The creation of life is nothing short of miraculous and is the result of several events occurring simultaneously and under extremely time-sensitive conditions. Fortunately, nature has found a way to make it work. Implantation, the official start of pregnancy, is the perfect example of a critical step dependent on the success of countless other factors.
An egg must first be fertilized and then divide into hundreds of cells while it travels to the uterus. The uterus, in turn, needs to steadily thicken and grow to be ready by the time the fertilized egg arrives.
Upon contact, implantation begins as both fuse together to create the beginnings of an embryo and placenta. This fusion is only physically possible for four days; after that window an egg cannot attach and pregnancy fails.
When all goes according to plan, at the end of a long journey and after many changes, an egg adheres to the uterus and becomes a developing embryo, and then a fetus, and soon a fully-formed baby ready to make a debut into the outside world.
From Fertilization to Implantation
However, for all of this to happen, an egg must first undergo a crucial initial step in the reproductive process: fertilization. For fertilization to begin the egg must encounter a sperm. This sperm will penetrate its exterior and, once this is done, activate a series of crucial changes within it.
Fortunately, sperm can survive within a woman’s reproductive tract longer than most people realize, which increases their odds of success. If, following intercourse, an egg is not available for fertilization, sperm can wait several days until one is.
Timing is crucial; once an egg leaves its ovary, there is a window of just 24 hours in which sperm must meet it, or it will no longer be viable. Upon its release, and as the egg journeys down through the fallopian tube, it is somewhat up to chance whether it does, or does not, come into contact with a sperm.
When a sperm is able to swim through the beginning of a woman’s reproductive system and beyond to find and enter an egg, change occurs instantaneously. Now fertilized, the egg surface alters to become impenetrable to additional sperm. It then begins to divide into more, and more cells, growing bigger and bigger.
This division continues as the egg travels further within its fallopian tube. Five to six days after conception, after the egg reaches the uterus and its final destination, it has now become a blastocyst or a hundred-cell embryo. The next step, which takes place in the uterine tissue, is known as implantation.
What is Implantation?
Implantation is the act of the embryo adhering to the surface of the uterus. This connection to its mother is required not only for it to receive nutrients to grow, but so that it has a system that will eliminate its wastes.
Without successful attachment, pregnancy will not take place. The blastocyst will most likely be carried away with the blood and tissues of a period and removed from the body.
Where Does Implantation Occur?
The uterus has three distinct layers: the perimetrium, the myometrium, and the endometrium. The perimetrium is the external layer, the endometrium is the innermost layer, and the myometrium is the middle layer present in between the other two.
When a fertilized egg enters the uterus it is surrounded on all sides by the surface of the endometrium.
Implantation occurs within this most interior layer of the uterus and is when the fertilized egg, or blastocyst, attaches to its lining. While the blastocyst may adhere within a day, it is possible for it to float around freely within the fluid of the uterus for a few days beforehand.
When Does Implantation Occur?
There is quite a bit of variability as to the exact time that implantation takes place. Implantation generally occurs six to twelve days following a sperm’s encounter with an egg, which is anywhere from one to two weeks after fertilization.
It may happen much sooner in one woman than in another, and even vary between pregnancies of the same individual; as it is often said, every pregnancy is different.
Again, timing is determined by many factors. Among others, the egg may travel more slowly or quickly on route to the uterus. Furthermore, once there, while it could begin implantation immediately it may also delay the process a few days before it starts.
How Long After Ovulation Does Implantation Occur?
On average, implantation occurs around a week after ovulation but can take place anywhere within six to twelve days and usually happens a few days before menstruation would begin.
Menstruation is generally 11 to 14 days following ovulation. This is why when some women bleed or cramp upon implantation they may be confused and instead believe it is normal menses and period pain occurring slightly earlier than usual.
How Long Does Implantation Take?
Implantation is an extremely complex process. Experts continue to study and learn about each step, all which involve a lot of change on a cellular level. The event is likely also influenced by various factors unique to an individual mother.
As a consequence, not only does the length of time it takes for the egg to embed within uterine tissue vary, but so does the length of implantation once it is initiated.
