When does pregnancy implantation occur? Implantation is a physiological process in which the embryo attaches to the uterus for development. It is the earliest event of pregnancy that usually happens between six to 12 days after ovulation. However, the implantation days may vary slightly depending on when the fertilization occurred after the ovulation, such as in the early fertility window or later.
Some women may experience symptoms such as cramps and bleeding during implantation. However, this may go unnoticed in a few cases. Read on to know the signs and symptoms of implantation and when it usually occurs.
What Is Implantation?
Implantation (of the human embryo) is the attachment of the fertilized egg (the blastocyst) to the lining of the uterus. It is an entirely natural process and an early stage of pregnancy that happens a week after ovulation (1).
Around 15 to 25% of women experience implantation bleeding (2) but is usually mistaken for menstruation as it happens at the same time of your cycle.
When Does Implantation Occur?
In most cases, implantation takes place around nine days after ovulation, but sometimes it may occur as early as seven days or as late as 12 days. So, if ovulation takes place on the 14th day after a period (average 28-day cycle), implantation might occur on the 23rd day.
During ovulation, the ovaries release the eggs. When the sperm enters the fallopian tube, it fertilizes the egg within 12 to 24 hours of ovulation. The fertilized egg, known as a zygote, then travels down the fallopian tube. During this time, the zygote multiplies several times to form a blastocyst, which enters the uterine cavity in five to six days after fertilization.
It then implants to the uterus in a day or two. Therefore, the whole process from fertilization to implantation takes six to ten days. This means that implantation occurs between the 20th and 24th days of your regular menstrual cycle (3).
Possible Signs And Symptoms Of Pregnancy Implantation
Every pregnancy is different, and so are the implantation symptoms. They may also differ from the first pregnancy to the subsequent ones. Some women do not notice any symptoms associated with implantation. Listed below are the possible implantation signs.
1. Implantation bleeding or spotting
It is one of the primary symptoms of implantation and happens when the embryo embeds into the uterine wall (4). Implantation bleeding may be pinkish, scanty, and not as red and heavy as the period bleeding. It is not consistent and does not form clots. The bleeding may be on and off and last from a few hours to two days.
2. Implantation cramping
The second common symptom after spotting is implantation cramping, which is similar to period cramping (5). However, these cramps are milder and are less painful, and may last for a couple of days. You may experience them in your back and lower abdomen. They are sometimes associated with continuous contractions in the uterine wall. If the cramping is severe and longer, making it unbearable, it is advisable to see your doctor.
3. Breast changes
Soon after implantation, your body begins to change. Breasts undergo changes such as tenderness, soreness, and swelling. It is due to the changing female hormone levels after conception (6). In some cases, these changes are visible during ovulation, as well as a week after ovulation.
4. Basal body temperature
The basal body temperature (BBT) is high during implantation and could be a way to determine pregnancy. You may not necessarily track your body temperature unless you are trying to get pregnant. Ideally, you must chart your daily temperature and see if it is increasing. The BBT rises at the time of ovulation due to increasing progesterone hormone and remains elevated when implantation occurs (7).
5. Frequent urination
Within a week of implantation, you may have the frequent urge to urinate. Increased blood supply to the pelvic area might put pressure on your bladder and may increase your urge to urinate (8).
6. Food cravings/aversion
The hormones produced as a result of implantation tend to alter the woman’s likes and dislikes for food. You may crave for foods you have not tasted before or dislike foods you once loved (8).
7. Hot flashes
They are less common signs of implantation and might last for about 15 minutes at the time of implantation. During implantation, the hormone levels rapidly fluctuate, causing hot flashes. Though it is an inconsistent sign, you may consider it in association with the other symptoms.
8. Cervical mucus
An increase in the progesterone levels after implantation might trigger the cervix to swell and increases the blood flow to it. Additionally, the glands enlarge, and the hormones stimulate the glands to produce more cervical mucus. The mucus thus contains some blood, which is why cervical mucus after implantation looks pinkish or brownish in color.
