A missed miscarriage is a type of pregnancy loss that occurs without outward signs or symptoms. In these situations, the embryo or fetus has stopped developing, but the body has not yet recognized the loss or expelled the pregnancy tissue.
What is a Missed Miscarriage?
A missed miscarriage, also referred to as a silent miscarriage, happens when the embryo or fetus is no longer viable but remains in the uterus. Unlike other types of miscarriages that often present with clear symptoms such as bleeding or cramping, a missed miscarriage typically lacks these overt signs. This absence of typical symptoms is due to the continued production of pregnancy hormones by the placenta, even after fetal demise. As a result, individuals may still experience common pregnancy symptoms like nausea, breast tenderness, or fatigue, and a pregnancy test might still show positive.
In some cases, a missed miscarriage can be an anembryonic pregnancy, also known as a blighted ovum. This occurs when a fertilized egg implants in the uterus and forms a gestational sac, but an embryo either never develops or stops developing at a very early stage and is reabsorbed by the body. The gestational sac and placenta continue to grow and produce hormones, leading to continued pregnancy symptoms and positive pregnancy tests, even though there is no developing embryo. This explains why the body does not immediately recognize and expel the non-viable pregnancy tissue.
How Long It Can Remain Undetected
The duration a missed miscarriage can go undetected varies significantly, ranging from days to several weeks, or even months, before it is discovered. This variability is influenced by individual physiological responses and the stage of pregnancy when the loss occurs. For some, the body may eventually recognize the loss and initiate the process of natural expulsion, but this can take an extended period.
Often, a missed miscarriage is diagnosed incidentally during a routine prenatal ultrasound scan. For instance, it might be discovered at the first trimester scan, typically between 11 and 14 weeks of gestation, or even later during the 20-week anomaly scan. The lack of a fetal heartbeat or an embryo that appears smaller than expected for the gestational age are common findings that lead to diagnosis. The timing of prenatal appointments, therefore, plays a role in how long the condition remains undiagnosed.
Subtle Indicators and Symptoms
While a hallmark of missed miscarriage is the absence of overt symptoms like heavy bleeding or severe cramping, some individuals might notice more subtle changes. One potential indicator is a sudden disappearance or significant reduction of typical pregnancy symptoms, such as nausea, breast tenderness, or fatigue. This can happen because the placenta may no longer be producing hormones at the same level as a viable pregnancy. However, it is important to note that pregnancy symptoms can naturally fluctuate in healthy pregnancies, so a decrease in symptoms alone does not definitively confirm a missed miscarriage.
Some individuals might experience mild cramping or light spotting, which may appear as brownish discharge. This can be easily overlooked or mistaken for normal early pregnancy spotting. Occasionally, a person might have an intuitive feeling that “something is wrong,” even without clear physical signs. These subtle signs are often non-specific, contributing to the “missed” nature of this type of miscarriage and emphasizing the importance of medical evaluation for confirmation.
Medical Confirmation and Next Steps
Medical confirmation of a missed miscarriage primarily relies on imaging, most notably ultrasound. During an ultrasound examination, a healthcare provider will look for a fetal heartbeat and assess the size of the embryo or gestational sac relative to the gestational age. A diagnosis of missed miscarriage can be made if an embryo with a crown-rump length (CRL) of 7 mm or more shows no cardiac activity, or if a gestational sac with a mean sac diameter (MSD) of 25 mm or more contains no yolk sac or embryonic pole. In cases where there is uncertainty, a follow-up ultrasound after a week or two may be recommended to confirm the lack of development.
Blood tests measuring human chorionic gonadotropin (hCG) levels can also provide supportive information. In a healthy pregnancy, hCG levels typically double every 48 to 72 hours in the first trimester. With a missed miscarriage, hCG levels may plateau, rise more slowly than expected, or begin to decline.
Once a missed miscarriage is confirmed, healthcare providers discuss management options, which include expectant management, medication, or surgical intervention.
Expectant management involves waiting for the body to naturally expel the tissue, which can take several weeks.
Medical management typically involves medication, such as misoprostol, which helps the uterus to contract and expel the pregnancy tissue.
Surgical options, like dilation and curettage (D&C), involve a minor procedure to remove the tissue from the uterus. The choice of management is made in consultation with a healthcare provider, considering the individual’s preferences and medical circumstances.