An embryo may float, unattached, for two to three days, or it may bury itself in the uterine lining almost immediately. Full adhesion of a blastocyst may complete in as little as a day or else take four to five days as well.
What are the States of Implantation and Implantation Timeline?
Hormones released during a woman’s natural cycle cause changes in the endometrium, or lining, of the uterus. This begins following a period, as another egg becomes ready to be released from its ovary and produces estrogen. The estrogen acts on the uterine tissue and stimulates its growth.
After estrogen release come an estradiol peak, LH surge, and ultimately ovulation.
Six days after the LH surge (or four to five days following ovulation), progesterone levels increase which cause full development and thickening of the uterine lining. Therefore, it is prepared for a blastocyst just around the time it will have completed its journey through the fallopian tube to enter the uterine cavity.
The period when the uterus is mature and fully ready to receive a blastocyst is limited and termed its “implantation window.” It lasts only four days. Before or after this time the blastocyst will fail to adhere to the uterus and pregnancy will not be possible. This window occurs between day 20 and 24 of a menstrual cycle, or approximately one week following egg fertilization.
It is believed during this time that the uterus begins to absorb uterine fluid to draw the blastocyst nearer and prevent its movement in another direction.
Theories also include a belief that the progesterone and estrogen hormones cause fluid to enter the uterus that pushes the blastocyst to the uterine surface and promotes the implantation process.
1. Apposition Stage
Implantation occurs in three different stages: the apposition, the adhesion, and finally the invasion stage.
During the first, the apposition stage, the blastocyst seeks out an ideal place to implant itself in the endometrium and will “hatch” out of its exterior coating to attach.
When in its receptive window the uterine lining will have developed areas that project outwards and are believed to assist blastocysts in making contact. These growths disappear once the receptive stage ends.
2. Adhesion Stage
Once contact occurs, the adhesion stage begins. Blastocysts interact with the uterus and bind so that they can no longer simply be flushed out of the body. They will remain fixed at this point of contact for the next nine months of gestation.
3. Invasion Stage
The last stage, the invasion stage, is when the blastocyst breaks the membrane or outer lining in the uterus and digs into the blood vessels. Cells from the embryo fuse with cells from the uterine lining. This stage may result in minor maternal blood loss.
What Does Implantation Feel Like?
Implantation is associated with slight discomfort and pain in the lower abdominal region, though these are usually less severe than those typically experienced during menstruation. The sensations have been described as pulling pains or pricking type tweaks.
This may happen only once and then cease, or pain may start and stop, to again return not long afterward.
Signs and Symptoms of Implantation
As many as a third of women experience implantation bleeding as the embryo damages blood vessels within the uterus as it moves around during its attachment.
Because this takes place close to the time of menstruation, and because implantation cramps may accompany it, many women may experience confusion whether what they are feeling indicates the beginning of a pregnancy or the end of another monthly cycle.
Fortunately, although the two cause similar changes, they can be readily distinguished by several key differences.
1. Implantation Versus A Period
Implantation bleeding typically occurs a few days prior to a normal period. This is useful information for women who are familiar with their bodies and have regular cycles that follow a predictable pattern. For those who aren’t as sure of when their period starts or have irregular cycles, this knowledge may be less valuable.
However, there are further differences between the two. For instance, implantation pain is often distinct from normal period cramps. The pulling or pricking pain of an embedding egg is usually less intense than cramping upon menstruation.
The blood itself is also very different; instead of a heavy flow that can be bright red in color, blood caused by a burrowing blastocyst is better described as spotting. The blood is a light pink to a brown color and is so minimal that many women often miss its presence.
It may occur in small drops or smears in underwear or appear only when a woman wipes; if she does not look carefully, she will never see it. In contrast, if a woman can fill up pads of tampons with blood, it is likely a period, not the result of implantation.
Further, if pregnant, the blood generally will not contain clots or large amounts of tissue.
The tiny amount of blood will often be released for mere hours or for, at most, up to three days; if blood is heavy, thick, and lasts for longer, it is more than likely a normal period and not an indication of the beginning of gestation.
