Safety of vitamin D treatment doses in pregnancy
Routine supplementation of vitamin D at doses of 400units (10micrograms) per day is currently recommended for pregnant women. Higher doses of vitamin D for treating deficiency may be considered in a pregnant woman if local laboratory results indicate a need for treatment.
Prescribers should always refer to general guidance before prescribing in pregnancy.
UKTIS provide detailed information on the safety of Vitamin D in pregnancy for healthcare professionals (registration required).
The UKTIS has also produced a patient friendly factsheet (freely available) to inform expectant mothers about the safety of taking vitamin D during pregnancy.
Consult local guidance in the first instance.
The optimal dose to correct vitamin D deficiency safely in pregnancy is still not clear from the available data and evidence.
For oral treatment of vitamin D deficiency in pregnant women, the Royal College of Obstetricians and Gynaecologists (RCOG) suggest colecalciferol 2,800units daily, colecalciferol 20,000units weekly, or ergocalciferol 10,000units twice a week should be used for 4-6 weeks.
Other international guidance recommends a daily intake of 1,000-2,000units, with upper limits of 4,000units daily advised in the American College of Obstetricians and Gynaecologists (ACOG) guidelines.
In certain situations higher doses may be used or recommended by specialists.
Very high single bolus doses of intramuscular vitamin D (300,000-500,000 units) would only ever be considered in specialist settings and are not generally recommended in pregnant women.
Monitoring following treatment of vitamin D deficiency
The decision to treat vitamin D deficiency should be based on local laboratory findings and be guided by local vitamin D reference ranges.
The RCOG make no recommendations in their guidance around monitoring of serum calcium or vitamin D levels following treatment with vitamin D in pregnancy.
Once treatment is started, vitamin D levels are not routinely checked, but can be checked around 3-6 months after treatment when steady state levels are likely to have been attained.
For pregnant women being treated for vitamin D deficiency, it may be prudent to check maternal calcium levels within a month of completing the regimen as is suggested for the general population. It also seems reasonable to check calcium levels again three months later, when steady state vitamin D levels have been achieved.
It may be reasonable to check neonatal calcium and vitamin D levels at delivery if there are concerns about these.
Preferred forms of vitamin D used for treating vitamin D deficiency
The Electronic Medicines Compendium (eMC) provides a list of UK products and prescribing information, including vitamin D products that are licensed for treatment of vitamin D deficiency during pregnancy. Note that some manufacturers of colecalciferol preparations state they can be taken during pregnancy when strictly indicated to correct vitamin D deficiency.
Combined calcium and vitamin D products are not routinely used to correct vitamin D deficiency in pregnancy but may have a role in women at high risk of pre-eclampsia.