MS not behind higher early C-section rates in patients, study says

Medically indicated cesarean sections (C-sections) before 39 weeks of gestation, or full term pregnancy, may be more frequent among women with multiple sclerosis (MS) than in those without the disease, a study found.

However, this difference was not linked to MS itself, with most commonly reported reasons for early C-section being standard obstetric indications, including stalled labor.

No significant differences in terms of rates of nonmedically indicated C-sections before 39 weeks and newborn outcomes were found between pregnant women with and without MS. Still, MS was frequently documented as a pregnancy complication or reason for referral to a high-risk pregnancy specialist.

“Our findings are reassuring for women with MS planning pregnancies,” researchers wrote, adding, however, that documenting MS as a pregnancy complication “suggests persistent provider misconceptions” about the risks associated with the disease during pregnancy.

The study, “Cesarean sections prior to 39 weeks among pregnant patients with multiple sclerosis,” was published in Multiple Sclerosis Journal.

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Pregnancy was once considered high risk for women with MS due to reports of severe relapses and other complications. Currently, it is considered generally safe without increased health risks to the mother or fetus.

However, previous research shows that women with MS are much more likely to undergo C-sections than those without the disease. It is less clear whether these C-sections are performed before 39 weeks of pregnancy, when they are generally not recommended due to the risk of adverse outcomes for newborns unless medically necessary.

To learn more, a team of researchers in the U.S. retrospectively analyzed electronic health records of women receiving prenatal care at Kaiser Permanente Southern California, a prepaid healthcare delivery system, between 2009 and 2024.

They identified 600 pregnancies in 662 women with MS and 1,199 in 1,323 women without the disease who served as controls and were matched for some factors, including year of delivery, maternal age, and race/ethnicity.

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Early C-sections significantly more common in women with MS

Early C-sections (before 39 weeks) were significantly more common in women with the disease than in those without (15.2% vs. 9.8%), particularly when medically indicated (11.5% vs. 6.9%). Nonmedically indicated C-sections were less common and comparable between the MS and control groups (3.7% vs. 2.8%).

Nearly half (48.7%) of medically indicated early C-sections had more than one reason. The most common indications were similar among women with MS and those without, including abnormal fetal position for delivery, fetal distress, and preeclampsia, a pregnancy complication marked by high blood pressure and signs of organ damage.

A significantly higher proportion of medically indicated early C-sections among women with MS was due to previous surgery to remove benign growths of tissue deep inside the uterus muscle wall, which can weaken the uterus wall (1.7% vs. 0.3% for controls), and stalled labor, when the natural process of childbirth stops (2.7% vs. 0.8%).

A review of 15 MS pregnancies with detailed information on stalled labor found no association with MS-related fatigue, impaired maternal pushing, or neurological disability.

Among nonmedically indicated early C-sections, the most common reasons were nonurgent medical reasons (elective delivery), patient preference, and/or repeat C-section without attempting vaginal delivery. MS itself was cited as the reason in only two cases.

Women with MS and those without the disease who underwent early C-section had comparable age, race or ethnicity, and number of previous pregnancies. Also, more than 73% of women in both groups had at least one other health condition at the time of conception.

Future studies to assess how provider perceptions of MS and counseling practices influence maternal mental health are needed as are intervention studies to correct the misperception that MS is a high-risk pregnancy condition.

However, women with MS were significantly more likely to have a mental health condition at the start of pregnancy (27.5% vs. 2.8%) but significantly less likely to have diabetes (6.5% vs. 16%) than those without MS.

MS-related disability was generally mild among women with MS who had C-sections before 39 weeks. About one in five of these pregnancies (23.1%) involved exposure to disease-modifying therapies (DMTs), mostly during the first three months of pregnancy. DMT exposure was not associated with differences in C-section indications or newborn outcomes.

Because the study was not designed to assess the safety of DMTs during pregnancy, “these findings should be interpreted cautiously,” the team wrote.

Still, MS was explicitly reported as a pregnancy complication in 24.2% of pregnancies ending in early C-sections and was listed as a reason for referral to a high-risk pregnancy specialist in more than one-third (35.2%) of these pregnancies. According to the team, these findings suggest “there may still be lingering misconceptions about MS as an inherent [pregnancy] risk.”

Newborn outcomes associated with early C-sections were broadly similar between the MS and control groups, with comparable median gestational age at birth and birth weight. Three stillbirths occurred among pregnancies with MS, and none of the women had significant MS symptoms or were on DMTs.

“Future studies to assess how provider perceptions of MS and counseling practices influence maternal mental health are needed as are intervention studies to correct the misperception that MS is a high-risk pregnancy condition,” the researchers wrote.