Given the increasing number of disease modifying therapies for MS in Australia it is more critical than ever that neurologists are able to counsel their patients on family planning, experts say.
In a review published in the MJA, Anneke Van Der Walt from Monash University and colleagues noted that studies assessing the impact of disease modifying therapies (DMTs) on pregnancy were limited and tend to be hampered by small sample size.
“While avoiding any potential drug exposure risks to the fetus seems prudent, discontinuation of treatment preconception is also associated with an increased risk of the reappearance of disease activity, especially if there are significant delays in conceiving,” they wrote.
It was therefore vital that all women with MS who were considering starting a family had a treatment plan that covered pre-pregnancy, pregnancy and the post-partum period, particularly as discussions held prior to contraception could influence the initial choice of DMT.
While evidence showed that most women with MS experience ‘normal’ pregnancies, women with unplanned pregnancy while taking DMTs may have concerns around the potential teratogenic effects of the therapy, the review authors noted.
The timing of exposure to a potential teratogen was critical, with the first eight weeks post-conception being the most vulnerable time point.
They noted that in recent years, discussion around the safety of treatment during pregnancy had become more nuanced, “with the recognition that decreasing the risk to the fetus by minimising drug exposure must be balanced against the risk of increased disease activity in the mother”.
Glatiramer acetate, dimethyl fumarate, alemtuzumab and daclizumab (withdrawn in 2018 due to other safety concerns) presented the least risk of malformations or irreversible damage to the fetus in pregnancy, with the TGA giving all four a Category B pregnancy rating.
“Understanding these classifications better may assist physicians in performing a more accurate risk–benefit assessment of the multiple sclerosis DMT-related risks, while recognising that the background population risk for any major malformation (without taking into account confounders such as maternal age) is 3–5%,” the review authors said.
International pregnancy registries had a key role to play in further elucidating the risks and benefits of DMTs during pregnancy and neurologists should be encouraged to contribute to these when possible, they advised.
According to the authors, a multidisciplinary approach involving neurologists, obstetricians, midwives, anaesthesiologists and fertility specialists was the best way to optimise outcomes for the patient and their child.
“Decision making should be a shared experience between patient and physician, with a personalised approach developed to meet the unique needs of each individual patient,” they added.