There are other symptoms in addition to cramps and bleeding associated with implantation as well; unfortunately, these are also common PMS symptoms. These include nausea, moodiness, headaches, breast sensitivity, and backaches.
2. Other Factors Impacting Symptoms of Implantation
Women who become pregnant for the first time bleed more upon implantation than those who have been pregnant before. Similarly to how women show earlier with each subsequent pregnancy because the uterus and abdominal muscles have been loosened, uterine lining that has already been irritated by a past burrowing blastocyst bleeds less by the activity of future ones.
The above signs of implantation may not apply to women who have changed their routines or started a different type of medication, birth control, or emergency contraceptive.
Periods of high stress may also throw off normal cycles. These may affect the amount of blood, the color, and the texture of a period without pregnancy having taken place. However, in absence of significant changes, the previously described implantation signs are considered reliable indicators.
How to Confirm If Your Implantation Is Successful?
As many as two-thirds of fertile cycles end without implantation and pregnancy. The reasons for this are many-fold.
The uterus may not be prepared to support a fertilized egg because estradiol and progesterone hormones were not present in sufficient amounts which prevent the full development of the uterus. The embryo may not be viable due to chromosomal abnormalities, or else it may fail to properly adhere to the endometrium for any of several reasons.
Because of this, it is not the fertilization of the egg but implantation that signals the beginning of a pregnancy.
Even if a blastocyst makes it to the uterus, without connecting to the endometrium, it is possible for it to flush out before the attachment is possible. In this case, it will exit the body mixed with the blood of a monthly cycle.
Women often wonder about the earliest indications that can help them know whether or not theirs was one of the one-third of successful baby-making cycles. Very early hints do exist.
Women who track their vital signs routinely during cycles, for example, will notice that right before or following their period their temperature and pulse rate will usually drop. For this reason, women who have a higher temperature and resting pulse than normal can have hope that this may indicate that implantation has been successful and pregnancy has officially begun.
After implantation, once hCG levels have risen to an appropriate level, pregnancy tests will come back positive, confirming beyond a doubt that pregnancy and successful implantation have taken place.
Failed Implantation Symptoms
When implantation does not occur, estrogen and progesterone levels within the body drop. This causes arteries within the uterus to constrict and the layer of tissue that would otherwise nourish a growing baby is shed from the uterus and expelled from the body.
Additional indicators of falling progesterone include lower internal temperature and a slower resting pulse. This may happen the day a period starts, or the next.
How to Increase Your Chances of Implantation?
Both the quality of the egg and the sperm that combine upon the first step in the reproductive process strongly influence the chances of successful implantation. Fertilized eggs with chromosomal issues, for example, often fail to successfully implant.
Men and women should take care to live the healthiest life possible to ensure the release of good-quality eggs and sperm that will have optimal chances of developing into a thriving embryo.
1. A Woman’s Health
Women attempting to conceive should not engage in overly physical activities. Create a well-balanced exercise routine of a correct intensity so that it does not leave the body drained or excessively sore.
Working out has many benefits and helps improve blood circulation everywhere, including to the uterus. Routines that include yoga or walking with plenty of stretching both before and after are especially helpful.
An inclusive and varied diet will provide the body with all the nourishment it needs to be in top condition. This will promote the health of eggs as well as of the uterus and other bodily organs. Eating foods that improve circulation and body warmth such as ginger, onion, and fish may also prove beneficial.
Similarly, avoiding various behaviors known to harm the body facilitates implantation success. Do not smoke or drink more than the recommended amounts. Try to minimize exposure to both acute and chronic stress as well. All of these negatively impact blood circulation, in addition to several other systems.
Stress may also place pressure on the fallopian tubes which may compromise the ability of sperm to reach an egg.
Overall maternal health significantly affects the chances of becoming pregnant as well; a visit to a doctor can help identify the presence of diabetes, various autoimmune conditions, indicators of celiac disease, etc. which could reduce fertility.
Though, in the absence of any risk factors, this testing may be considered unnecessary. For most, routine annual exams are sufficient. And, when a condition is identified, proper treatment may help improve the chances of pregnancy success.
