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Pregnancy Associated Osteoporosis (PAO)

By Karen Whitehead MBE (PAO Mum & PAO Patient Group Co-ordinator) and Kathryn Berg (University of Edinburgh)

Pregnancy Associated Osteoporosis is a severe and rare form of osteoporosis, affecting women who are pregnant or postpartum.  “Red flags” for midwives and maternity healthcare professionals are mothers complaining of extreme pain in the spine and hips, and loss of height.

“Claire” presents to the labour ward aged 32, having had an otherwise normal pregnancy. She is given an epidural and later that evening her midwife tells her she needs to push harder. She pushes as hard as she can. Despite the numbness in the lower half of her body, she feels a pop. Then another, and another. She doesn’t know it but she has just fractured four of her vertebrae. In fact, she doesn’t find this out for another six months.

Claire is one of a handful of women in the UK who have been diagnosed with pregnancy-associated osteoporosis, or PAO. Despite visiting her GP several times for the pain in her spine in the weeks and months following the birth of her child, she was denied a referral to the hospital for imaging and was refused painkillers, misinformed that it wasn’t safe for her to take analgesics while breastfeeding.

Several months go by and she feels her back “pop” on several occasions. These are low trauma incidents like picking her baby up or simply turning over in bed. At this point she can no longer walk, drive, or lift her own child. At one point she visits the GP and her height is measured in the clinic, “5’2”” the nurse tells her. “I’m 5’4””, she responds. “You’re 5’2””. Once again, she is sent home.

Six months after giving birth, Claire goes to A&E with extreme pain in her spine. She is given an x-ray but the doctor on call tells her that it has come back normal and that her pain must be muscular. On the following Friday she receives a phone call, asking her to come in to the local practice.

The radiology report has come through, and she has eight broken bones in her back.

Sadly, this is an all too familiar tale when speaking to women who have been diagnosed with pregnancy-associated osteoporosis. They are told that it is normal to have a sore back after giving birth, or that they simply have a low pain tolerance. In some of the worst cases they are accused of drug seeking, or of neglecting their newborn babies.

During pregnancy, intestinal calcium absorption doubles to meet fetal demand. Where calcium intake isn’t sufficient to meet the demand of both mother and baby, the maternal skeleton will undergo increased resorption in the third trimester. During lactation, hormonal changes invoke a loss of mineral from the skeleton in order to provide calcium to the milk, working out to approximately 210mg of calcium being passed to the newborn child daily. After reproduction and weaning the maternal skeleton usually returns to normal mineral content and strength, and fractures do not normally occur.

Women who present with vertebral fractures during pregnancy may have a low dietary calcium intake or a lactose intolerance, although low dietary calcium is not thought to be involved in the mineral loss experienced during lactation. Women with a diagnosis of PAO are also more likely to have a family history of osteoporosis, which may suggest a predisposition to lower bone density.

The frequency with which pregnancy and lactation associated fractures occur in the general population is unclear and possibly under-reported, but diagnosis is very rare, reported in approximately 4 in a million pregnancies. Though bone mass tends to recover in the months and years following the diagnosis, quality of life remains poor long beyond the point of skeletal recovery. Women diagnosed with the disorder report that they are told that they will have a “spontaneous recovery” of the skeleton, with little attention given to the trauma of the diagnosis or to the physical effects on their bodies.

There are three main modes of presentation of PAO, vertebral fractures during pregnancy, further low-trauma fractures while breastfeeding, and transient osteoporosis of the hip. It is particularly important not to ignore any loss of height during pregnancy or in the post-partum period, particularly if the patient complains of severe back or hip pain. Women who present with vertebral fractures commonly have normal blood work and it is difficult to assess prenatal bone density as this patient group has rarely had this assessed previously.

In many cases, vertebral and other skeletal fractures go undiagnosed for several months because of a propensity for doctors and healthcare professionals to attribute back and hip pain to the normal aches of pregnancy and birth.

