Extensive pregnancy-related off-treatment time in women with familial hypercholesterolaemia

• Most lipid-lowering therapies are contraindicated from preconception to end of breastfeeding • Duration of pregnancy-related off-treatment time varied largely, from 0.8 to 12 years. • Late diagnosis and long pregnancy-related off-treatment time led to untreated for most of life. • Early diagnosis and treatment are essential to compensate for later off-treatment time. • More research on potential effects of statins during pregnancy and breastfeeding is needed. Most lipid-lowering therapies are contraindicated from preconception to end of breastfeeding Duration of pregnancy-related off-treatment time varied largely, from 0.8 to 12 years. Late diagnosis and long pregnancy-related off-treatment time led to untreated for most of life. Early diagnosis and treatment are essential to compensate for later off-treatment time. More research on potential effects of statins during pregnancy and breastfeeding is needed. Women with familial hypercholesterolaemia (FH) lose substantial treatment time during their reproductive years as most lipid-lowering therapies are contraindicated from the preconception through the end of breastfeeding. We examined the duration of real-life pregnancy-related off-treatment time in 27 women with FH in Norway. Women with FH in Norway who had completed the ongoing FH-FEMINA study (ClinicalTrials.gov ID NCT05367310) were included. Women were followed from 36 th week of gestation and until one year after delivery or until end of breastfeeding. Information on use of medication before, during and after the current and previous pregnancies was collected. Pregnancy-related off-treatment time was calculated from discontinuation of lipid-lowering therapy when planning pregnancy, throughout pregnancy, and after delivery. The total duration of pregnancy-related off-treatment time after all childbirths (median 1, range 1-3) per woman was a median of 2.9 years (25 th -75 th percentile; 1.6-4.0), ranging from 0.8 to 12 years. The pregnancy itself accounted for median of 42.1% of the pregnancy-related off-treatment time, whereas the time before and after pregnancy accounted for a median of 57.9% (range 11.4% to 91.2%). When including untreated years in childhood and/or prior to diagnosis, the lifelong off-treatment time represented a median of 66.3% (range 41.9 to 100%) of lifetime without treatment. Early diagnosis and initiation of treatment is essential in girls with FH to compensate for pregnancy-related off-treatment time later in life. To minimize these pregnancy-related off-treatment periods, healthcare professionals should support women with FH to resume lipid-lowering therapy immediately after breastfeeding and between pregnancies. In addition, more knowledge on the potential effects of statin use during pregnancy and breastfeeding on maternal and offspring health is urgently needed.