You cannot have a menstrual period during pregnancy. Once you conceive, you do not ovulate. It means the egg doesn’t get released. Every month your body produces the uterine lining, preparing your uterus for a possible pregnancy. If you do not get pregnant in that month, the lining gets shed as your menstrual period. This does not happen when you are pregnant.
You might have some vaginal bleeding during pregnancy but that is not due to the menstrual cycle. In this MomJunction post, we tell you about the causes of this spotting or bleeding during pregnancy.
There could be several reasons for bleeding during pregnancy.
Causes Of Bleeding In The First Trimester
- Implantation bleeding: It usually occurs two weeks after fertilization when the fertilized egg implants into the uterine lining. Since it occurs around the time of a regular period, women might mistake this spotting for a period. But this is lighter than the period bleeding and lasts fewer days.
- Changes in the cervix: During early pregnancy, the cervix turns soft and rises as more blood reaches the cervix with increasing estrogen levels in the body. Putting any pressure, particularly during intercourse, could cause spotting.
- Other causes of bleeding:
- Ectopic pregnancy (the fertilized egg implants outside the uterus)
- Molar pregnancy (an abnormal form of pregnancy where a non-viable fertilized egg implants into the uterus)
- Cervical infections or inflamed cervix
- Gestational trophoblastic disease (GTD) (abnormal growth of fetal tissue inside the uterus)
- Subchorionic hemorrhage (subchorionic hematoma, where bleeding happens between the placenta and uterine wall)
- Trauma While the bleeding is more likely during the first trimester, it cannot be completely ruled out in the second and third trimesters.
Causes Of Bleeding During The Second And Third Trimesters
Although rare, bleeding can happen during the mid and late pregnancy. The most probable reasons are:
- Sexual intercourse: You might have slight bleeding or spotting (4) after the intercourse as the cervical and vaginal tissues become sensitive.
- Placenta previa: If the placenta implants close to the cervical opening, it could increase the risk of bleeding.
- Placental abruption: The placenta begins to separate from the uterus before the delivery of the baby (second stage of labor), causing bleeding (5).
- Internal examination: Sometimes, your doctor may check the cervical region for any abnormalities, and this procedure could lead to some spotting.
- Labor: Cervical dilation and uterine contractions that help the fetus to move down the birth canal can cause bleeding (6).
- Uterine rupture: If the uterine muscles separate or tear during labor, it could result in excessive vaginal bleeding (7). It is likely to happen in women with a history of C-section or other uterine surgery.
- Vasa previa: Some fetal umbilical cord blood vessels run just above the cervical opening and are at risk of rupturing and bleeding (8).
All the above reasons could cause spotting or bleeding during pregnancy and you might also have symptoms like light cramping, fatigue, and lower back pain, but that is not period bleeding.
It is difficult to say whether bleeding indicates any medical emergency during pregnancy. Therefore, it is important to check with your healthcare provider if you are bleeding.
When Should You See A Doctor?
You should seek medical attention if the following symptoms accompany bleeding:
- Bleeding that is bright red and soaks more than a pad a day
- Severe pain and cramps
- Fainting or dizziness
- Heavy bleeding or passing clots
- Pelvic pain
Bleeding during pregnancy should not be ignored. However, if there is random spotting, you must wait until your next appointment. If it is more than just spotting, you must immediately contact your health care professional. It will help them diagnose the problem if it is addressed well within time to ensure that there are no complications involved in your pregnancy.
- During the first trimester, you may experience bleeding due to implantation or changes in the cervix.
- Molar and ectopic pregnancy or miscarriage may cause bleeding in the first trimester.
- You may experience bleeding during mid- or late pregnancy due to sexual activity, internal inspections, or labor.
- However, if you bleed enough to soak a pad, along with pain, cramps, and dizziness, you may require medical attention.
2. Bleeding in pregnancy/placenta previa/placental abruption; Children’s Hospital of Philadelphia
3. Bleeding during early pregnancy; The University of Chicago Medical Center
4. Vaginal bleeding in late pregnancy; NIH (2018)
5. Pamela Schmidt and Deborah A. Raines; Placental abruption (abruptio placentae); StatPearls Publishing (2019)
6. Complications of pregnancy; University of Rochester Medical Center
7. Antenatal care module: 21. late pregnancy bleeding; The Open University (2019)
8. Vaginal bleeding in pregnancy; NIH (2018)