Women with verified conditions such as endometriosis, fibroids, or polycystic ovary syndrome may also find that it impacts their ability to get pregnant. They may require medical intervention as well for a successful pregnancy.
2. A Man’s Health
As for a potential father, sperm quality can affect the odds of successful implantation as well. Men who have undescended testes, who contracted mumps, took enhancing synthetic hormones, or used various medications both in the past or more recently may find that any of these has reduced the quality of their sperm.
A general practitioner can complete an analysis to help identify or rule out sperm-related issues. Sperm need to be healthy and intact; of the tens of millions if not over one hundred million sperm that enter a woman’s body during intercourse, often only a few hundred will make it anywhere near an egg.
There are many barriers to sperm success that are present naturally in the female reproductive tract. Additional factors negatively impacting sperm mobility could easily prevent pregnancy.
Men trying to conceive should take measures to maintain optimal health as well, such as regular exercise and a balanced diet. Avoid things such as trans fats which reduce fertility in women and lower sperm count in men.
While women are encouraged to remain warm, men must keep their testicles cool, as heat can also damage sperm.
With both men and women taking measures to be in the best health possible, chances will increase that they will have a viable blastocyst that can successfully implant and grow.
What Happens After Implantation?
Following the implantation of a blastocyst, its cells develop into the embryo and placenta.
The placenta will become crucial as it delivers oxygen and various nutrients to a developing baby and helps with the elimination of wastes from the baby’s system. The umbilical cord connects a baby to the placenta, and the placenta, in turn, is fastened to the uterus.
After implantation, the cells that develop into the placenta begin to make hCG, which acts on ovaries so that they stop releasing eggs. Additional eggs are unnecessary, as pregnancy has already been achieved.
Just a few weeks after implantation the embryos begin to form critical systems needed by a baby upon birth; they develop the beginnings of a circulatory system, as well as a heartbeat.
By eight weeks, the embryo is now considered a fetus. At this stage, the fetus will be bigger than a half-inch and well on the way to further development.
As the fetus grows, so do the levels of hCG within a pregnant woman’s body. While hCG can be identified with a blood test 11 days following conception, it takes a few days longer (generally 12-14) to pick it up in urine.
Levels of the hormone double every two to three days for the first 8-11 weeks. At the end of this time levels reach their highest. Then, for the remainder of the pregnancy levels will decline and then level off.
While hCG is necessary for pregnancy, low levels do not necessarily mean problems will occur. Many women have healthy babies despite a lower measured amount of the hormone. When an ultrasound indicates a baby is developing normally, this should alleviate most concern.
HcG Levels After Implantation
HCG is not present in any significant amount within the body until after implantation, which stimulates the body to start its production. Also known as the pregnancy hormone, hCG is what home and blood pregnancy tests use to verify a successful pregnancy has been achieved.
It does not register on tests immediately; it may take several days for the hCG levels to increase to high enough levels to be detected by even the most sensitive tests.
HCG that measures less than 5IU/ml does not indicate pregnancy; levels must have increased to 25 mIU/mL for a positive reading. Measurements between these amounts may require retesting.
On average, experts recommend that women wait three to four days following implantation bleeding or around the time of a missed period before testing to see if they are pregnant.
On average, hCG levels three weeks after the last menstrual period (one week before the next) can vary from 5 to 50 mIU/mL, so many women will not measure high enough for an accurate reading. The week after that has average ranges from 5 to 426 mIU/mL, so many will still fall below the 25 mIU/mL necessary for pregnancy confirmation.
Even the fifth week after the last period (a week after a missed one) has a range that begins at 18 mIU/mL and ends at 7,340 mIU/mL. It is not until six weeks after the last menstrual period, and two weeks after the next period should have occurred, that the lowest number in the average range of hCG levels is well above the 25 mIU/mL minimum at 1,080 mIU/mL.
It is for this reason that waiting is beneficial for most women, however eager they may be to test. Negatives at the earliest stages of pregnancy are not reliable as levels may just be too low for measurement.
Low hCG Levels
When women register at lower than expected hCG levels while pregnant, this may be for several reasons. Among these is the simple explanation that the pregnancy is not as far along as it was believed to be.
