A chemical pregnancy is a very early pregnancy loss that occurs after a pregnancy test can detect human chorionic gonadotropin (hCG) but before the pregnancy can be confirmed on ultrasound. Because it happens so early, some people may mistake the bleeding for a late or heavier-than-usual period.1,2
Learning that a positive pregnancy test was followed by an early loss can be confusing and painful. Knowing what a chemical pregnancy means, why it may happen, and what usually comes next can help you feel more informed and supported.
Key Takeaways
- A chemical pregnancy is a very early pregnancy loss that occurs before a pregnancy can be confirmed on ultrasound.
- Sensitive home pregnancy tests have made chemical pregnancies more likely to be recognized, although many occur before someone realizes they’re pregnant.
- Many chemical pregnancies are believed to result from chromosomal abnormalities, although the exact cause often isn’t known.
- Signs of a chemical pregnancy include a positive test, followed by bleeding resembling a heavy period.
- Most chemical pregnancies resolve without a procedure, but follow-up care may be recommended to monitor hCG levels and rule out an ectopic pregnancy.
What Is a Chemical Pregnancy?
A chemical, or biochemical, pregnancy is a very early miscarriage that occurs shortly after implantation, before a pregnancy can be confirmed on ultrasound.1 Fertilization and implantation have occurred, but the pregnancy stops developing before an embryo or gestational sac can be seen on ultrasound.2
How Common Are Chemical Pregnancies?
Biochemical pregnancies are recognized more often today because highly sensitive home pregnancy tests may detect hCG several days before a missed period.2
Some studies estimate that up to 25% of pregnancies end before a missed period or before pregnancy symptoms develop.2 It’s entirely possible that you may not recognize a chemical pregnancy, especially if it occurs before a missed period.
Chemical pregnancies are also recognized more often during assisted reproductive technology (ART), including in vitro fertilization (IVF), because hCG levels are monitored closely with blood tests throughout treatment.2 Reported rates vary depending on the study and treatment protocol.2
Chemical Pregnancy vs. Clinical Pregnancy
A chemical pregnancy is in such an early stage of development that the diagnosis of pregnancy is only made due to circulating levels of human chorionic gonadotropin (hCG). A positive pregnancy test indicates that there’s enough circulating hCG in your urine to suspect pregnancy.2
A pregnancy is considered clinically confirmed when a gestational sac or embryo is visible on ultrasound.2 A clinically confirmed pregnancy may continue normally or may later result in a miscarriage, ectopic pregnancy, or delivery.
What Causes a Chemical Pregnancy?
Most early pregnancy losses are believed to result from chromosomal abnormalities. Other possible contributing factors include:2
- Uterine lining that’s too thin
- Sperm DNA damage
- Frozen embryo damage
Certain maternal health conditions and other factors have been associated with an increased risk of early pregnancy loss, including:1,5
- Advanced maternal age greater than 35
- Prior history of pregnancy loss
- First-trimester vaginal bleeding
- Autoimmune conditions
- Thyroid disease
- Obesity
- Diabetes
- Infections
- Uterine abnormalities
- Chronic stress
- Environmental contaminants
- IVF
Having one or more of these risk factors does not mean a chemical pregnancy will occur, and many happen without an identifiable cause.
Signs of a Chemical Pregnancy
One of the most common signs of a chemical pregnancy is a positive pregnancy test followed by bleeding that resembles a menstrual period or begins a few days later. Any bleeding following a very early miscarriage can be easily mistaken for a late or heavier-than-usual period.1 Mild cramping may also occur.1
Your obstetric provider may recommend repeat hCG testing and, when appropriate, an ultrasound to better understand what is happening. Because a chemical pregnancy occurs so early, an ultrasound may not yet show a gestational sac or embryo.1,2
When To Seek Urgent Care
Seek prompt medical care for severe or one-sided abdominal or pelvic pain, shoulder pain, dizziness, fainting, heavy bleeding, or symptoms that feel severe or rapidly worsen. These symptoms may indicate an ectopic pregnancy or another complication that needs urgent evaluation.3
Contact your healthcare provider whenever you have a positive pregnancy test followed by bleeding or pain, especially if the pregnancy location has not yet been confirmed.
Related: Ectopic Pregnancy: Symptoms, Causes, and Treatment
How Is a Chemical Pregnancy Treated?
A chemical pregnancy is considered an early pregnancy loss and often resolves without medication or a procedure because it occurs so early in pregnancy development.2 Your provider may recommend follow-up blood tests to ensure hCG levels are decreasing and to help distinguish a chemical pregnancy from an ectopic pregnancy.2 An ectopic pregnancy occurs outside the uterus and is considered a medical emergency.3
Can a Chemical Pregnancy Be Prevented?
Unfortunately, a chemical pregnancy isn’t preventable. You and your partner may naturally feel disappointment, guilt, and grief. However, chemical pregnancies are no one’s fault. A single chemical pregnancy also does not mean you have infertility or will be unable to have a healthy pregnancy in the future.2
Related: How to Help a Mom Who Has Experienced Loss
When Can You Try To Conceive After a Chemical Pregnancy?
Pregnancy loss can be devastating, especially if a chemical pregnancy occurs following fertility treatment. You may be wondering how long you should wait before trying to become pregnant again. Your healthcare provider can help guide that decision based on your individual situation, and current research does not clearly support a universal recommendation to wait several months after an early pregnancy loss.4
An equally important question is whether you and your partner feel ready to try to conceive again after the loss. Emotional healing after a loss looks different for every person and every couple. It’s an important first step after a miscarriage of any gestation. Some couples may be ready right away to try to conceive, while others may need some time. Seek support from your partner, family, friends, an obstetric provider, and a mental health professional, if needed, to support you (and your partner) through the grieving process.4
Related: How and When To Conceive After Pregnancy Loss
Early pregnancy loss can be incredibly difficult, and a chemical pregnancy can still bring real grief even though it happens so early. You’re not alone. Give yourself grace, lean on the people and resources that support you, and allow yourself (and your partner) as much time as you need to heal.
