Bone Density Changes During Pregnancy and Breastfeeding
Pregnancy and breastfeeding place unique demands on a woman’s body. While these stages are often discussed in terms of pelvic floor recovery and sleep deprivation, bone health is less commonly addressed.
However, pregnancy and lactation can lead to temporary changes in bone density that are important to understand.
What happens to bones during pregnancy
During pregnancy, the body adapts to support the growing baby. Calcium is transferred to the baby to support bone development, particularly in the third trimester. To meet this demand, the body increases calcium absorption from food and, in some cases, draws on the mother’s bone stores (Kovacs, 2016).
For most women, this process does not cause long-term harm. However, it highlights how important nutrition and loading are during and after pregnancy.
Bone changes during breastfeeding
Breastfeeding leads to more noticeable changes in bone density. Oestrogen levels are low during lactation, which can result in bone loss of up to 5–10% at the spine and hip in the first six months (Kovacs & Ralston, 2015).
This bone loss is usually temporary. Bone density often recovers after weaning and the return of regular menstrual cycles. However, recovery is not automatic and varies between women.
Why some women are more affected
Factors that may affect bone recovery include:
- Prolonged breastfeeding
- Low body weight
- Inadequate calcium or vitamin D intake
- Limited weight-bearing or resistance exercise
- Closely spaced pregnancies
Women with a history of low bone density or eating disorders may be at higher risk of incomplete recovery.
The role of exercise in recovery
Bones respond to mechanical loading. Progressive resistance training and weight-bearing exercise help stimulate bone rebuilding after lactation (Howe et al., 2011).
Gentle movement alone is often not enough. Bones need progressive load to regain strength.
Why bone health is often overlooked
Postnatal care often focuses on the baby, with limited follow-up for the mother’s physical health beyond the early weeks. Many women are unaware that bone changes occur and may not return to strength training for months or years.
This delay can affect long-term bone health, particularly if further pregnancies follow.
The take-home message
Bone changes during pregnancy and breastfeeding are normal, but recovery requires support.
Returning to progressive strength and weight-bearing exercise after birth and lactation helps protect bone health for the future. Jessica Dingle our physiotherapist is extremely well placed to help women navigate this life stage, in a structured and staged manner.
References
Howe, T. E., et al. (2011). Exercise for preventing and treating osteoporosis. Cochrane Database of Systematic Reviews.
Kovacs, C. S. (2016). Maternal bone metabolism during pregnancy and lactation. Journal of Endocrinology, 231(2), R99–R115.
Kovacs, C. S., & Ralston, S. H. (2015). Bone metabolism during pregnancy and lactation. Endocrinology and Metabolism Clinics, 44(1), 57–69.