Unfortunately, there is a chance also that a miscarriage has occurred or that a woman has a blighted ovum. Another possibility is that the pregnancy is ectopic.
Signs of Fertilization Before Implantation
There are several potential changes that may occur between egg fertilization and implantation of the blastocyst within the uterus. These are also experienced by some women only later on after implantation or when not pregnant at all but right before a period. As each woman is a unique individual, some variability should be expected.
One of the potential changes a woman may experience between fertilization and implantation are alterations in the sensation and appearance of the breasts. These may be feelings of tenderness, enlargement, or the darkening of the areolas.
Exhaustion may be another indicator of conception and is generally attributed to hormones. Further, the hormonal changes that take place following ovulation also often result in bloat. Bloat is standard around the time of a period, but some women find that they are more bloated than otherwise during the earliest stages in their pregnancies.
However, as the signs of fertilization before implantation can be experienced at other times and even in the absence of fertilization, waiting for more reliable symptoms before getting hopes up is recommended.
Can You Take a Pregnancy Test During Implantation Bleeding?
While women can take a pregnancy test during implantation bleeding, recommendations are to wait at least three days after it has completely stopped for overall accuracy. Otherwise, it will likely only provide a false negative even when a woman is pregnant.
If a couple is impatient and tests earlier than recommendations indicate, they should test again at least two to three days later if results are negative. Levels of hCG should have doubled within this time frame.
It is understandable that many prospective parents are eager and excited to find out if they are expecting, but waiting is truly the best bet. The most accurate pregnancy tests can be expensive, not to mention the whirlwind of emotions that a couple may experience if results are negative and it is unknown whether or not the reading is valid.
During implantation bleeding or before missing a period will be too soon under most circumstances for accurate results. There are many reasons to remain patient.
How Soon After Implantation Can You Take a Pregnancy Test?
The best results will be seen a week after spotting occurs. Many pregnancies may not register on a home pregnancy test until the day of a missed period or as many as 19 days after ovulation.
It is also wise to accept a negative result after a certain amount of time has passed. Testing done weeks after a period has been missed, and that indicates a negative result, is a pretty strong guarantee that pregnancy has not occurred.
Do not lose hope if things have not been successful the first, second, or even third time of actively attempting to become pregnant. Odds are 20% that women between 25 and 35 who have unprotected intercourse on a regular basis will experience success. Approximately half of women under 37 will become pregnant within three months, and almost all within 18.
It is not until after 18 months of trying that medical assistance may be necessary. Until that point, stay optimistic and watchful for the signs that implantation has taken place.
Watch for Bleeding After Implantation
Sometimes women experience spotting or bleeding later on following a missed period. The odds are that, due to the timing of the blood, this is not implantation bleeding.
If pregnant, bleeding following implantation may occur for various reasons. Many of these are not severe, such as cervical irritation, which may take place following routine examination by an OBGYN.
Intercourse may result in irritation as well, or in tiny tears that can also cause bleeding. Exercise that is highly strenuous can aggravate a woman’s body as well. Finally, infection is another possibility.
For bleeding during pregnancy after implantation, a doctor’s expertise is recommended. The important thing is not to panic; half if not more of women who bleed during their pregnancies go on to give birth to a healthy newborn.
However, when bleeding persists, becomes heavy, or when it occurs later on during pregnancy, it may be more cause for concern.
Possibilities of serious issues include things such as a molar pregnancy or a miscarriage. When blood is accompanied by vomiting, dizziness, or pain on one side, an ectopic pregnancy may be indicated.
Implantation and Pregnancy
Following the fertilization of an egg and its journey to the uterus, it will then implant within the endometrium layer of uterine tissue to begin the official start of a pregnancy. It remains where it has attached for the nine months of gestation; becoming a fetus and secreting hCG hormone as it grows.
This hormone will eventually be picked up on a test to confirm that a woman has successfully conceived, although testing before a missed period will likely deliver a false negative, even if pregnant.
Wait until the recommend time to test, and until then, be mindful of any signs of implantation that may indicate pregnancy a good time before a test can.