Vitamin B12 is, to put it simply, ