OnabotulinumtoxinA for chronic migraine during pregnancy: a real world experience on 45 patients

DOI: https://doi.org/10.1186/s10194-020-01196-1

Abstract-Summary To report the pregnancy outcomes on patients with chronic migraine exposed to onabotulinumtoxinA from Hull Headache Clinic.

OnabotulinumtoxinA is approved as preventive treatment for adult patients with

chronic migraine, although its impact on pregnancy is unknown.

Female patients of reproductive age group receiving onabotulinumtoxinA are given advice on contraception and the unknown impact of the toxin on pregnancy.

All patients are consented for access to their medical records and pregnancy

outcome and those who wished to continue are asked to sign a disclaimer.

Pregnancy outcome data was collected on all patients for the mode of delivery,

birth weight and congenital malformation and any other unexpected outcomes.

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4 Treatment

Over 9 years period 45 patients reported pregnancy while receiving onabotu- linumtoxinA. All patients had received onabotulinumtoxinA within 3 months prior to the date of conception.

Thirty-two patients wished to continue treatment during pregnancy while the

remaining 13 stopped treatment.

We report our experience of 45 patients exposed to onabotulinumtoxinA during

pregnancy.

Although the numbers are small, there was no impact of the toxin found on the

pregnancy outcomes.

Extended: A similar foreseeable challenge is the evaluation of onabotulinum- toxinA injections in lactation, particularly if more patients consent to have treat- ment through their pregnancies in the future.

Introduction Migraines are common in women of reproductive age and its control may deterio- rate although 50–75% of female migraineurs experience a marked improvement during pregnancy with a significant reduction in frequency and intensity of their attacks, if not a complete resolution [446].

There is limited evidence demonstrating safety and efficacy of the oral preventa- tive agents in pregnancy with only amitriptyline and low propranolol deemed suit- able for use [447].

OnabotulinumtoxinA has been the established treatment for chronic migraine in

the UK where 3 or more oral preventative agents have failed [448].

We report our experience of 45 pregnant patients receiving onabotulinumtoxinA

(Botox) for chronic migraine from a tertiary centre (Hull) in the UK.

Methods All patients receiving onabotulinumtoxinA for chronic migraine received prospec- tive follow up and women of reproductive age were informed about the uncertain impact of onabotulinumtoxinA on pregnancy and were given advice on contraception.

Patients receiving onabotulinumtoxinA who reported pregnancy were given an informed discussion about the limited understanding of its impact on pregnancy and any teratogenicity that it may cause.

Patients continuing onabotulinumtoxinA injections followed the original 12

weekly cycles of injections.

Headache diaries were completed before and after treatment as means of moni- toring the therapeutic response to onabotulinumtoxinA to determine if the treatment were to continue or stop.

Results During the period 2010–2019, 45 patients were exposed to onabotulinumtoxinA for migraine during pregnancy.

Of the 32 cases who consented to receive onabotulinumtoxinA continued to

show a good treatment response.

All patients were exposed to onabotulinumtoxinA within 3 months of conceiving.

4.5 Pregnancy

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Of the 32 cases consented to continue the treatment during pregnancy, 1 patient had a miscarriage and remaining delivered full term of which there were 2 forceps and 3 caesareans.

She was fit and healthy with no medical problems, a non-smoker who drinks alcohol occasionally and had two previous pregnancies with full term normal vagi- nal deliveries.

She continued treatment with onabotulinumtoxinA during pregnancy and after

miscarriage.

She continued onabotulinumtoxinA treatment in the second pregnancy as well. Those who stopped were all full term deliveries of which there were 1 forceps

assisted and two caesareans planned due to difficult previous vaginal deliveries.

Discussion The 32 patients who remained on treatment with onabotulinumtoxinA through pregnancy continued to show a good response whilst 11/13 who withdrew from treatment showed a relapse in their condition.

There is only 1 case report in the literature of onabotulinumtoxinA treatment for

chronic migraine during pregnancy [449].

In this US study, a 26-year-old migraineur was treated with onabotulinumtoxinA

but later chose to discontinue this because of the unknown risks in pregnancy.

A 24-year retrospective study of the Allergan global safety database reviewed

574 onabotulinumtoxinA treatments in pregnancy [450].

It is also worthy to note that 96% of all cases exposed to onabotulinumtoxinA in this study occurred either prior to conception or during the first trimester and so the effects of injections in the second and third trimester remain largely unknown.

Conclusion The current study reports our experience of onabotulinumtoxinA for chronic migraine in 45 pregnancies.

The numbers are small to draw a conclusion of safety and therefore, it is impor-

tant to set up a toxin pregnancy register like the one in epilepsy.

A similar foreseeable challenge is the evaluation of onabotulinumtoxinA injec- tions in lactation, particularly if more patients consent to have treatment through their pregnancies in the future.

Acknowledgement A machine generated summary based on the work of Wong, Ho-Tin; Khalil, Modar; Ahmed, Fayyaz. 2020 in The Journal of Headache and Pain.

The Use of Behavioral Modalities for Headache During Pregnancy and Breastfeeding