I Got My Period Twice This Month—What Gives?

Normal Pregnancy

Both Dweck and Ordeberg agree that normal pregnancy may cause bleeding outside of the typical period schedule. “The uterus may bleed when the fertilized egg attaches,” Ordeberg explains. “The bleeding is called implantation bleeding and can occur sometime between weeks two and three of pregnancy (when one does not know one is pregnant and might think that one’s had a period twice in one month). During pregnancy, spotting can also happen due to the fact that there is a higher blood flow in the cervix.”

Data suggests that it is not uncommon for a person with female reproductive organs who is extremely early in their pregnancy to spot, typically before they are even aware that they are pregnant and carrying.2

Miscarriage

Miscarriages can cause bleeding “between periods” if the miscarriage is prior to missing a menstrual period. Studies show that between one third to half of all pregnancies end in miscarriage prior to the person knowing they are pregnant, which leads to the potential of mistaking it as a second period that month.3

However, bleeding during pregnancy does not always mean miscarriage. Bleeding can be common in early pregnancy and typically impacts about one-fifth of pregnant people in their first trimester.4

Ectopic Pregnancy

Ectopic pregnancy, which is when a fertilized egg implants on tissue other than the lining of the uterus, can cause abnormal bleeding.5 The fertilized egg implants on a structure that can’t support its growth; this typically happens in the fallopian tube, but in rare cases can occur on an ovary or in the abdominal cavity.6

If a person experiences bleeding when pregnant, it’s important to consult an OB/GYN right away for evaluation and to rule out an ectopic pregnancy early.7 It’s also important to note that ectopic pregnancy is a life-threatening condition that can be very dangerous.

Missed Birth Control Pills

Birth control can be tricky even when taken consistently on time, but missed birth control pills can pose a bigger issue. Experts say that if you miss more than three pills in a row, it is likely that you will bleed. If you are using birth control as a contraceptive, it is strongly recommended you use backup protection if you miss a day, as the pill may be ineffective at preventing pregnancy due to the disturbance in schedule. Consult your OB/GYN for further instructions.8

While birth control is also typically used as a tool to maintain your period schedule, experts note that unscheduled bleeding is one of the main reasons cited by those choosing to stop their birth control method.9 It’s important to note that spotting and bleeding between periods is possible, even when you take your birth control on schedule. “Spotting often occurs during the use of the contraceptive pill, especially during the first months of use,” says Ordeberg. “Spotting is also common during the first three months of using hormonal IUDs.”

Polycystic Ovary Syndrome

Polycystic ovary syndrome, often known by its abbreviated name PCOS, is a hormonal disorder. With PCOS, ovaries produce abnormally high levels of androgens, which cause the reproductive hormones to become imbalanced. This, in turn, causes irregular menstrual cycles.10

At this time, the exact cause of PCOS remains unknown, but hereditary gene traits are thought to be linked.11

Thyroid Dysfunction

Thyroid glands produce hormones and are therefore important for regulating the menstrual cycle. If the thyroid does not function properly and creates too little of hormones, known as hypothyroidism, it can cause periods to be more frequent and heavier.12

Those assigned female at birth (AFAB) are more likely to have thyroid issues than those assigned male, and one in eight AFAB people will experience thyroid issues in their lifetime. Beyond menstrual issues, which include the possibility of bleeding twice in one month, thyroid problems can lead to problems during pregnancy as well as difficulties getting pregnant to begin with. Hypothyroidism can be treated with medicine that helps balance the hormones your body needs to work normally.13

Cervical Polyp

Cervical polyps are abnormal growths in the cervix. While they are commonly benign and typically asymptomatic, they can cause abnormal uterine bleeding such as heavy menstrual bleeding, intermenstrual bleeding, or postmenopausal bleeding.

These growths are typically seen during the reproductive years. Cervical polyps are often discovered in routine GYN checkups, and may or may not need intervention depending on the circumstances. Consult your OB/GYN for the next steps.14

Uterine Polyps

Uterine polyps are growths that occur in the inner lining of the uterus. While they are typically (but not always) noncancerous, they can cause problems with menstruation and fertility. Uterine polyps are formed by the overgrowth of endometrial tissue and attach to the endometrium, extending inward towards the uterus.

