Finding out your pregnancy is nonviable can be one of the most devastating experiences for an intended parent. Adding to this pain are the multiple — and sometimes confusing — ways pregnancy loss can manifest in the first place.
Words like “miscarriage,” “spontaneous abortion,” and “early pregnancy loss” tend to be used interchangeably to describe a nonviable pregnancy within the first 12 weeks. But there’s another term that’s also synonymous with pregnancy loss called a chemical pregnancy that denotes a specific type of early miscarriage.
So, what is a chemical pregnancy?
“A chemical or biochemical pregnancy is a pregnancy where we only have an elevated beta human chorionic gonadotropin (HCG) level, which is measured with a blood test,” explains Levica Narine, M.D., FACOG, an OB/GYN Fertility Specialist at Kofinas Fertility Group in New York. “We won’t see evidence of a pregnancy on an ultrasound.” The term “chemical pregnancy” comes from the chemicals in your body, or hormones, that produce a positive result on a pregnancy test.
This form of pregnancy loss occurs when an embryo forms — and implants in the uterus — but then stops developing shortly thereafter. Since a chemical pregnancy is a very early miscarriage that happens within the first five weeks of pregnancy, patients may not even realize they were pregnant at all.
Rescripted spoke with Dr. Narine at length to help us better understand why a chemical pregnancy occurs, who is at risk for one, and how a chemical pregnancy differs from a more noticeable miscarriage. Read on for her insights below.
How is a chemical pregnancy different from a miscarriage?
The main difference between a chemical pregnancy and a miscarriage is that in the case of a miscarriage, “there is a visualization of a pregnancy using an ultrasound,” says Dr. Narine. A chemical pregnancy cannot be found on an ultrasound.
A chemical pregnancy, as opposed to a miscarriage, can be difficult to determine because there aren’t any distinctive symptoms. “[Patients] may only notice a slight delay in their menses,” says Dr. Narine. “That is why a chemical pregnancy is sometimes called a ‘menstrual miscarriage.’”
With a “conventional” miscarriage, there is evidence of pregnancy on an ultrasound, as well as more discernible pregnancy-related symptoms such as nausea, vomiting, breast tenderness, bloating, and constipation. These symptoms are more prevalent because “the pregnancy hormone level will be much higher,” says Dr. Narine.
If a patient has a miscarriage, they “will usually have bleeding and cramping that is not [typical] after a pregnancy has been well established,” says Dr. Narine. A chemical pregnancy, on the other hand, “may present as normal menstrual bleeding or a mildly delayed menstrual cycle.”
Why does a chemical pregnancy typically occur?
Dr. Narine says there are several reasons why a chemical pregnancy might occur: Egg quality (which leads to issues with embryo quality) related to age, congenital abnormalities of the uterus, such as a septate uterus or bicornuate uterus, or uterine pathology including fibroids, endometrial polyps, or chronic endometritis (aka inflammation within the uterine cavity).
“These physical conditions may all lead to a poor implantation environment, so the pregnancy never becomes well established,” explains Dr. Narine. “Hence the low pregnancy hormone levels that do not progress to higher levels where we may see something on the ultrasound.”
Who is at risk for a chemical pregnancy?
There are several factors to consider when growing your family, including your risk for chemical pregnancy. So getting on top of your medical history before trying to conceive is always wise. Women who are older and may have poorer egg quality are at a higher risk for chemical pregnancy, says Dr. Narine, as well as those with fibroids, adenomyosis, and uterine malformations.
There is also a higher risk of a chemical pregnancy in people with underlying medical conditions like diabetes, obesity, hypertension, and autoimmune diseases. Lifestyle choices like heavy drinking, cigarette smoking, vaping, recreational drug use, and an unhealthy diet can also increase your risk for chemical pregnancies.
What happens after a chemical pregnancy?
If you’ve endured a chemical pregnancy, your healthcare provider will first “make sure the pregnancy hormone levels decline to zero,” says Dr. Narine. This is to confirm “the pregnancy has been cleared.” She also recommends having an ultrasound to “evaluate the uterine cavity” and to check if “there are any uterine malformations such as fibroids or polyps.” If fibroids or polyps are discovered, “there would be a consideration for surgical removal to improve the uterine cavity.”
The good news for those who have had a chemical pregnancy (or miscarriage) is that you can still have a successful pregnancy. But Dr. Narine advises patients to take important risk factors into account such as age, uterine pathology, and treatment of uterine cavity inflammation. Patients may also want to discuss ruling out infectious diseases, as well as testing for autoimmune factors that could lead to miscarriages with their healthcare provider before trying to conceive again.
For women 35 and older, Dr. Narine recommends seeking medical attention even if you've only had one chemical pregnancy or miscarriage, because “the probability of fertility issues increases with age.” This also goes for anyone experiencing difficulty getting pregnant several months after a chemical pregnancy, or if you’ve had recurrent chemical pregnancies (two or more).
But the best way to understand your risk for chemical pregnancy and miscarriage is to be an active participant in your medical care. That means having a two-way discussion with your healthcare provider about diagnostic testing. “Women should be their own advocates for AMH testing, infectious disease testing, genetic testing, autoimmune testing, and imaging studies such as ultrasounds and MRIs,” says Dr. Narine. Pushing for additional testing “could help reveal the reason for a miscarriage/chemical pregnancy," giving you much-needed peace of mind as you consider next steps.
Sarene Leeds holds an M.S. in Professional Writing from NYU, and is a seasoned journalist, having written and reported on subjects ranging from TV and pop culture to health, wellness, and parenting over the course of her career. Her work has appeared in Rolling Stone, The Wall Street Journal, Vulture, SheKnows, and numerous other outlets. A staunch mental health advocate, Sarene also hosts the podcast “Emotional Abuse Is Real.” Visit her website here, or follow her on Instagram or Twitter.