Less Sleep During and After Pregnancy May Spell Future Heart Troubles

Persistently short sleep duration during and after pregnancy was tied to a greater risk for adverse cardiometabolic outcomes, a secondary analysis of cohort study data showed.

Women who said they slept fewer than 7 hours a night during and after pregnancy had higher odds of new-onset metabolic syndrome (adjusted odds ratio [OR] 1.60, 95% CI 1.21-2.11) — the combination of hypertension, insulin resistance, obesity, and dyslipidemia, Minjee Kim, MD, of the Feinberg School of Medicine at Northwestern University in Chicago, and colleagues reported.

Persistent short sleep, however, was not tied to an increased risk of incident hypertension alone (adjusted OR 0.91, 95% CI 0.69-1.19), the researchers wrote in JAMA Network Open.

Women who persistently slept even less — under 6 hours per night — carried a higher risk for developing metabolic syndrome than those who never had short sleep (adjusted OR 2.31, 95% CI 1.36-3.93).

“The fact that sleep patterns over a relatively short period could have a significant impact on long-term cardiometabolic health highlights the urgency of addressing sleep health during this critical life stage,” Kim told MedPage Today.

Prior research has tied short sleep during pregnancy to hyperglycemia and gestational diabetes. Persistent short sleep across midlife has also been linked with cardiovascular disease in women.

“[T]here is a need to identify and target modifiable risk factors associated with metabolic syndrome in this population to reduce the burden of cardiovascular disease, the leading cause of mortality in U.S. women,” Kim and colleagues underscored. “The prevalence of metabolic syndrome has been increasing in the U.S., especially in women aged 20 to 39 years.”

This study was a secondary analysis of data from two cohort studies: the Nulliparous Pregnancy Outcomes Study Monitoring Mothers-to-Be (NuMoM2b) conducted between September 2023 and March 2024, and the ongoing NuMoM2b-Heart Health Study.

The final cohort included 3,922 women with sleep duration data 2 to 7 years after the index pregnancy. Average baseline age was 27.3 years; 15.2% were Hispanic, 12.4% were Black, and 64.8% were white. Also, 64.3% were married at baseline.

Women fasted for 8 hours prior to follow-up visits. Biological specimens and anthropometric measurements were collected, and blood pressure was measured three times. Sleep patterns were self-reported.

Metabolic syndrome was defined as the presence of at least three of the following five criteria:

• Waist circumference 80 cm or more among Asian participants, or 88 cm or more among other participants
• Triglyceride levels ≥150 mg/dL or use of a triglyceride-lowering medication
• Fasting glucose levels ≥100 mg/dL or use of a glucose-lowering medication
• Systolic blood pressure ≥130 mmHg, diastolic blood pressure ≥85 mmHg, or use of antihypertensive medication
• High-density lipoprotein levels

During pregnancy, 25.8% of participants said they slept less than 7 hours, which increased to 38.2% at a mean follow-up of 3.1 years.

Unmarried women were significantly more likely to experience persistent short sleep than married women (adjusted OR 1.68, 95% CI 1.29-2.19). Also, Black women were significantly more likely to experience persistent short sleep than white women (adjusted OR 2.17, 95% CI 1.59-2.97).

“Due to structural factors, historically marginalized groups and those with fewer resources may be at especially high risk of inadequate sleep duration in the years after childbirth, which may influence their long-term health patterns,” the researchers pointed out.

Kim added that this “highlights the need to address structural and environmental factors contributing to these disparities and their potential health impacts.”

In a sensitivity analysis that defined short sleep duration as less than 6 hours, persistent short sleepers (during and after pregnancy), new short sleepers (only after pregnancy), or those with resolved short sleep (only during pregnancy) all had higher odds of developing metabolic syndrome compared with women who never slept less than 6 hours:

• Persistent: adjusted OR 2.31 (95% CI 1.36-3.93)
• New: adjusted OR 2.12 (95% CI 1.55-2.91)
• Resolved: adjusted OR 1.73 (95% CI 1.16-2.57)

“These findings highlight the need for targeted interventions aimed at improving sleep health among populations at increased risk to mitigate adverse health outcomes and to promote health equity,” Kim’s group said.

Kim suggested that future studies “should prioritize identifying modifiable factors and developing practical, scalable interventions to promote sleep health, particularly for individuals who are more vulnerable to undesirable sleep patterns.”

Study limitations included self-reported sleep information. Also, there was a lack of comprehensive data on other important sleep characteristics like sleep regularity and satisfaction.