While the above signs could determine your pregnancy, you cannot be sure until you take a test. Moreover, remember that not every woman may see these signs.
What are the stages of implantation?
The embryo implantation occurs on the sixth or seventh day after ovulation. This process has three stages:
- In the first stage, the embryo attaches to the uterine wall (the lining is endometrium). This initial phase of the implantation process is called adplantation. During this stage, the embryo is about five to six days old.
- In the second stage, the fertilized egg penetrates the uterine wall so that it is secure in the uterus. This process is the adhesion of the blastocyst to the endometrium.
- In the third stage, the embryo finally embeds deep inside the uterine wall. At this point, the ovum is located in the endometrial cavity, and as the endometrium grows, the cavity is wrapped better (9).
How To Confirm If Your Implantation Is Successful?
The only way to confirm your pregnancy is through a pregnancy test (serum beta hCG/ urine) (10). If you notice any spotting, i.e., implantation bleeding, wait for about three days and take a home pregnancy test. The later you take the test, the more are the chances of getting an accurate result as your hCG levels increase.
Another way of confirming implantation is going for a sonogram to know if the embryo is attached to the uterine wall.
Experiencing signs, but got a negative test result?
You may be having the signs of successful implantation but may end up with negative test results. This may be because of insufficient hCG hormone. In some cases, it might take up to ten days post-implantation to have enough hCG in the body for a positive pregnancy test result. Therefore, be optimistic and be patient.
Can You Improve Your Chances Of Implantation?
The day of ovulation and the four days before that are the most fertile days in a menstrual cycle. You may track your ovulation days through some signs and symptoms or an ovulation calculator. Having unprotected intercourse during these days can improve your chances of implantation.
Also, you may follow the below tips to have a healthy lifestyle.
1. A balanced diet
- Fiber-rich foods are likely to promote healthy estrogen levels, metabolism, and digestion. You may eat dark leafy greens such as collard, kale or beet greens, ground flax seeds, soaked seeds and nuts, and whole grains. Have about 28 grams of fiber every day (11).
- Superfoods might support healthy hormonal levels. You may include coconut oil, cod liver oil, goji berries (Arctium lappa), and maca (Lepidium meyenii) in your diet.
- Support the healthy growth of uterine lining by taking pregnancy-safe herbs and blood nourishing foods. Herbs such as hibiscus, nettle, red raspberry leaf, and yellow dock infusions or extracts are likely to help. Blood nourishing foods include salmon, grass-fed meats, sunflower and pumpkin seeds, spirulina, and quinoa.
- Include foods that might increase your body temperature. When progesterone levels rise, the body’s temperature also rises. Therefore, a warm womb is an ideal environment to support a new life. Try taking stews and soups with some warming herbs such as cinnamon, ginger, and cayenne.
2. Take enough rest
While waiting for your pregnancy news, you might often observe yourself clenching your jaw, tummy, or holding your shoulder high, which are all signs of stress. Try to avoid the thoughts and activities that are stressful. Have a healthy environment at home and work.
- Go to sleep early and take naps in the day.
- If you are into running or heavy exercises, shift to brisk walking or fertility yoga.
- Nest your womb, which means making it a safe environment for inviting the baby.
- Get a massage, get around with your dear ones, plan for a calm outing.
3. Believe in yourself
You may not get pregnant if you doubt your abilities to give birth to a baby. Change your thought pattern and believe in yourself. Negative thoughts could alter the hormonal balance, thus affecting your chances of healthy ovulation, implantation, and pregnancy.
Positive affirmations, counseling, and meditation could help you to think positive about your body and inner self. However, it is not going to happen overnight. So, be gentle while you shift to a positive approach.
What is Abnormal Implantation?
Abnormal implantation is when the implantation does not occur in the uterine lining or when the placenta does not form correctly. In some cases, implantation could be normal, but the formed embryo might be abnormal (12).