It is important this disease is diagnosed quickly to avoid further harm to both mother and child.   PAO mothers have reported dropping their babies when their spine breaks trying to pick them up, often attempting to this under pressure from health care professionals. Fractures can present in any point in pregnancy or postpartum period, but are most common in the last trimester, during childbirth or in the first 12 weeks postpartum.

Diagnosis is usually made through the discovery of fractures, which is confirmed by an x-ray or MRI scan.  A Dexa scan may then show that bones are in the osteopenic or osteoporotic bone range.

Causes of the disease are not fully understood yet and there is currently new groundbreaking UK research https://www.ed.ac.uk/centre-genomic-medicine/research-groups/ralston-group/pao-study

We ask all those involved in maternity and midwifery to encourage mothers to get involved in this new research, whether diagnosed as PAO cases, or undiagnosed, to act as controls. This is a devastating and unknown pregnancy-associated disease and we would urge all mothers to help us find the answers.

 

Further information:

 

  • Research Papers:
    • Pregnancy and Lactation Associated Osteoporosis, Sarah A. Hardcastle, Calcified Tissue International 2022, 110:531-545, https://doi.org.10.1007/s00223-021-00815-6
    • The experience of pregnancy associated osteoporosis: An international survey with implications for Midwifery Care, S.B.Condon, M, Veitch, Midwifery, 2022, 115: 103468
    • Women with pregnancy & lactation associated osteoporosis (PLO) have low bone remodelling, Cohen, M, Kamanda-Kosseh, D>W. Dempster, D, et. al. J Bone Miner. Res., 34, 2019, 34 (9) 1552-1561 https://asbmr.onlinelibrary.wiley.com/doi/full/10.1002/jbmr.3750
    • Associations of parity, breastfeeding and fractures in the Women’s Health Observational Study, Crandall, C.J., Liu, J., Cauley, J. et. al. 2017 Obstrer.Gynecol. 130 (1), 171.
    • Comparison of efficacy of pharmalogic treatments in pregnancy and lactation associated osteoporosis, Hong, N., Rhee, Y. 2019 Clin. Rev. Bone Research Miner.Metab, 17 2), 86-93
    • Long-term outcome of patients with Patients with pregnancy and lactation associated osteoporosis (PLO) with a particular focus on quality of life, Gehlen, M., Lazarescu, A.D, Hinz, C. et. al. 2019 Clin.Rheumatol. 38 (12), 3575-3583
    • Effect of Teriparatide on Bone Remodeling and Density in Premenopausal Idiopathic Osteoporosis: A Phase II Trial, 2020, Cohen, A. et. al. Published by Oxford University Press on behalf of the Endocrine Society 2020 ISSN online 1945-7197 ISSN Print 0021-972X
    • Subsequent fracture risk of women with pregnancy and lactation-associated osteoporosis after a median of 6 years of follow-up, Kybernitakis, I., Hadji, P., et. al, 2018, Osteoporos Int. 29@ 135-142
    • Pregnancy-associated osteoporosis: Does the skeleton recover? Phillips, A.J., Ostlere, S.J., & Smith, R. 2000. Osteoporosis International 11: 449-454
    • Presentation and management of osteoporosis presenting in association with pregnancy or lactation, Kovacs, C.S. Ralston, S.R. 2015, Osteoporos Int, DOI 10.1007/s00198-015-3149-3
    • The skeleton is a Storehouse of Mineral that is Plundered during Lactation and (Fully?) Replenished Afterwards, Kovacs, C.S. Journal of Bone and Mineral Research, JBMR, 2017, Vol. 32, No. 4: 676-680
    • Pregnancy-associated osteoporosis: a case-control study, Hadji, P. et. al, Osteoporos Int (2017) 28: 1393-1399
    • Risk Factors, fractures and management of pregnancy-associated osteoporosis: a retrospective study of 14 Turkish patients, Gynecol Endocrinol. 202 March; 36 (3) : 238-242
    • Pregnancy-related fractures: a retrospective study of a French cohort of 52 patients and review of the literature, Laroche, M. et. al. 2017, Osteoporos Int. 2017, Nov 28 (11): 3135-3142
