What Are the First Signs & Symptoms of Embryo Implantation?

By (senior clinical embryologist), (embryologist) and (fertility counselor).
Last Update: 10/11/2017

The egg, once fertilized, starts developing and migrates to the uterine cavity to adhere to the endometrium, which means that a new pregnancy begins. Although most pregnant women do not feel symptoms of embryo implantation at this moment yet, it is possible to notice certain changes, as implantation bleeding or discharge, amongst other very early implantation signs that you can find explained below.

Stages of the embryo implantation process

Egg implantation is the process by which the embryo adheres to the endometrium, thereby allowing the fetus to receive by blood doping the oxygen and nutrients it needs from the mother. This way it will be able to continue its development. Implantation begins on the seventh or eighth day after egg fertilization by the sperm, and goes on until about the end of the second week.

For such purpose, a necessary embryo-maternal dialogue occurs through a kind of root-shaped prolongations that extend to the cervical mucus, and are produced by the embryo.

To be able to embed, it is necessary for the embryo to have reached the blastocyst stage, and to be able to break down the blood vessels of the endometrial lining. This will allow the mother's and the embryo's blood to mix and exchange. The fact that the embryo damages these endometrial blood vessels is what causes what is known as implantation bleeding.

To learn more about the steps involved in embryo implantation, we recommend to visit this guide: Embryo implantation: process and stages.

The increase in hormones after implantation generates pregnancy symptoms. Usually they start later, but sometimes they can be noticeable at very early stages. Usually, women start noticing it later, around the 2nd or 3rd week after fertilization. However, some women notice such symptoms previously.

When the embryo invades and penetrates the endometrial lining, the woman can notice a light bleeding or spotting called implantation bleeding.

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When does implantation bleeding occur?

A few days after implantation, some women can have a light vaginal bleeding or spotting, known as implantation bleeding or spotting.

How long implantation bleeding lasts depends on each woman. More often than not, it occurs as a one-time event, which means that it is not a dark red, heavy bleeding, and it often lasts from a few days to 4-5 days or a week. Typically, it comes in the form of just a few drops or a tiny spot.

Implantation bleeding or period?

Implantation spotting or bleeding is expelled through the vagina, and therefore can be confused with menstruation. It usually occurs on day 7 through day 10 after ovulation, concurring with the day at which the period is expected to start. For this reason, it can lead to confusion and uncertainty.

Bleeding because of implantation usually occurs a few days after implantation. Although it may be confused with menstrual bleeding, implantation bleeding is characterized by a more fluid texture than that of menstrual periods. Its color can vary from rosy to brownish.

Also, implantation bleeding can occur as a one-time event, or be present for a few hours through several days, in the form of a light, intermittent spotting. Although it is rather uncommon, it can be prolonged for 5 or even 7 days or more.

Other common signs accompanying implantation bleeding

In addition to the duration of implantation bleeding, its consistency and color, the woman may experience other pregnancy symptoms that can help her to determine whether it is actually implantation bleeding or period flow. One should, however, keep in mind that certain pregnancy symptoms are very similar to PMS symptoms, and for this reason they can be easily confused.

Other symptoms which may be remarkable if they occur when menstruation finishes are:

  • One- to two-day cramping, similar to painful menstrual periods.
  • Slight swelling of the breasts, especially around the areola and the nipple.
  • Digestive disturbances because of diarrhea or constipation; heartburn.
  • Constant urge to urinate.
  • Sleepiness, especially after having eaten.
  • Nausea or even vomiting, especially after waking up, usually from the second week onwards.
  • Abhorrence of food, tobacco and certain smells.
  • First food cravings, a larger number of foods but less nourishing.

Too-frequent observations of any type of sign or change in our organism, together with an unrestrained desire to have a child, can cause you to feel pregnancy symptoms even if you are not pregnant.

In any case, the best you can do is waiting at least 12 days post ovulation (DPO) to take a pregnancy test and to answer your questions.

FAQs from users

What implantation symptoms will I experience after IUI?

By Zaira Salvador B.Sc., M.Sc. (embryologist).

If you undergo IUI (intrauterine insemination) and it is successful, the embryo will adheres to your endometrium as if pregnancy has occurred naturally, that is, by means of intercourse. So, taking this into account, the symptoms and signs you are likely to notice are exactly the same as in any other woman.

