Chemical pregnancy: What is it and why does it happen?

Everything you need to know if you've experienced a chemical pregnancy.
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  • A chemical pregnancy is a miscarriage that occurs in very early pregnancy. We look at how to spot symptoms of a chemical pregnancy and what can be done to prevent it.

    What is a chemical pregnancy?

    A chemical pregnancy is a miscarriage that occurs in very early pregnancy. This type of miscarriage is called a chemical pregnancy because levels of the hormone human chorionic gonadotropin (hCG) are initially elevated enough to produce a positive result on a pregnancy test. However, the chemical levels drop again before a doctor can see the gestational sac on an ultrasound.

    In this article, we explore the signs and symptoms of a chemical pregnancy, and how to reduce the risk:

    How likely is a chemical pregnancy – and when does it happen?
    How do you know if you’ve had a chemical pregnancy?
    What are the symptoms?
    What causes a chemical pregnancy?
    Is a chemical pregnancy a miscarriage?
    How long does chemical pregnancy bleeding last?
    Will I be fertile after a chemical pregnancy?
    Can you prevent it?
    Where to find support

    How likely is a chemical pregnancy – and when does it happen?

    According to the American College of Obstetricians and Gynecologists, chemical pregnancies account for around 50 to 75 percent of miscarriages. It is also thought to occur in as many as 50 to 60 percent of first pregnancies.

    Chemical pregnancies usually occur in the first few weeks of pregnancy. It can happen so early on in a pregnancy that it’s easily confused with a period or an unusual menstrual cycle. Chemical pregnancies are a type of miscarriage that differ from other miscarriages. While miscarriages can occur at any time during a pregnancy, a chemical pregnancy always occurs shortly after implantation. This could be within just days of getting a positive pregnancy result.

    One common theme with chemical pregnancies, according to Dr. Jeffrey Sternberg, founder of The Fertility Institutes, is that ‘many women fail to notice a chemical pregnancy, or tend to blame it on their menstrual cycle.’

    Chemical pregnancy pregnancy test

    Credit: Getty Images/iStockphoto

    How do you know if you’ve had a chemical pregnancy?

    The clearest sign of a chemical pregnancy is a positive pregnancy test result that is followed by a negative one.

    Dr Katie Morris, is reader in maternal fetal medicine at the University of Birmingham and researcher at women’s health research charity Wellbeing of Women. She explains that you may discover a chemical pregnancy during an ultrasound: “Some women may have all the symptoms and signs of a normal early pregnancy and so do a pregnancy test that is positive. But an ultrasound shows no signs of a pregnancy.”

    Because chemical pregnancies occur so soon after implantation takes place, many women show very few symptoms, if any at all.

    What are the symptoms?

    If women do experience symptoms, they may include:

    • mild spotting a week before an expected period
    • abdominal cramping, which is normally mild
    • vaginal bleeding that occurs close to the time of an expected period or shortly afterward.

    This kind of early-stage miscarriage usually doesn’t require medical intervention. However women who experience one are encouraged to follow up with tests to ensure that their hCG levels return to normal.

    You should also confirm that you do not have an ectopic pregnancy. Dr Hannan Al-Lamee, clinical research fellow at the Hewitt Fertility Centre explains: “If the pregnancy test is positive and there is no evidence of a pregnancy within the uterus on the ultrasound, this could also indicate an ectopic pregnancy. This can be dangerous and should be excluded.”

    What causes a chemical pregnancy?

    It is not always possible to determine the exact cause. Some potential causes or contributing factors include the following:

    • Chromosomal abnormalities. These are the leading cause of early pregnancy loss. Irregularities in chromosomal arrangements may prevent the foetus from developing.
    • Uterine abnormalities. Presence of irregularities in the uterine lining can prevent the embryo from implanting in the uterus.
    • Insufficient hormone levels. The body needs higher levels of a particular hormone, such as progesterone, to support the development of the foetus.
    • Low body mass index (BMI). Underweight women are more likely to have an early miscarriage.
    • Advanced maternal age. Women of 35 years or older may find it harder to get and stay pregnant.

    Is a chemical pregnancy a miscarriage?

    Yes, it is a form of early-stage miscarriage. However, since symptoms are often only period-like cramping and bleeding, some women may understandably confuse this miscarriage with their menstrual cycle.

    How long does chemical pregnancy bleeding last?

    This depends on the individual. Bleeding and cramping can last anything from a few hours to a week. If you are concerned about ongoing bleeding, you should speak to your midwife or doctor immediately.

    Will I be fertile after a chemical pregnancy?

    Yes. People with a history of pregnancy loss can still go on to have other healthy pregnancies and carry babies to full term. “Many women who experience a chemical pregnancy go on to have a normal pregnancy,” says Lesley Gilchrist, Registered Midwife and Founder of My Expert Midwife. “However if you experience more than two chemical pregnancies, you can seek more detailed advice from your doctor surrounding your individual circumstances.”

    Whilst a chemical pregnancy can feel like an immense loss, it still demonstrates that your eggs can be fertilised and the uterus can initiate implantation. As long as you feel emotionally ready, there is no medical reason to delay trying to conceive again.

    In fact, a study from the National Institutes of Health recommends trying again within three months. Their research demonstrated that women who tried to get pregnant within three months of a miscarriage had 17 percent more chance to conceive and have a live birth than those who waited.

    Can you prevent it?

    Because most chemical pregnancies occur due to abnormalities in the chromosomes, there is nothing specific that can be done to prevent them. One vital step, however, is to lead a healthy lifestyle. Including:

    • Eating a healthy, balanced diet
    • Eating iron-rich food
    • Avoiding smoking and excessive amounts of alcohol
    • Proper and regular exercise
    • Stress management
    • Monitoring weight and keeping it within healthy limits
    • Regular sleep and relaxation
    chemical pregnancy

    Credit: Getty Images

    Where to find support

    Losing a child at any stage can cause a great deal of grief, anxiety and distress. According to a study from Imperial College London published in the American Journal of Obstetrics and Gynaecology, nearly a third of women (29%) suffered post-traumatic stress following miscarriage, early pregnancy loss or ectopic pregnancy.

    You are not alone. If you’re having trouble coping with your loss, or you know someone who is, then seek to speak to a doctor, counsellor or recognised support group. It’s vital to remember that nobody is to blame for a chemical pregnancy. In most cases, they are totally out of the expectant mother’s control.

    Find a chemical pregnancy forum

    There are many online groups and chemical pregnancy forums where you can share your experiences and find support:

    • Miscarriage Association has a pregnancy loss forum and private Facebook groups for people to safely discuss their miscarriage experiences and lend support to one another. You can also call their helpline 9am-4pm, Monday – Friday (01924 200 799).
    • Tommy’s runs #MisCourage an online campaign that allows women to share their own stories of miscarriage. Midwives trained in bereavement support run their helpline from 9am-5pm, Monday – Friday (0800 0147 800).