Use of Botox During Pregnancy

Most expectant mothers are aware of the harmful effects of alcohol and smoking during pregnancy. But what about Botox? Is Botox safe for pregnant women?

Botox is an injectable that contains botulinum toxin type A as the active ingredient. Commonly used for line reduction, Botox visibly reduces the look of forehead lines, crow’s feet, and glabellar lines between the eyebrows. Botox exerts its line-reducing effects by blocking the nerve cell signals. This helps to weaken and paralyze the muscles, diminishing the look of lines and wrinkles. In addition, Botox is also prescribed for a wide range of disorders and conditions such as urinary incontinence (resulting from detrusor overactivity due to multiple sclerosis or other neurologic conditions), spasticity, cervical dystonia, overactive bladder and blepharospasm.

Can I use Botox while I am pregnant?

Botox has been approved for cosmetic use in more than 78 countries around the world, including the United States, Canada, and many other countries in South America, Europe, and Asia. Despite its common use, there is a lack of studies on Botox injections in pregnant women. The main reason for the lack of evidence is insufficient volunteers. In order to measure the effects of Botox (or other aesthetic procedures) on pregnancy, researchers will need to perform tests on pregnant subjects. Very few patients are willing to undergo clinical trials during pregnancy (unless it is a life-saving drug). There is also a lack of animal studies on the effects of using botulinum toxin during pregnancy.

Is it safe for pregnant patients?

With the limited data, scientists cannot establish a causal relationship between maternal exposure to botulinum toxin A injections (e.g. Botox) and fetal harm. However, the general consensus is that botulinum toxin does not pass through the placenta. This may be due to the large size of the proteins. The molecular weight of botulinum toxin type A is found to be 150 kDa. In 1 of the studies, researchers could not detect any botulinum toxin in rabbits that received lethal doses intravenously. Data has shown that 8U/kg and 16U/kg of botulinum toxin may reduce the fetal body weights and cause reversible delayed ossification in mice and rats. Daily doses of botulinum toxin type A (0.125U/kg from day 8 to day 18 of gestation) have been shown to induce fetal malformations, abortions, and severe maternal toxicity in rabbits. Administration of 2U/kg of botulinum toxin A on day 6 and day 13 of gestation produces similar results.

Additionally, cases of botulism have been reported in pregnant patients who used botulinum toxin type A injections. There are cases where patients became completely paralyzed and required mechanical ventilation. Apart from these isolated cases, there is no clinical evidence of botulism. Furthermore, botulinum toxin could not be detected in infants’ serum. While some patients delivered slightly prematurely, others had a spontaneous labor at term. Therefore, researchers have hypothesized that botulinum toxin A injections (such as Botox) may prevent preterm labor in pregnancy after a fetal surgery.

To reach the placenta (and to exert an effect on the myometrium), the neurotoxin will need to diffuse from distant sites, e.g. facial musculature. Results of single fiber electromyography (EMG) have suggested the possibility of diffusion from distant sites. This is particularly evident when high doses of the neurotoxin are administered subcutaneously or intramuscularly. However, the diffusion seems to have little clinical significance, as there was no weakness observed in the muscles. Botulinum toxin type A is not known to diffuse into other distant sites such as contralateral musculature and the eye. It is unlikely that Botox can cause remodeling of motor units in the muscles or remote reinnervation. Based on the finding of in vitro studies, botulinum toxin type A may have a reversible inhibitory effect on myometrial activities. The long-term effect of Botox on unborn babies is unknown.

Can I use Botox anyways?

Due to the lack of credible evidence to prove its safety, it is generally not advisable to use Botox during pregnancy. In fact, most practitioners would advise their pregnant patients against using Botox, as it can potentially harm the mother and the fetus. As per the product label, pregnant patients should be aware of the potential risks of Botox (including fetal malformations and abortion) before using it. As a general rule, when the evidence is confusing or conflicting, the treatment should be avoided whenever possible. However, having a wide array of on- and off-label uses, it may not be possible to completely eliminate the use of Botox. Inadvertent exposure to Botox during pregnancy may be inevitable, especially when there is a medical condition. For instance, hemimasticatory spasms or other worsening conditions during pregnancy may necessitate the use of Botox. In these circumstances, it may not be possible to avoid using Botox altogether. However, the cosmetic use of Botox during pregnancy is usually not medically justified.

The bottom line

Patients should be able to make an informed decision. They should be made aware of all the risks involved in using Botox during pregnancy. At the same time, doctors should carefully consider all the potential adverse effects and benefits before starting a Botox treatment. Botox should only be used if the risks are outweighed by the potential benefits.