What does implantation bleeding look like?

By Zaira Salvador B.Sc., M.Sc. (embryologist).

On a pad or toilet paper, for instance, the color of implantation bleeding can be pinkish red, or even brownish, depending on each woman. Yet, in general, its color is not bright red as in the case of period flow.

Does implantation bleeding have clots?

By Zaira Salvador B.Sc., M.Sc. (embryologist).

Yes. Although it is commonly believed that having a red blood flow with a few clots translates into a miscarriage by default, you should not worry as this is not always true in most of the cases. In fact, typically, nearly half of all pregnant women who have successfully had a healthy child have experienced some bleeding while being pregnant.

Can implantation bleeding occur the day of your expected period?

By Zaira Salvador B.Sc., M.Sc. (embryologist).

Yes. In fact, this is the reason why it is confused with menstruation so often. It can look and even feel like a normal period, and in some cases can be as red as period flow, though rarely. As explained earlier, its color varies from pinkish to brownish, and in some cases is kind of watery/jelly-like and not as abundant as period flow.

Can implantation bleeding affect the results of a pregnancy test?

By Zaira Salvador B.Sc., M.Sc. (embryologist).

Yes, you can take a pregnancy test from day 12 through 15 after ovulation. Experts do recommend to wait until you miss your period, as this way you leave a reasonable period of time for your hCG levels to increase should embryo implantation in uterus have occurred.

Does embryo implantation make you tired?

By Zaira Salvador B.Sc., M.Sc. (embryologist).

Yes. As a matter of fact, fatigue is one of the most common symptoms accompanying implantation bleeding. Implantation can make you feel quite tired all day long because the progesterone hormone increases when a woman is pregnant and acts as a sedative.

Does everyone get symptoms of implantation?

By Zaira Salvador B.Sc., M.Sc. (embryologist).

No, there is no reason why. Some women notice implantation symptoms and some do not. Also, for some might be very obvious, but for others they are basically the same as their common PMS symptoms.

Can you notice symptoms as early as after sperm implantation?

By Zaira Salvador B.Sc., M.Sc. (embryologist).

The term sperm implantation is actually incorrect and we suppose it refers to egg fertilization. What implants is the embryo after the sperm reaches the egg, and they fuse together. After that, the resulting embryo travels through the Fallopian tube toward the uterus. Once there, it will adhere to the endometrial lining, which is what we know as embryo implantation.

You can learn more about this process here: Sperm's journey to the egg.

Suggested for you

We have explained briefly what is involved in the embryo implantation process but if you want to learn the details from fertilization to implantation, do not miss this guide: What is embryo implantation?

Got a positive pregnancy test and feeling implantation symptoms? Congratulations, you are expecting! If you want to learn what are the stages of pregnancy through which you are about to go through in the following nine months, we recommend that you read this post: Stages of pregnancy month by month.

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Authors and contributors

 Silvia Jiménez Bravo
Silvia Jiménez Bravo
B.Sc., Ph.D.
Senior Clinical Embryologist
Bachelor's Degree & PhD in Biology from the Complutense University of Madrid (UCM). Certificate of Clinical Embryologist from ASEBIR (Asociación para el Estudio de la Biología de la Reproducción). Director of embryology laboratory at Reprofiv. More information about Silvia Jiménez Bravo
 Zaira Salvador
Zaira Salvador
B.Sc., M.Sc.
Bachelor's Degree in Biotechnology from the Technical University of Valencia (UPV). Biotechnology Degree from the National University of Ireland en Galway (NUIG) and embryologist specializing in Assisted Reproduction, with a Master's Degree in Biotechnology of Human Reproduction from the University of Valencia (UV) and the Valencian Infertility Institute (IVI) More information about Zaira Salvador
License: 3185-CV
Adapted into english by:
 Sandra Fernández
Sandra Fernández
B.A., M.A.
Fertility Counselor
Bachelor of Arts in Translation and Interpreting (English, Spanish, Catalan, German) from the University of Valencia (UV) and Heriot-Watt University, Riccarton Campus (Edinburgh, UK). Postgraduate Course in Legal Translation from the University of Valencia. Specialist in Medical Translation, with several years of experience in the field of Assisted Reproduction. More information about Sandra Fernández

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