    • Pregnancy and lactation associated osteoporosis with vertebral fractures: a systematic review, Ying Qian, et. al, 2021, BMC Musculoskelet Disord 2021; 22: 926
    • Relevant genetic variants are common in women with pregnancy and lactation-associated osteoporosis (PLO) and predispose to more severe clinical manifestations, Butscheidt, S. et al, Bone, 2021 June: 147: 115911 PMID 33716164, DOI: 10.1016/j.bone.2021.115911
    • Effect of Teriparatide on Subsequent Fracture and Bone Mineral Density in 47 women with Pregnancy and Lactation-Associated Osteoporosis & Vertebral Fractures. Hadji,P. 2022 https://www.thieme-connect.com/products/ejournals/pdf/10.1055/a-1816-6700.pdf
    • Bone Turnover in pregnancy, measured by urinary CTX, is influenced by Vitamin D Supplementation and is associated with maternal bone health Osteoporosis Study (MAVIDOS) trial, Curtis, E. et al. The American Journal of Clinical Nutrition, November 2021, Vol 114, Issue 5: 1600-1611
    • Femoral Analysis, Mechanical Testing and Innumolocalization of Bone Proteins in a Model of Pregnancy and Lactation-Associated Osteoporosis, Tomaszewska, E. et al, J. Clin. Med 2021, 10(21), 4808 https://www.mdpi.com/2077-0383/10/21/4808
    • Effect of Teriparatide on Bone Remodelling and Density in Premenopausal Idiopathic Osteoporosis: a Phase II Trial, Cohen, A. et al, The Journal of Clinical Endocrinology and Metabolism, Volume 105, Issue 10, October 2020, pages e3540-3556 https://academic.oup.com/jcem/article/105/10/e3540/5900497
    • Review of Current Real-World Experience with Teriparatide as Treatment of Osteoporosis in Different Patient Groups, Hauser, B. etc. at. J. Clin. Med, 2021, 10 (7), 1403 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8037129/
    • Denusomab after Teriparatide in Premenopausal Women with Idiopathic Osteoporosis, Shane, E. Cohen, A. et al, The Journal of Clinical Endocrinology & Metabolism, April 2022, Volume 107, Issue 4, Pages e1528-1540 https://academic.oup.com/jcem/article/107/4/e1528/6437931?login=false
    • Bridging the Gap: Pregnancy – and Lactation – Associated Osteoporosis, Carsote M. et al, MDPI Special Issue Endocrine Disorders – from Evidence-based Medicine toward Individual Management, 3 May 2023, Diagnostics 2023, 13 (9), 1615, https://www.mdpi.com/2075-4418/13/9/1615
    • Pregnancy and Lactation-Associated Osteoporosis Successfully Treated with Romosozumab: A Case Report, Kaneuchi, Y et al., Medicina (Kaunas) 2023, Jan, 59(1): 19, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9862917/
    • Also:

The following NICE Guidelines may be relevant to the clinical care of PAO patients, but this list is not exclusive and other Guidelines may also apply:

Pregnancy Associated Osteoporosis is a severe and rare form of osteoporosis, affecting women who are pregnant or postpartum.  “Red flags” for midwives and maternity healthcare professionals are mothers complaining of extreme pain in the spine and hips, and loss of height.  

Causes of the disease are not fully understood yet and there is currently new groundbreaking UK research https://www.ed.ac.uk/centre-genomic-medicine/research-groups/ralston-group/pao-study

We ask all those involved in maternity and midwifery to encourage mothers to get involved in this new research, whether diagnosed as PAO cases, or undiagnosed, to act as controls. This is a devastating and unknown pregnancy-associated disease and we would urge all mothers to help us find the answers. 

 

Karen Whitehead MBE (PAO Mum & PAO Patient Group Co-ordinator) and Kathryn Berg (University of Edinburgh)

Email: [email protected] and [email protected]

Kathryn Berg, Trial Manager, The University of Edinburgh

Email: [email protected]

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