Can You Be Pregnant and Still Get a Period?
Medically reviewed by Rachel Liberto, RN on February 20, 2020
- It is not possible to get your period while you’re pregnant.
- Early pregnancy symptoms can feel like normal PMS symptoms because both are caused by the same hormone: progesterone.
- Women who experience spotting or light bleeding during pregnancy are no more likely to miscarry than women with no bleeding.
It’s not hard to find online stories about women who still got their periods while they were pregnant, but is there any science to back up those claims? A missed period is supposed to be one of the first and most clear-cut signs of pregnancy. Unfortunately, our bodies don’t always like to play by the rules. Two common examples of this are:
- Many women experience period-like bleeding and PMS symptoms, even after getting a positive pregnancy test.
- Some women experience period-like bleeding, assume that they’re not pregnant, and then start experiencing unexpected symptoms of pregnancy.
Can You Really Get Your Period While Pregnant?
The short answer is no. Your period, by definition, only occurs after you ovulate, and you cannot ovulate when you are pregnant.
During the first half of your cycle, your uterine lining thickens in preparation for a possible pregnancy. After ovulation, your progesterone levels increase, maintaining your uterine lining.
If you don’t get pregnant, progesterone levels drop after about two weeks, and your lining begins to shed—this is your period.
If the egg has been fertilized, and if it successfully implants in your uterine lining, then it will start secreting the hormone hCG, or human chorionic gonadotropin. This hormone signals to your body to keep your uterine lining intact. You may still experience some form of bleeding or spotting, but, by definition, it is not your period.
How Common Is Period-Like Bleeding in Early Pregnancy?
This epidemiological study looked at the pregnancies of 4,539 women and found that 27% of women without miscarriage reported experiencing some form of bleeding during pregnancy. The most common time for bleeding to occur was 5 – 8 weeks of gestation (or 1 – 3 weeks after a missed period).
Of those women:
- About 15% experienced bleeding at the same time as their next expected period.
- Only 2% experienced a heavy flow that lasted 3 or more days and could be mistaken for a regular period.
- No women experienced bleeding episodes that followed their regular monthly cycle, including typical period length and heaviness.
How Much Bleeding Is Normal in Early Pregnancy?
When talking about pregnancy discharge, there is no true “normal.” Pregnancy symptoms are different for everybody. However, light spotting tends to be more common than bleeding that is heavy enough to be mistaken for a period. The above study, published in Annals of Epidemiology, found that, of the women who experienced bleeding during early pregnancy:
- 76% only had episodes of spotting (which the study defined as blood only noticed when wiping)
- 18% experienced light bleeding (where the heaviest day of bleeding was still lighter than a woman’s typical menstrual flow)
- 6% experienced bleeding as heavy or heavier than their normal flow
To sum it up, 27% of women experienced some form of bleeding during early pregnancy. Of those women, about 6% experienced bleeding that was heavy enough to be mistaken for period bleeding.
Does spotting or bleeding in pregnancy mean miscarriage?
Any amount of bleeding during pregnancy can be scary, but it’s not necessarily a sign of miscarriage. Women who experience spotting or light bleeding during pregnancy are no more likely to miscarry than women with no bleeding, according to a 2010 study published in Obstetrics & Gynecology.
Heavy bleeding, on the other hand, was strongly predictive of miscarriage. Women in the study who experienced heavy bleeding had three times the miscarriage risk of women with no bleeding. (Heavy bleeding was defined as bleeding that was as heavy or heavier than a woman’s usual menstrual period.)
Aside from the risk of miscarriage, vaginal bleeding during the first trimester may be associated with an increased risk for preterm birth, and low birth weight.
Can Implantation Bleeding Look Similar to Period Bleeding?
Implantation bleeding is one of the most commonly cited explanations for early pregnancy bleeding. But surprisingly, there is no evidence that the process of implantation causes bleeding.
In fact, there is evidence that implantation does not cause bleeding. This study found that, for most women who experience spotting during early pregnancy, it doesn’t start until at least five days after implantation. Yes, bleeding during early pregnancy is fairly common, but it has nothing to do with when the fertilized egg implants in the uterine lining.
