When pets are regarded as family members, their pregnancy periods are naturally "upgraded" to the "full-pregnancy management" for "expectant mothers". However, once female dogs or cats enter pregnancy, hormonal fluctuations, weight gain, and joint strain all lead to significant pain and discomfort. Traditional pain relief solutions rely on medications or anesthesia, yet drug therapy carries potential risks—any small molecule may cross the placental barrier, and anesthesia is even more likely to cause fetal respiratory depression. Thus, painless, non-irritating, and side-effect-free laser therapy has been frequently mentioned: it irradiates lesion tissues with light of specific wavelengths to trigger a series of photophysical and photochemical reactions, seemingly making it an ideal solution for pain relief during pregnancy.

Nevertheless, laser energy can be absorbed by cytochromes, thereby increasing mitochondrial ATP production and accelerating metabolism and microcirculation. If this "growth-promoting" effect acts on the uterus or placental tissues, it could theoretically alter local blood flow, raise temperatures, and even trigger changes in uterine tone, posing unknown risks to the fetus. As a result, two concurrent questions arise:

Can pregnant pets undergo laser therapy?

Can pregnant veterinarians perform laser therapy on pets?

This article will analyze from the dual perspectives of "pregnant pets" and "pregnant veterinarians" to help make sound decisions that balance "pain relief" and "ensuring pregnancy safety".

Understanding Laser Therapy

Lasers are categorized into two types: Low-Level Laser Therapy (LLLT) and High-Level Laser Therapy (HLLT). The key difference between them lies in power: lasers with power below 0.5W are classified as low-level lasers, suitable for treating superficial tissues; those with power above 0.5W are high-intensity lasers, applicable for treating deep tissues. Both can be used to relieve pain, reduce inflammation, and promote tissue healing. However, for pregnant patients, caution is paramount, and the safety of any therapeutic intervention must be thoroughly evaluated.

What Is the Role of Laser Therapy During Pregnancy?

1. Reducing Inflammation

Laser therapy can modulate the chemical factors in the body that participate in and mediate inflammatory responses, helping the body quickly move past the inflammatory phase.

2. Relieving Pain

Laser therapy regulates the levels of pain-transmitting substances in the body, such as bradykinin and serotonin, thereby alleviating pain.

3. Promoting Healing

Laser therapy stimulates the production of fibroblasts and osteoblasts in the body, as well as the formation of collagen, facilitating rapid tissue healing.

Can Pregnant Pets Undergo Laser Therapy?

Research suggests that pregnant pets can generally undergo laser therapy safely, provided that the uterine area is avoided—lasers can be directly applied to parts of the body other than the uterus, but direct irradiation of the uterus itself must be strictly prohibited. 

The reasons are as follows:

Lasers are high-intensity energy beams with strong directionality. When a laser acts directly on the uterine surface or adjacent tissues, its energy is absorbed by the tissues and converted into heat, which may cause a rapid local temperature rise. Under high temperatures, the myometrium and endometrium may experience edema, protein denaturation, or even necrosis, further affecting the normal implantation and development of the placenta and inducing miscarriage or premature birth.

Animal experiments and cytological studies have shown that any local energy (including gamma rays or lasers) may disrupt the "decidualization" process of endometrial stromal cells—a key step in placental vascular remodeling. If vascular remodeling is impaired, oxygen supply and nutrient delivery to the early placenta will be restricted, significantly increasing the risks of embryonic arrest, fetal growth restriction, and premature birth.

The first trimester of pregnancy is a critical period for fetal organ formation, during which cell division is extremely active and the fetus is highly sensitive to heat, photochemistry, and mechanical stress. If the uterus is irradiated with lasers during this period, even low-energy lasers may affect the fetus through maternal circulation or local inflammatory responses, theoretically leading to malformations or developmental disorders.

Can Pregnant Veterinarians Perform Laser Therapy on Pets?

Yes! A small amount of infrared laser light scatters back from the pet (patient). First, this scattered infrared laser is harmless. Second, the clothing worn by the pet (the transmittance of ordinary cotton T-shirts to lasers is < 0.01%) can completely block these residual scattered photons, so the actual energy received by the uterine area is negligible (effectively zero). Additionally, the electromagnetic radiation emitted by devices in the Vaymed series is lower than that of clock radios. The energy of infrared photons (E = hν ≈ 1.46 eV) is only 1/7 of the ionization threshold (≈ 10 eV); they cannot ionize molecules, so they are completely unable to break DNA strands or generate free radicals, and thus cannot damage tissues. Therefore, based on a comprehensive assessment of physical dosage, shielding effects, and biological mechanisms of action, this scattered infrared laser poses no measurable risks to pregnant veterinarians.

References:

[1] Safety of low-level laser therapy in pregnancy: a systematic review – de Sousa MVP, Kawakubo M, Ferraresi C, Hamblin MR. Lasers Med Sci. 2021;36(5):1005-1022. 

[2] Low-level laser therapy during pregnancy: maternal and fetal safety assessment in an animal model – Oliveira RF, de Freitas LF, Hamblin MR. Photodiagnosis Photodyn Ther. 2020;31:101829.