Why Does Abnormal Implantation Occur?
In rare cases, some women could experience abnormal implantation that leads to pregnancy loss. These include:
1. Ectopic pregnancy
When the fertilized egg implants outside the uterus, it is called an ectopic pregnancy. Usually, the implantation occurs in the fallopian tube when the embryo fails to descend to the uterus. In the process, it may, sometimes, attach to the ovary or the abdomen. This type of pregnancy might lead to heavy internal bleeding and tubal rupture (13). Therefore, it needs the immediate attention of experts. There is always a risk of repeat ectopic pregnancy in the future.
2. Hydatidiform mole
This occurs when the rapidly dividing blastocyst implants itself to the uterine wall but does not develop into a full-fledged embryo. Instead of an embryo, the blastocyst turns into a tumor. You may experience all the signs of pregnancy and may even get positive pregnancy test results due to the production of hCG by the tumor cells. You may be able to determine the presence of hydatidiform mole only through an ultrasound (14).
3. Problems with the placenta
Abnormalities related to the placenta are dependent on where the implantation takes place. If the function of the placenta is adversely affected, the pregnancy might not continue. Placental problems could lead to pregnancy loss, and an early loss is called a miscarriage (15). If placental abnormalities occur later in the pregnancy, they might result in pre-term birth, causing complications for the mother and the baby.
Next, we answer a few commonly asked questions about implantation symptoms.
Frequently Asked Questions
1. How long does implantation bleeding last?
Implantation bleeding may last for a few hours to two days. In rare cases, it may continue for more than two days. The length is likely to depend on the amount of blood that is released in the process of embryo implantation.
2. How long does implantation cramping last?
Implantation cramping might last for five minutes. In some cases, the cramps may last for less than five minutes or up to two days.
3. What do implantation cramps feel like?
They feel like a light pricking or pulling pain in the lower abdomen and start about a week before your period is due. Some women may experience only a single episode of it, while some others will have occasional cramping.
Implantation marks the beginning of a pregnancy. Abdominal cramping, spotting, and breast changes are a few signs of pregnancy implantation. Several women experience implantation bleeding, which is often mistaken for period bleeding. If you notice implantation bleeding, conducting a pregnancy test is the most reliable method to confirm conception. Tracking ovulation and having unprotected sex during fertile days increases your chances of fertilization. If you haven’t got a positive result this time, don’t get anxious. You can always try again on your next fertile days.
2. Bleeding During Pregnancy; American College of Obstetricians and Gynecologists (2019)
3. Alok Sharma and Pratap Kumar; Understanding implantation window, a crucial phenomenon; J Hum Reprod Sci. (2012 )
4. Dr. Kalyani Singh; Assessment of First Trimester Vaginal Bleeding Using Ultrasound Sonography; Asian Journal of Biomedical and Pharmaceutical Sciences (2016)
5. Signs and symptoms of pregnancy; NHS (2019)
6. Normal Breast Development and Changes; University of Rochester Medical Center
7. Pregnancy – identifying fertile days; U.S. Department of Health and Human Services National Institutes of Health (2012)
8. Signs and Symptoms of Pregnancy; University of California, Santa Barbara
9. Justin M. Wolter; The Process of Implantation of Embryos in Primates; The Embryo Project at Arizona State University (2018)
10. Pregnancy Test; U.S. Department of Health and Human Services National Institutes of Health
11. Lisa S. Brown; Nutritional Requirements During Pregnancy; Jones and Bartlett Publishers, LLC
12. Eumenia Costa da Cunha Castro; Abnormalities of placenta implantation; Wiley Online Library (2018)
13. Tian Zhu; Ectopic Pregnancy; The Embryo Project at Arizona State University (2010)
14. Hydatidiform mole; U.S. Department of Health and Human Services National Institutes of Health
15. Bleeding in Pregnancy/Placenta Previa/Placental Abruption; The Children’s Hospital of Philadelphia