What Causes Bleeding During Early Pregnancy?
Occasionally, there is a clear cause for spotting or bleeding during early pregnancy:
- Cervical irritation
- Infection (such as bacterial vaginosis)
- Subchorionic hematoma
- Ectopic pregnancy
- Miscarriage or chemical pregnancy
But much of the time, no clear cause can be found for episodes of bleeding or spotting during pregnancy.
It has been theorized that early pregnancy bleeding may have something to do with the formation of the placenta. In the first few weeks of pregnancy, the corpus luteum is responsible for producing the progesterone necessary to maintain the pregnancy. But progesterone production shifts to the placenta around week 7.
The authors of the study in Obstetrics & Gynecology note that this coincides with when bleeding is most commonly observed, during gestational weeks 5 – 8. They surmise that heavy bleeding during this time may signal a problem with development of the placenta.
When Should You Call Your Healthcare Provider About First-Trimester Bleeding?
Unfortunately, there really isn’t any surefire way to tell whether your early-pregnancy bleeding — whether it’s just light spotting or heavier bleeding with clots — is harmless or a sign of a more concerning issue.
Though vaginal bleeding during pregnancy can indicate an underlying medical condition, it doesn’t mean that you should fear the worst. Yes, bleeding during pregnancy could be a miscarriage symptom, but it could also be caused by any of the above factors. The only way to diagnose the cause of the bleeding is to go to your healthcare provider for further testing.
If your bleeding is accompanied by dizziness or pain on only one side of your body, it may be a symptom of an ectopic pregnancy, a serious medical condition. If you notice those symptoms, you should call your physician immediately.
If you are concerned about any bleeding during your pregnancy, even if you aren’t experiencing any additional symptoms, don’t hesitate to contact your doctor to discuss what it means.
What Causes Other Period Symptoms in Early Pregnancy?
Many women can start to feel symptoms during early pregnancy that can be easily mistaken for PMS. This is due to the effects of the hormone progesterone, which increases during the luteal phase of your cycle (between when you ovulate and when your next period begins). It is responsible for both PMS symptoms and early pregnancy symptoms.
Shortly after implantation, your embryo will start to release hCG, which will make progesterone levels stay high. If you’re not pregnant, progesterone levels will fall, signaling for your body to begin shedding your uterine lining and start menstruation.
Either way, the progesterone in your body can cause a host of effects that make it difficult to tell whether you’re pregnant or you’re about to get your period. Some symptoms of early pregnancy that may be mistaken for PMS (or, on the flip side, symptoms of PMS that may be mistaken for early signs of pregnancy) are:
- Vaginal bleeding or spotting
- Breast sensitivity
- Lower back pain
- Irritability or mood swings
How Can You Tell the Difference Between Your Period and Pregnancy Spotting?
The short answer? You can’t. Many women experience vaginal bleeding during the luteal phase of their cycle, as well as during early pregnancy. Taking a pregnancy test is the only way to know for sure whether your spotting is because of pregnancy or because you’re about to get your period.
The best time to take a pregnancy test is 12 – 14 days past ovulation (DPO), which is around the time that most women would normally get their period.
Hasan R, Baird DD, Herring AH, et al. Patterns and predictors of vaginal bleeding in the first trimester of pregnancy. Annals of Epidemiology. 2010 Jul;20(7):524-531. DOI: 10.1016/j.annepidem.2010.02.006.
Hasan R, Baird DD, Herring AH, Olshan AF, Jonsson Funk ML, Hartmann KE. Association between first-trimester vaginal bleeding and miscarriage. Obstet Gynecol. 2009;114(4):860–867. doi:10.1097/AOG.0b013e3181b79796
E.W. Harville, A.J. Wilcox, D.D. Baird, C.R. Weinberg, Vaginal bleeding in very early pregnancy, Human Reproduction, Volume 18, Issue 9, September 2003, Pages 1944–1947, https://doi.org/10.1093/humrep/deg379