery is a freelance writer and editor currently based out of Vancouver, British Columbia. When she's not traveling the world in search of inspiration, she's writing fiction, film, and non-fiction across a variety of genres.

Implantation Calculator: When Did It Happen? (2024)

FAQs

How do I calculate my implantation date? ›

If you know the date of the first day of your last period
  1. Length of cycle – 14 days = Cycle day number for ovulation. Was this helpful?
  2. Date of ovulation + 9 days = Date of implantation (give or take a few days) Was this helpful?
  3. Date of first day of last period + 23 = Date of implantation (give or take a few days)
Oct 29, 2019

When did my implantation occur? ›

Implantation is the term used to explain when a fertilized egg (sometimes called an embryo) attaches to your uterine lining. On average, implantation happens around six to 10 days after you've ovulated and the egg was fertilized.

How many weeks does it take for implantation to occur? ›

Implantation takes place anywhere between 6 and 12 days after you ovulate. It most commonly occurs 8 to 9 days after conception. So the exact date of implantation can depend on when you ovulated, and whether conception occurred early or late in the ovulation window.

What is the most likely day of implantation? ›

In the majority of successful pregnancies (84 percent), the first hormonal evidence of implantation was detected 8, 9, or 10 days after ovulation; the earliest time was 6 days and the latest 12 days.

How far along am I based on implantation date? ›

Conception date: If you know exactly when your baby was conceived, you can use this date to make a prediction of how far along you are. In the same process as the last menstrual period method, 266 days are counted from the conception date to get an estimated due date.

Can I calculate the day I conceived? ›

Therefore, if you know the first day of period, you can add 11 to 21 days to this day to have an idea of when conception occurred. For example, if you are pregnant and your last period started on March 5, that means you likely conceived between March 16 and 26.

How can I tell if implantation has occurred? ›

Implantation symptoms can include light bleeding, cramping, nausea, bloating, sore breasts, headaches, and mood swings. This article explores the signs that implantation has happened. It also reviews a few false signs of early pregnancy and suggests when to take a pregnancy test.

How early did you feel implantation? ›

Some people may notice symptoms as early as 5 DPO, although they won't know for sure that they are pregnant until much later. Early signs and symptoms include implantation bleeding or cramps, which can occur 5–6 days after the sperm fertilizes the egg.

How soon after implantation can you tell? ›

After implantation, production of hCG starts from cells in the developing placenta (tissue that will feed the fetus). Trace levels of hCG can be detected as early as eight days after ovulation. That means you could get positive results several days before you expect your period to start.

What are signs of failed implantation? ›

Failed Implantation Symptoms

Generally, when implantation occurs, you may experience sensitive breasts and mild abdominal cramping. If you haven't experienced these in the weeks after your embryo transfer, it may be indicative that the implantation has failed. Additionally, you may experience vaginal bleeding.

What are the 4 stages of implantation? ›

As mentioned previously, implantation could be divided into different phases: apposition, adhesion/attachment, invasion/penetration and immune regulation [2,3] (Figure 1). Human implantation is a process that could be divided into apposition, adhesion/attachment and invasion/penetration.

What is the timeline from conception to implantation? ›

Around day 14: Ovulation occurs. Within 24 hours of ovulation: Sperm fertilizes an egg (conception occurs). About six days after fertilization: The fertilized egg implants into your uterine lining. Around day 21: If conception and implantation occurred during this menstrual cycle, you're pregnant.

How to calculate implantation date? ›

Calculating implantation is not an exact science. However, there are a few methods which can be used to estimate the date of implantation. One way is to track ovulation using an ovulation kit or charting basal body temperature. Implantation typically occurs between 6-10 days after ovulation.

How quickly after implantation does hCG rise? ›

How long after implantation does hCG rise? Once the embryo has implanted in the uterus, the hCG hormone starts to rise. It usually takes about 6-12 days for the hCG levels to become detectable in a blood or urine test, which is why we have what's known as the “two-week wait” post-embryo transfer.

Are you pregnant from the day of implantation? ›

within 24 hours of ovulation, the egg is fertilised by sperm if you have had sex in the last few days without using contraception. about 5 to 6 days after ovulation, the fertilised egg burrows into the lining of the womb – this is called implantation. you're now pregnant.

Do you start counting pregnancy from implantation? ›

Your doctor will count the start of your pregnancy from the first day of your last menstrual period. That's about 2 weeks ahead of when conception happens.

How do you know implantation day? ›

Timing. Implantation is a complex process with a brief window — it happens about 6–10 days after ovulation. One factor influencing the timing is that the endometrium changes, thickening and shedding, throughout the menstrual cycle. It is only receptive to a blastocyst for a few days in each cycle.

How do I calculate my due date for IVF implantation? ›

Due date calculation for IVF pregnancies
  1. IVF with own eggs (with or without ICSI) — Egg retrieval date + 266 days (or 38 weeks)
  2. IVF with fresh donor egg cycle (with or without ICSI) — Egg retrieval date + 266 days (or 38 weeks)
  3. Fresh donor embryo cycle — Egg retrieval date + 266 days (or 38 weeks)
Apr 3, 2019

Is conception date the same as implantation date? ›

Around day 14: Ovulation occurs. Within 24 hours of ovulation: Sperm fertilizes an egg (conception occurs). About six days after fertilization: The fertilized egg implants into your uterine lining. Around day 21: If conception and implantation occurred during this menstrual cycle, you're pregnant.

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