Pregnancy is a beautiful, fun time to dream and plan. Most pregnancies, even with spotting, continue without complication. Although it can be scary, it is important to be positive and hopeful when experiencing spotting, but also cautious. Spotting during the first trimester occurs in approximately 20% of all pregnancies, but does not always mean miscarriage will occur. (1) There are a few reasons why women may spot in the early weeks of pregnancy other than a miscarriage. Some are benign and others are critical. Listed below are some possible causes of first trimester bleeding.
Implantation – Implanting of the fetal sac into the wall of the uterus may cause a little cramping and a small amount of spotting. The bleeding should not continue and the pregnancy is not in danger.
Ectopic Pregnancy – This occurs when the gestational sac implants outside of the uterus. Bleeding may occur because of a fluctuation of the hormones that should remain at a steady state to sustain pregnancy. Ectopic pregnancies are emergency conditions that are threatening to both mother and baby. If lightheadedness and abdominal pain accompany the bleeding, you should contact your provider immediately.
Subchorionic Hemorrhage – This affects approximately 25% of women and may cause bleeding in the first trimester and early second trimester. The subchorionic hemorrhage is identified by ultrasound and is seen between the uterine wall and the chorionic membrane. (2) These are generally benign and resolve on their own. Your provider will order follow-up ultrasounds to follow the progression or resolution of the hemorrhage.
Molar pregnancy – A molar pregnancy is a rare condition in which abnormal tissue grows inside of the uterus instead of fetal tissue. You may have all of the same symptoms of pregnancy but no baby will develop.
Placenta Previa – This is a condition where the placenta covers part, or all, of the cervix. If bleeding occurs with placenta previa, it is indicative of the placenta partially separating from the uterus and can be an emergency situation. With recent technology, placenta previa is usually seen in the routine 20-week ultrasound. Placenta previa can resolve as the uterus enlarges with the growing baby and the placenta will migrate with the uterus, thus resolving any concern. Once found during an ultrasound, further ultrasounds will be ordered to follow the progression or resolution of the previa.
Preterm Labor – Preterm labor is a serious condition, where contractions begin earlier than 37 weeks gestation. With preterm labor, bleeding can occur with cervical change. Contractions may or may not be felt, but it is very important to contact your provider with any rhythmic tightening of the abdomen accompanied with bleeding. Preterm labor can be stopped with medical intervention.
Sexual Intercourse – Bleeding after intercourse can occur due to the friability of the cervix with the increased blood flow to the cervix. The bleeding should be very slight in flow and resolve within hours to a day of intercourse.
It is important to note that no matter what the cause, if you experience first trimester bleeding, you must seek guidance from your provider and have them assess the cause.
- Deutchman, M., Tubay, A.T, Turok, D.K., (2009). First Trimester Bleeding. American Family Physician. Jun 1;79(11):985-992. Retrieved from: https://www.aafp.org/afp/2009/0601/p985.html
- Chhabra, A. (2014). Subchorionic Hemorrhage. Retrieved from: http://emedicine.medscape.com/article/404971-overview