Uterine polyps can cause irregular menstrual periods which include excessive bleeding and bleeding between periods, making them one of the potential causes of bleeding twice in one month. While there is no way to prevent uterine polyps, they can be treated with medication if deemed necessary by your doctor.15

Perimenopause

Perimenopause, sometimes known as menopause transition, is exactly that—the time when your body is transitioning to menopause. During perimenopause, your ovaries begin to produce fewer hormones, which leads to the menstrual cycle becoming more irregular and inconsistent, hence the potential to bleed twice in one month. It is during this time that your body is shifting toward the end of your reproductive years, and the timeframe is typically four to eight years. The timing of perimenopause can differ drastically person-to-person, with some experiencing it as early as their mid-30s and others as late as their mid-50s.16

While bleeding twice in one month is normal during perimenopause, it’s a wise idea to confirm that what you’re experiencing is, indeed, perimenopausal bleeding. “Any irregular bleeding patterns when someone is older than the age of 40 and nearing menopause need to be evaluated by a physician,” says Klimczak. “Most OB-GYNs will recommend an endometrial biopsy to rule out endometrial cancer, which can present as abnormal and/or irregular bleeding.”

Medication-Induced

Medication-induced vaginal bleeding can go beyond birth control. Studies have uncovered vaginal bleeding as a side effect of medications such as blood thinners. Bleeding may occur outside of the period, resulting in the potential to bleed twice in one month.17 Additionally, Klimczak says that some antibiotics, seizure medications, and fungal medications can speed up the metabolism of birth control pills, which may result in bleeding.

Experts say you should consult a doctor if you find yourself bleeding vaginally after starting a new medication or hormone treatment.

Uterine Cancer

Uterine cancer, which generally describes cancers of the uterus, can typically be broken into two categories: endometrial cancer and uterine sarcoma. Both forms of uterine cancer can cause heavier periods and bleeding between periods. The majority of uterine cancers are diagnosed early due to the presence of abnormal uterine bleeding.18

Klimczak re-iterates the importance of seeing a doctor for any abnormal bleeding if you’re over the age of 40, or younger if you have additional risk factors such as PCOS. “Most OB-GYNs would recommend an endometrial biopsy to rule out endometrial cancer,” she says. “An endometrial biopsy is a minimally invasive procedure where your OB-GYN will use a small catheter to take a sample of the uterine lining. It is a quick procedure that can be done in the doctor’s office and other than some cramping has very few side effects.”

Experts say that those who get their period before age 12 are at higher risk for uterine cancer, as well as those who have still not experienced menopause at age 50. Endometrial cancer is the most common cancer affecting the female reproductive system in the U.S., with about 3 percent of women being diagnosed in their lives. As with many cancers, treatment for uterine cancers includes chemotherapy, as well as radiation therapy, hormone therapy, and surgery.19

Excessive Stress

Excessive stress often will have negative effects on the mind and body. In the category of body, it can impact the menstrual cycle—and cause abnormal cycle schedules as a result, according to Dweck. The abnormalities typically stem from cortisol, the hormone your body makes when you’re under stress.

It is recommended that you see a doctor if you have three or more abnormal periods, including bleeding twice in one month.20

Uterine Fibroids

Often confused with uterine polyps, uterine fibroids are noncancerous growths of the uterus. Uterine Fibroids can grow on the outer surface of the uterus, the inside of the uterus, and within the muscle wall of the uterus. While they often go undetected due to lack of symptoms, symptoms can include more frequent, longer, and heavier periods as well as bleeding between periods. Bleeding between periods can often be mistaken as a “second period.”21

Fibroids are not uncommon among women—by age 50 almost 70 percent of white women and over 80 percent of Black women will have developed a fibroid. Like polyps, fibroids can be asymptomatic but often cause discomfort and pressure symptoms. Many women with fibroids will experience abnormal uterine bleeding as well as iron-deficiency anemia.22