Implantation bleeding is bleeding that occurs in women typically when the fertilized egg (embryo) attaches itself to the lining of the uterus. This usually occurs between 6 and 12 days after conception (successful joining of an egg and a sperm). Implantation bleeding may often be mistaken for a regular period because it may look similar and occur around the same time as a woman’s regular period. Hence, women should be able to recognize whether vaginal bleeding is a result of implantation bleeding and know when to seek medical attention. If a woman suspects that her bleeding is a result of implantation bleeding and not a regular period, she should do a home pregnancy test (urine pregnancy test [UPT]) and consult a doctor. Implantation bleeding occurs in around 25 percent of pregnancies.
Facts that distinguish implantation bleeding from menses or miscarriage are as follows.
- Bleeding lasts for a short span
- Blood is brown, black, or pink
- A very little amount of bleeding
- Very mild cramping or no cramping at all
- No clots
Understanding the Menstrual Cycle
During every menstrual cycle, an egg develops and is released from one of the ovaries (ovulation). At the same time, the lining of the uterus becomes thicker due to hormonal changes. If pregnancy does not occur, the thickened lining (endometrium) of the uterus sheds through the vagina accompanied by bleeding. Bleeding usually lasts for three to eight days, and this is known as menstruation or period. The menstrual cycle usually lasts between 24 and 38 days but is typically 28 days long.
Phases of the menstrual cycle:
- Menstruation: It is the period of shedding of the uterine lining accompanied by bleeding. Levels of estrogen and progesterone are low.
- The follicular phase: It is the time between the first day of the period and ovulation. Estrogen levels increase as an egg prepares to be released and the uterine lining builds up.
- Ovulation (Day 14): It is the release of the egg from the ovary. It is the mid-cycle.
- The luteal phase: It is the time between ovulation and the start of menstruation. The body prepares for a possible pregnancy. Progesterone peaks and then drops if pregnancy does not occur, resulting in menstruation or period bleeding.
How Do You Tell if It’s Implantation Bleeding or a Regular Period?
Implantation bleeding is very short-lived, unlike a regular period. It usually only lasts for 24-48 hours, which is the amount of time taken for the fertilized egg to get implanted into the lining of the uterus. Ovulation occurs between Day 14 and 16 and fertilization occurs between Day 18 and 20 of the menstrual cycle. Implantation usually occurs between Day 24 and 26 of the menstrual cycle. Implantation bleeding may occur two to seven days after fertilization. The blood in implantation bleeding is typically dark brown or black, indicating that it’s older blood. Sometimes, it may be red or pink. Blood flow is not heavy, unlike a regular period. Additionally, there may only be some light spotting or a few drops to slightly larger amounts in many cases.
Characteristics of a regular period
- Usually lasts for three to seven days
- Blood in the first two to three days of bright red
- Bleeding is heavy and decreases toward the end of the period
- More painful cramping
- Cramps may begin few days before bleeding and continue for two to three days
Characteristics of implantation bleeding
- Usually only lasts for 24-48 hours
- Bleeding is light and usually brown, pinkish or black, and rarely reddish
- Milder uterine cramping compared with regular periods or no cramping at all
When to Consult a Doctor
If a woman suspects that her bleeding is a result of implantation bleeding and not a regular period, she should do a home pregnancy test (urine pregnancy test [UPT]) and consult a doctor. Implantation bleeding occurs in around 25 percent of pregnancies and is typically not dangerous. However, women should deal with any bleeding during pregnancy with caution. They should consult a doctor for the same if bleeding is very little or there is just spotting. Although not all bleeding is an emergency or a sign of complications, the doctor would advise tests, such as an ultrasound, that are important to evaluate the cause. Bright red blood indicates active bleeding, and it is an emergency, especially if there are blood clots and pain. This could be a sign of something serious such as a miscarriage.
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