Subchorionic hematoma (SCH) and in vitro fertilization (IVF) are two medical concepts that can intersect during pregnancy. Understanding these conditions and their potential connection can provide clarity for those navigating pregnancy.
Understanding Subchorionic Hematoma
A subchorionic hematoma is a collection of blood that forms between the chorionic membrane and the uterine wall or developing placenta. This separation can vary in size and is often detected during early pregnancy. Vaginal bleeding, from light spotting to heavier clots, is a common symptom. However, some hematomas are discovered incidentally during routine ultrasounds without any symptoms.
Subchorionic hematomas are observed in 1% to 3% of all pregnancies and are a frequent reason for first-trimester bleeding. Many resolve spontaneously as pregnancy progresses. While most cases do not lead to serious complications, larger hematomas or those identified later in pregnancy can be associated with increased risks, such as premature labor or placental abruption.
Understanding IVF Treatment
In vitro fertilization (IVF) is an advanced fertility treatment that assists individuals in achieving pregnancy. The process begins with ovarian stimulation, where hormone medications encourage the ovaries to produce multiple eggs. Following this, egg retrieval collects the mature eggs. Once retrieved, the eggs are fertilized with sperm in a laboratory setting. The resulting embryos are monitored as they develop over several days, then one or more are transferred into the uterus using a thin, flexible catheter.
Why SCH is More Common with IVF
Subchorionic hematomas are observed more frequently in pregnancies conceived through IVF than in naturally conceived pregnancies. Studies indicate that the incidence of SCH in IVF pregnancies can be significantly higher, with reported rates ranging from 16% to 27%, compared to 11% to 13% in natural pregnancies. Several factors associated with the IVF process may contribute to this increased occurrence.
The hormonal environment created during IVF cycles, particularly fresh embryo transfers, is a contributing factor. Ovarian stimulation protocols in fresh cycles lead to elevated hormone levels, such as estrogen. These higher hormone levels may influence the uterine lining or blood vessel integrity, potentially making them more prone to minor bleeding and hematoma formation. Fresh embryo transfers often have a higher rate of SCH compared to frozen-thawed embryo transfers.
The embryo transfer procedure itself may also play a role. The gentle insertion of the catheter into the uterus to place the embryo could cause minor trauma or a slight separation of the delicate uterine lining, leading to a small blood collection. This mechanical aspect is considered a potential, though small, contributor to SCH development.
Beyond the procedure, the underlying reasons for infertility that necessitate IVF treatment might independently increase the risk of subchorionic hematoma. Conditions such as polycystic ovary syndrome (PCOS), hydrosalpinx, male factor infertility, adenomyosis, and a history of miscarriage have been identified as risk factors for SCH in IVF pregnancies.
Finally, increased medical surveillance common in IVF pregnancies can lead to a higher detection rate of subchorionic hematomas. IVF patients typically undergo more frequent and earlier ultrasound examinations to monitor pregnancy progression. This close monitoring allows for the identification of smaller or asymptomatic hematomas that might otherwise go unnoticed in naturally conceived pregnancies.
Outcomes and Management
For pregnancies complicated by a subchorionic hematoma, including those achieved through IVF, the general outlook is often positive. Most subchorionic hematomas, even those detected in IVF pregnancies, resolve on their own without leading to severe complications for the pregnancy. While some studies explore associations with outcomes like lower birth weight, comprehensive analyses suggest that SCH in IVF pregnancies does not significantly increase the risk of miscarriage or other adverse events.
Management of a subchorionic hematoma typically involves careful monitoring by healthcare providers. This often includes follow-up ultrasounds to track the hematoma’s size and resolution. Depending on the hematoma’s size and symptoms, a physician might recommend activity modifications, such as reducing strenuous physical activity or avoiding heavy lifting. Always follow your healthcare provider’s advice.