Pregnancy

There is evidence of symptom improvement or remission in many inflammatory and autoimmune diseases during pregnancy. This may be due to hormonal or immune changes.

Immune changes during pregnancy
The mucosal immune system undergoes profound changes so that the mother's body won't reject the fetus. Tregs increase. TGF-beta increases. Progesterone and estrogen, which both have anti-inflammatory properties, increase. The immune skews to a Th2 response.

Fertility
Women with CFS report higher rates of polycystic ovarian syndrome (PCOS) and anovulatory cycles, higher rates of dysmenorrhea and higher rates of endometriosis.

Symptoms during pregnancy
There has been very little research on pregnancy and ME or CFS. One retrospective survey found that 41% of respondents reported no change in symptoms during pregnancy, 30% improved and 39% got worse.

In clinical practice, Dr. Nancy Klimas, Dr. Lucinda Bateman, and Dr. Charles Lapp report higher rates of improvement or remission during pregnancy. Klimas reports that in the 20 women she has followed through pregnancy, improvement in symptoms during pregnancy was "almost universal" and in some cases resulted in total temporary remission. Dr. Lapp reported that 25 out of 27 patients in his practice felt better during pregnancy. Dr. Klimas suggests that improvement may be due to increased blood volume during pregnancy or hormonal changes.

Postpartum
In one survey, after delivery, 30% had no change in symptoms, 20% improved, and 20% got worse. Dr. Klimas reports that her patients typically do well postpartum until about 3 to 6 months after at which time there is often a severe relapse.

Complications
When comparing these women's pregnancies after illness onset to pregnancy before illness onset (but not to healthy controls), the rate of complications were similar but in pregnancies occurring after illness onset, there was a higher rate of miscarriages (30% v. 8%) and development delays or learning disabilities (21% v. 8%). However, this may have been due in whole are part to maternal age (pregnancies before illness onset occurred when women were younger than pregnancies occurring after illness onset).

Pregnancy in other conditions
In general, Th1 dominant immune disorders tend to improve during pregnancy while Th2 dominant immune disorders tend to worsen. For example, in a study of women with rheumatoid arthritis 75% of patients experienced remission of their RA during pregnancy and 62% experienced a worsening of symptoms after delivery. 92% relapse within the first three months after delivery. The course of Crohn's disease and ulcerative colitis improves during and after pregnancy. In relapsing-remitting multiple sclerosis, rates of relapse decrease during the first two trimesters and increase significantly postpartum.

By contrast, pregnancy increases rates of lupus flares. In a retrospective study of fibromyalgia patients based on personal interviews, nearly all patients surveyed experienced a worsening of symptoms during pregnancy, especially during the third trimester. Fibromyalgia did not appear to have an adverse effect on the outcome of pregnancy or the health of the baby.