10 Possible Causes of Abnormal Vaginal Bleeding

Spotting when you’re trying to conceive can strike fear in your heart. Is this bad? Could it be good? Is this implantation spotting, an early sign of pregnancy? Or just the start of my period? If you’re going through fertility treatments—especially IUI or IVF—your odds of experiencing spotting are higher.

There are many possible reasons for abnormal vaginal bleeding or spotting. Keep reading to learn more about implantation spotting, spotting and early miscarriage, and spotting that has nothing to do with early pregnancy.

Implantation Spotting

Light spotting that occurs between ovulation and your expected period is sometimes referred to as “implantation spotting.” The theory most commonly repeated online is that when an embryo implants itself into the uterine lining, the lining in that area sheds just slightly, leading to what you later see as light spotting.

There is no proof that is what’s actually occurring. It’s also unlikely. (Consider how very tiny an embryo is, and how very tiny any lining in that area may be, and you’ll see how this theory is far fetched.) However, it could be that the embryo implanting itself into the lining does trigger a hormonal reaction that leads to very light spotting.

Women receiving fertility treatments may be more likely to spot. It's unclear if spotting is a sign of early pregnancy.

One study found that women taking a particular form of progesterone were more likely to experience spotting than those taking another form. While spotting was more common in one group, the pregnancy rates were similar. In other words, spotting was neither a good nor bad sign in this study.

Start of Miscarriage

If the spotting occurs after a positive pregnancy test, you might worry that it is the start of an early miscarriage. But spotting during early pregnancy isn’t uncommon. Spotting after a positive pregnancy test doesn’t mean you’re miscarrying.

About 50% of people who have vaginal bleeding during the first three months of pregnancy will continue their pregnancy. While 50% doesn’t sound like great odds, it’s clear that spotting doesn’t absolutely mean you will miscarry. There’s a good chance things will be fine.

Personally, I have had spotting during a healthy pregnancy, a healthy pregnancy with no spotting, and spotting that led to a miscarriage. I couldn’t tell you the difference between those three experiences.

Make sure to call your healthcare provider if you have any sort of vaginal bleeding after getting a positive pregnancy test. They may want to run some blood work, order an ultrasound, or prescribe progesterone support (if you’re not already taking it).

If you don’t have a history of infertility or miscarriage, your healthcare provider may do nothing and suggest relaxation. If things get worse, though—or you begin to experience cramping or pain—call again.

Other Reasons for Spotting

Spotting can occur for reasons besides early pregnancy. A few possible causes include:

• Hormonal imbalance: Spotting may occur more often in premenopausal people, for example. Thyroid problems and birth control medications can also lead to spotting between cycles.
• Fibroids or polyps
• Side effects of fertility drugs: Many fertility drugs, including Clomid, list spotting as a possible side effect.
• Progesterone suppositories
• Gynecological procedures, such as a pap smear
• IUI or IVF procedures
• Transvaginal ultrasound: The wand can bump into the cervix, which may lead to light spotting. Also, if you’re taking fertility drugs or progesterone, your cervix is more sensitive, which makes spotting more likely.
• Sexual intercourse: If the cervix gets hit, it can lead to light spotting in some cases. This may be more likely if you’re taking fertility drugs.

When to Worry

Occasional spotting between periods is nothing to worry about. However, there are times you should call a healthcare provider.

Frequent Spotting

Check with your healthcare provider If you frequently experience spotting between periods or before your period starts. Spotting for 2 or more days before your period actually starts is associated with endometriosis.

Spotting can also be a symptom of an infection, a hormonal imbalance, fibroids, and, in rare cases, some cancers. Get it checked out if you frequently spot between cycles.

Heavy Bleeding

If you’re pregnant and experience heavy bleeding, this is concerning. If you start to have a flow that is more similar to your period or the spotting transitions to a heavier flow, you should contact a healthcare provider.

Cramps With Spotting or Bleeding

When spotting or bleeding is accompanied by pelvic pain or cramps, contact a healthcare provider. Mild cramps or general achiness can be normal during early pregnancy, as well as during your period. Really bad cramps are not normal.

If you’re pregnant, spotting, and having even mild cramps, call a healthcare provider. They may simply reassure you that what you’re experiencing is normal, or choose to run some blood work or an ultrasound. But it’s better to call than assume everything is fine. 

Severe Pain

If you’re experiencing severe pain, go to the nearest emergency room and contact your healthcare provider immediately.

Vaginal bleeding with severe pain could indicate an ectopic pregnancy, or, if you’ve taken fertility drugs, a complication of ovarian hyperstimulation syndrome (OHSS). It can also be a sign of acute pelvic inflammatory disease. Get medical attention as soon as possible.