It’s a common enough scenario: You’re trying to get pregnant and think your period is late, only to experience a heavy flow a few days later. You may not realize it, but you might have just had what’s known as a chemical pregnancy, which is a very early miscarriage. Chemical pregnancy is actually quite common and often goes unnoticed. But with the rise of early-detection pregnancy tests also comes the rise of an awareness of early loss—and having to grapple with it. Here’s what you should know about chemical pregnancy and what it means for your future chances of motherhood.
What Is a Chemical Pregnancy?
A chemical pregnancy is a very early miscarriage that happens when a fertilized egg fails to properly implant in the uterus—usually before the fifth week of pregnancy. “If, on average, about 20 percent of pregnancies end in miscarriage, up to 75 percent of those miscarriages are chemical pregnancies,” says Sherry Ross, MD, a Santa Monica, California-based ob-gyn and author of She-ology: The Definitive Guide to Women’s Intimate Health. Period. Because it occurs so early on, chemical pregnancy refers to the loss of a pregnancy before the gestational sac would be visible through ultrasound, whereas a clinical miscarriage refers to the loss of a pregnancy that was visibly confirmed with ultrasound. “Most women who experience a chemical pregnancy never even knew they were pregnant,” Ross says. That’s because with the bleeding that usually accompanies it, a chemical pregnancy can just seem like a late, heavy period.
But if you’re trying to conceive and regularly taking pregnancy tests, a chemical pregnancy can throw you for an emotional loop. Since an embryo starts producing hCG (the hormone that pregnancy tests are designed to scan for) as soon as it initially implants in the uterus, a urine or blood test could display a positive result—only for the telltale heavy bleeding of chemical pregnancy to appear a week or two after the good news.
Chemical Pregnancy Causes
According to the American Congress of Obstetricians and Gynecologists (ACOG), about half of all early pregnancy loss is due to a random event where there’s an issue with the embryo’s chromosome count. Quick biology lesson: Chromosomes are the structures inside cells that carry genes. Normal cells have 46 chromosomes—23 that come from sperm, and 23 that come from the egg. But if an egg or sperm has too many or too few chromosomes, the embryo will wind up with a chromosomal abnormality and will fail to develop normally, sometimes ending in a chemical pregnancy. Other possible chemical pregnancy causes include:
- An infection, such as syphilis or chlamydia
- Abnormal hormone levels
- Thin or inadequate lining of the uterus
- Implantation outside of the uterus
The risk of chemical pregnancy increases if you’re over the age of 35 or dealing with certain medical issues, such as blood clotting and thyroid disorders. Unfortunately, there are no known ways to prevent chemical pregnancy.
Chemical Pregnancy Symptoms
This type of miscarriage happens so early on, you may not notice any chemical pregnancy symptoms at all. “Many women won’t be aware they’ve experienced a chemical pregnancy loss unless they’ve taken a home pregnancy test,” says Mark P. Trolice, MD, director of Fertility CARE: The IVF Center in Orlando, Florida, and author of From Infertility to Parenthood. “Often the woman just has a heavier period.” Other chemical pregnancy symptoms can include period-like uterine cramps in the days after a pregnancy test and passing clots of blood from the vagina.
Keep in mind, bleeding isn’t always a bad sign: In fact, light spotting can be a sign of successful implantation. “In the first trimester, 15 to 25 percent of pregnancies can experience vaginal bleeding,” Trolice says. “And while any bleeding may at first be alarming, unless the bleeding is heavy, it’s not associated with miscarriage.” Implantation bleeding, as it’s called, usually happens one to two weeks after ovulation and is “a completely normal sign of a healthy pregnancy,” Ross says. Still, if you have any of the symptoms above after a positive pregnancy test, even if it’s light spotting, call your doctor.
Getting Pregnant After Chemical Pregnancy
If you do experience a chemical pregnancy, the good news is that it’s absolutely possible to become pregnant afterward. “Actually, a chemical pregnancy is somewhat encouraging, because it shows that the woman’s partner’s sperm can fertilize her egg, and her uterus can call for embryo implantation,” Trolice says. “Fortunately, the prognosis is good for an ultimately successful pregnancy and baby.”
In fact, a woman may ovulate and get pregnant as soon as two weeks after experiencing a chemical pregnancy. “Since a chemical pregnancy is an early miscarriage, your chances of a healthy pregnancy are likely after having one miscarriage,” Ross says. “A woman’s risk of miscarriage ranges from 10 to 50 percent, depending on a woman’s age, with the average risk being around 15 percent. Only 2 percent of women will experience two miscarriages in a row.”
There’s no medical reason to delay trying to conceive after a chemical pregnancy. “Once hCG levels decline and the woman has a subsequent period, she can resume trying to conceive,” Trolice says. In fact, women may be more fertile following a chemical pregnancy: A recent study found that women who tried to get pregnant within three months of a lost pregnancy were 17 percent more likely to conceive and have a live birth than those who waited longer.
The Emotional Toll of Chemical Pregnancy
While chemical pregnancy may go unnoticed for some, an early miscarriage can take an emotional toll for those who are aware of the loss, especially if they had been trying to conceive for a while. “A chemical pregnancy can be as devastating as a clinical miscarriage, so the woman needs appropriate support from her partner and loved ones,” Trolice says.
Feelings of sadness, anxiety and guilt are common after experiencing a chemical pregnancy, says Aparna Iyer, MD, a perinatal psychiatrist and assistant professor at the University of Texas Southwestern Medical Center in Dallas. “Many encounter emotional fears that they may have somehow caused the loss, even when they recognize intellectually that this isn’t true,” she says. Some of her patients have been surprised at how strongly they reacted, since the pregnancy did not last long. “However, a loss is a loss,” Iyer says, “and losing a pregnancy is a significant loss for many.”
How a woman wants to open up about her chemical pregnancy is up to her, but “struggling alone is rarely the healthiest option,” Iyer says. “I’d suggest she consider sharing it with the people closest to her, those who are most willing to support her and let her fully express herself without any fears of judgment.”
It’s understandable to hesitate before getting pregnant after chemical pregnancy, but “it’s important to acknowledge and confront those fears. An important way to work through the fears is to speak candidly with your physician,” Iyer says. “Having a medical view of what to expect can help set your expectations and help you work through anxiety.”
Published September 2017