ABN 2025 Pregnancy Guidelines: What’s new?

Understanding of multiple sclerosis (MS) and pregnancy has evolved rapidly in recent years, with growing evidence helping to inform safer, more personalised care for women who wish to start or expand their families.

These developments are reflected in the updated guideline from the Association of British Neurologists (ABN), which is due to be published in the coming months.

In this webinar, clinicians explored how we can best support women with MS before, during, and after pregnancy, and in line with the updated guidelines.

Supporting women with MS through family planning and pregnancy

The updated ABN guidelines make specific reference to pre-pregnancy counselling. Dr Paarul Prinja, consultant acute and obstetric physician and honorary consultant obstetric physician at New Cross Hospital, Royal Wolverhampton NHS Trust and Birmingham Women’s Hospital, said this was very important.

She explained that MS does not directly affect fertility, and nor do fertility drugs affect MS. In addition, there MS does not increase the risk of prematurity, growth restriction, or adverse obstetric outcomes. Disease modifying therapies (DMTs) do not affect ovarian reserve or male fertility, though conception may be delayed by MS symptoms. “Sexual dysfunction needs to be addressed before anything else,” said Paarul, adding that it was crucial to have conversations about sex in clinic. “We do not want women and their families to have a delay to fertility services if conception does not occur within a year.”

Mental health is “incredibly important in pregnancy”, she went on. “Make every contact, pre-pregnancy, antenatally and postnatally, count, because, sadly, in the UK the leading cause of maternal mortality in the postnatal period in the UK remains suicide.” SSRIs, SNRIs, and TCAs are all safe to use in pregnancy, with no evidence of an association with miscarriage, pre-term delivery, or low birth weight.

Of course, women with MS may have comorbidities, and Paarul emphasised the importance of holistic care. “Women with MS may come in with joint pain or weakness and fatigue, and it will be all too easy to put it down to an MS flare… take a good examination, a good history, and make sure you are considering a wider differential. MS itself should not affect other comorbidities – but please don't forget about them,” she said.

In terms of how MS affects a pregnancy, most women find their symptoms settle. For some, however, it does bring an increased risk of urinary tract infections (UTIs), constipation, and gastroesophageal reflux. Other risks include back pain and symphysis pubis dysfunction, which can be significantly debilitating for women with MS. “It can lead to significant disability, which may well increase their risk of VTE,” said Paarul, adding that she would consider low molecular weight heparin prophylaxis when the risk is high. MS does not increase the risk of preeclampsia or obstetric haemorrhage.

Touching on analgesic medications, she highlighted that paracetamol was safe in pregnancy and during breastfeeding at an appropriate dose. If a woman is less than 50kg, she needs half the usual dose of two tablets four times a day, Paarul noted. Nonsteroidal anti-inflammatory drugs (NSAIDs) can be used until 28-weeks gestation, and in breastfeeding mothers. If opioids cannot be avoided, they should be used at the lowest possible dose for the shortest time due to the side effect profile. There is limited data on the safety of baclofen, pregabalin, and gabapentin during pregnancy, and so decisions should be based on a individual analysis of the risks and benefits. All are safe during breastfeeding. “Ideally, we like to have these conversations before pregnancy so we can outline a plan and share it with all healthcare teams, including primary care,” said Paarul.

Importantly, MS does not automatically make a pregnancy high risk, necessitate a caesarean section, call for extra scans or appointments, or mean a higher risk of obstetric complications. Such determinations are made based on the degree of physical debilitation and obstetric risk factors.

What is new in the ABN 2025 guidelines?

Dr Ger Mulla, internal medicine trainee and visiting scholar at Queen's University Belfast, went on to talk about the changes to be expected in the ABN guidelines, which were last updated in 2019. Since then, he pointed out, there have been advances in the data around therapeutic approaches in pregnancy, particularly around monoclonal antibodies and breastfeeding.

The updated guidelines were developed using a systemic literature review, focusing on the 2020-2025 period, and multidisciplinary team discussion and consensus. General themes include management at the preconception, pregnancy, and post-partum stages, as well as addressing unmet needs. “We are still not very good at identifying those who are at a high risk of relapse and we are not sure about the optimal approaches for postpartum management,” said Ger. “While data is improving, we still lack high-quality pregnancy data, particularly granular registry data.”

Reiterating Paarul’s point about MS not automatically deeming a pregnancy as high risk, Ger said personalised approaches to pregnancy planning should consider clinical history, likely MS disease activity during and after pregnancy, and the potential impact of treatment withdrawal. “We know that the harm from withdrawal is more significant with some treatments than others,” he said, adding that the discontinuation of immunosequestering DMTs, such as natalizumab and Sphingosine-1-phosphate (S1P) modulators, may result in the return or rebound of inflammatory disease activity during pregnancy.

Summarising the guidelines’ advice on specific DMTs, Ger said there was no evidence to suggest dimethyl fumarate exposure in early pregnancy leads to increased congenital malformation or miscarriage rates. “Women can keep taking dimethyl fumarate until pregnancy is confirmed. At that point we would usually recommend it be discontinued,” he went on, adding that the active metabolite is detectable only in small amounts in breast milk.

The advice on cladribine is to avoid pregnancy for six months after therapy in women, and three months for men. A full course in advance of conception can provide an administration-free pregnancy. To minimise foetal exposure, Ger went on, natalizumab should be given every six to eight weeks during pregnancy, with the last dose usually no later than 34 to 36 weeks gestation. To avoid rebound disease activity postpartum, it should be restarted within six to eight months of the last dose. Anti-CD20 treatment can continue until a positive pregnancy test, and restart a few days after post-partum, and women can breastfeed while on the therapy.

In terms of vaccines, the guidelines recommend all pregnant women with MS have the seasonal influenza and COVID vaccinations. In line with national guidance for all pregnant women, they should also receive the pertussis vaccination in the second trimester, and respiratory syncytial virus (RSV) in the third.

Magnetic resonance imaging (MRI) is not contraindicated at any time during pregnancy, but gadolinium contrast media should be avoided if possible. “If someone is stable during pregnancy, there's not necessarily a need for routine imaging,” said Ger. “In the postpartum period, if there is a therapeutic lag or disease activity is more likely to occur, you may wish to consider re-baseline imaging at that point.” There is no evidence, he went on, of risk to the baby from maternal contrast administration whilst breastfeeding.

The 2025 guideline also includes updated information on assisted reproduction technology. Recent large studies have shown it does not increase relapse risk, and DMTs can be continued as per the normal pregnancy guidance, Ger added. He went on to say that stem cell treatment can affect fertility, or in some cases, cause premature menopause. Both men and women undergoing the treatment, then, should be offered fertility preservation.

Supporting the pregnancy journey: In practice

Ideally, women with MS would have at least a year of stable disease before attempting to conceive, said Noreen Barker, consultant MS nurse at University College London Hospitals NHS Foundation Trust. “I think that really helps to calm their anxiety,” she said. However, other factors, including the person’s preference, their age, and any comorbidities, also need to be taken into account. Such conversations, Noreen added, should be part of pre-conception counselling, and shared decisions should be taken on an individual basis.

During pregnancy, she went on, there are key touchpoints for review. These include the first trimester, which is an opportunity to discuss treatments and risks, and provide general pregnancy advice that aligns with that of their obstetric team. The next is a second trimester review, then follow-up towards the end of the pregnancy. “Wants and needs during pregnancy are going to be a little bit different on a case-by-case basis. But certainly, when you're getting into that third trimester, you're thinking about the back to treatment plan, and making sure they know how to contact us,” Noreen explained, adding it was important “not to overload them with appointments”.