Pregnancy and lactation-associated osteoporosis incidence higher than previously reported

Key takeaways:

• Estimated pregnancy and lactation-associated osteoporosis incidence was 460 per 1 million deliveries.
• Vertebral fracture was the most common type of pregnancy and lactation-associated premenopausal osteoporosis.

Pregnancy and lactation-associated osteoporosis incidence was greater than previously reported, suggesting potentially overlooked patients, with vertebral fracture the most common type of premenopausal osteoporosis, researchers reported.

“Pregnancy and lactation-associated osteoporosis is such a rare and easily overlooked condition that its investigation requires well-designed large-scale studies,” Kyoto Kasahara, MD, from the department of obstetrics and gynecology at Shiga University of Medical Science, Japan, and colleagues wrote in BMC Pregnancy and Childbirth. “In addition, to date, no screening, diagnosis or management strategies for pregnancy and lactation-associated osteoporosis have been firmly established.”

Kasahara and colleagues conducted a retrospective cohort study using the Japan Medical Data Center administrative claims database to identify 105,931 insured women with data on childbirth date from January 2005 to September 2017. Women with low-trauma factors aged 18 to 47 years were categorized as the premenopausal osteoporosis group. Researchers considered a fracture site for which the OR for fractures occurring 5 months before to 12 months after childbirth was greater than 1 as the pregnancy and lactation-associated osteoporosis (PLO) site. Women with fractures at the PLO site were classified as the PLO group. Researchers compared women with fragility fractures with 500 women without fracture.

Overall, 231 women with 237 fractures were in the premenopausal osteoporosis group, of which 74 fractures occurred around childbirth. Fifty-six women with 57 fractures were in the PLO group.

The most common fracture in the premenopausal osteoporosis group was vertebral fracture (35%), followed by distal radius (28.7%) and sacral (21.1%) fractures. Vertebral fracture was also the most common fracture in the PLO group (78.9%), followed by pelvic (17.5%) and proximal femoral (3.5%) fractures. Vertebral fracture was likely to occur around childbirth, whereas distal radius and sacral fractures were not.

Vertebral fracture was commonly diagnosed a few months to up to 1 year postpartum. Researchers estimated PLO incidence as 460 per 1 million deliveries, which was greater than previously reported incidences of four to eight per 1 million pregnancies.

Compared with the control group, women in the PLO group had older maternal age (P = .0082). In addition, “absent, scanty and rare menstruation” (OR = 3.8; 95% CI, 1.38-10.5), “female infertility associated with anovulation” (OR = 2.1; 95% CI, 1.12-3.92) and “female infertility unspecified” (OR = 2.02; 95% CI, 1.11-3.68) were more frequent among women in the PLO vs. control group.

In the PLO group, women with vertebral fractures had more medical interventions, with the highest frequency of intervention occurring 1 to 6 months postpartum. Twenty of the 45 women with vertebral fractures were given anti-osteoporosis pharmacotherapies. The most frequent anti-osteoporosis pharmacotherapies given were active vitamin D analogs, followed by bisphosphonates and calcium.

“More attention to and appropriate medical interventions for all types of fragility fractures in young women are recommended to help reduce the risk of fracture in the future,” the researchers wrote. “In addition, more timely interventions for PLO might lead to the improved management of latent patients with premenopausal osteoporosis."