Blurred vision is a physical change that can occur during pregnancy, but it is generally not considered a reliable indicator or an early sign of conception. Instead, mild, temporary changes in vision are more often a side effect experienced later in pregnancy, typically during the second or third trimester, as the body undergoes physiological adjustments. These slight visual disturbances are usually benign and linked to the systemic hormonal and fluid shifts. Understanding the difference between these common, expected changes and sudden, severe symptoms is important for maintaining health throughout the pregnancy.
How Hormones Affect Vision During Pregnancy
The primary driver of mild vision changes during pregnancy is the fluctuation in hormones, particularly estrogen and progesterone. These hormones affect tissues throughout the body, including the eyes, by increasing the body’s tendency to retain fluid.
This fluid retention can cause a temporary, subtle swelling in the cornea, which is the transparent front surface of the eye. As the cornea thickens and its curvature slightly changes due to this extra fluid, the eye’s ability to refract light is altered. This results in mild refractive changes, causing temporary blurring or a slight shift in a person’s vision prescription.
Hormonal changes also affect the composition and stability of the tear film. This often leads to or worsens Dry Eye Syndrome (DES), a common condition during pregnancy. Symptoms of DES, such as grittiness, irritation, and intermittent blurry vision, are caused by a reduction in tear production or a change in tear quality. These expected, mild vision changes are temporary and resolve naturally within weeks or months after childbirth as hormone levels return to pre-pregnancy norms.
Other Common Causes of Blurry Vision
While pregnancy-related hormonal shifts can cause mild blurring, many people experience temporary visual fuzziness for reasons unrelated to gestation. General fatigue is a frequent cause, as is dehydration, which can be exacerbated by morning sickness and vomiting in early pregnancy.
Intense eye strain, often resulting from prolonged use of computer screens or digital devices, can lead to temporary difficulty focusing and visual discomfort. Additionally, some people experience an increase in migraine headaches during pregnancy, and these headaches can be preceded by a visual aura that includes temporary blurred vision, light sensitivity, or flashing lights. Any new or increased use of medication may also list mild blurring as a potential side effect.
Vision Symptoms That Require Immediate Medical Attention
Although most pregnancy-related vision changes are harmless, certain visual symptoms can signal a severe and time-sensitive complication. Sudden, severe, or persistent blurred vision should be evaluated immediately, as it can be a sign of preeclampsia. Preeclampsia is a disorder characterized by the sudden onset of high blood pressure, typically after 20 weeks of pregnancy, and damage to organs such as the kidneys or liver.
Vision disturbances are a common and serious manifestation of preeclampsia. These symptoms are caused by the high blood pressure affecting the blood vessels in the retina, the light-sensitive tissue at the back of the eye, or by swelling of the brain. Specific warning signs include the sudden onset of double vision, seeing persistent flashing lights, experiencing blind spots, or having dark spots or floaters that do not dissipate.
Another serious condition is gestational diabetes, which is high blood sugar that develops during pregnancy. Elevated glucose levels can cause the lens inside the eye to swell, leading to blurred vision. If uncontrolled, gestational diabetes can damage the small blood vessels in the retina, potentially leading to a condition called diabetic retinopathy. Any visual change accompanied by other severe symptoms, such as a persistent headache, pain in the upper right abdomen, or sudden, significant swelling of the face and hands, warrants immediate medical evaluation.
Consulting a Healthcare Provider
For mild, intermittent blurred vision or discomfort likely caused by dry eye or fluid retention, a consultation with an optometrist or ophthalmologist is appropriate. They can confirm that the changes are benign and suggest safe remedies, such as preservative-free artificial tears. It is important to delay getting a new vision prescription or having contact lenses refitted until after delivery, as the changes are temporary.
However, any sudden, severe, or persistent change in vision, particularly if it includes flashing lights or double vision, should prompt an immediate call to the obstetrician or a visit to emergency care. These severe symptoms require urgent medical assessment to rule out conditions like preeclampsia or poorly controlled gestational diabetes. Always ensure that any healthcare professional you consult is aware of your pregnancy status to guide appropriate diagnosis and treatment.