September 24, 2003
Multiple Sclerosis Society
Pregnancy is known to have an effect on MS. The summary below brings together some of the key issues around pregnancy in people with MS.
It is widely reported that most pregnant women with MS experience a decrease in relapses in the last third of pregnancy and an increase in the three months following birth. However, the overall relapse rate is no different to non-pregnant women with MS and there are no reported effects of pregnancy on the long-term course of the disease.
There is no effect of MS on fertility, although sexual dysfunction, which is estimated to affect 50-90% of people with MS, may affect the ability to conceive - referrals to specialists are advised. Oral contraceptives do not adversely affect MS and are often prescribed, although some drugs used to treat MS may reduce their effectiveness. However, if there is immobility the risk of thrombosis can increase.
There is no increased risk of miscarriage, stillbirth frequency, birth defects or infant death associated with MS. Consequently there is no need for high-risk pregnancy management although there may be a need for assisted delivery due to increased fatigue during labour. Women with MS who become pregnant may find, however, that this aggravates pre-existing bladder or bowel problems. Epidurals and local or general anaesthetics have been shown to not influence relapse rates and decisions to use them should be based solely on birthing needs.
Therapy use during pregnancy
Many of the therapies used in MS are not adequately studied in humans and therefore their effects on pregnancy are not known. It is acknowledged to be for the individual to decide whether the benefits of taking the drug outweigh any risks to the foetus, or not. However, if possible stopping treatment three months prior to conception is advised, although there is currently no definitive evidence on this. The effects of breast-feeding while taking therapies are not currently known. Similarly, there is no scientifically based data on when or if disease modifying therapies should be started/restarted after delivery.
The long term monitoring of pregnant women with MS has suggested that
decisions regarding pregnancy should be based on the level of disability
and disease course. The authors of this article report that the risk of
a child, developing MS, with one parent with MS is 3-5%, compared with
0.2% for the general Caucasian population. This is reported as exceeding
30%, if both parents have MS. (Personal correspondence with Prof. Alastair
Compston, from Cambridge University, has reported the risks for a child
with one parent with MS developing the condition is 2%, and the risk between
20-30% where both parents are affected.)
The impact of living with MS, especially if the disease is in the progressive phase can affect parent/child relationships. The authors highlight that although families face uncertainty over time, clinics, specialists and societies have excellent resources to assist families affected by MS, and that research is ongoing in this important area.
This report was published in The International MS Journal, June 2003, vol. 10, pages 44-59 and 67.
Hormone Therapy for MS
Pregnancy, particularly the last three months, is known to have a protective effect on MS. It is thought that these protective effects are anti-inflammatory, since pregnancy also (temporarily) reduces relapse rates. This is caused by a general dampening of immune responses to prevent the mother's body rejecting the baby, as it has material which is ?foreign? to the mother, through being inherited from the father.
High doses of oestradiol (a form of the hormone oestrogen) are protective in animal models of MS. It is not known whether oestrogen levels lower than those occurring in pregnancy, but higher than normal, such as those induced by oral contraceptives or hormone replacement therapy, are high enough to be protective in MS. However, a large study found incidence rates of MS were not decreased in pill users, compared to those who had never taken oral contraceptives. This suggests that oestrogen in oral contraceptives is not the correct type, or a high enough dose, to reduce the risk of MS.
Based on the protective effect of pregnancy, there has been an initial 6-month clinical trial of oral oestrogen (using similar levels of oestrogen to that seen in pregnancy) to try and mimic the protective effect of pregnancy on MS. Six people with relapsing remitting MS and four people with secondary progressive MS finished the trial. Side effects were minimal, with only menstrual cycle abnormalities reported. MRI (brain scanning) showed a significant reduction in active lesions (areas of damage) during treatment, compared to non-treatment, in people with relapsing remitting MS only. This did, however, return to the levels seen before treatment, once treatment was stopped. There was no effect on secondary progressive MS.
Oestrogen based treatments are appealing for the treatment of MS as information on their general safety and tolerability is already known and they can be taken orally. They appear to be potentially promising in treating RRMS, although there is very little data on this. One possibility is to combine them with the disease modifying drugs, to maximise the reduction in the immune response and hopefully combine the effects. Pilot trials of these combinations are planed.
This report was published in The International MS Journal, June
2003, vol. 10, pages 60-66.
Copyright © 2003, Multiple Sclerosis Society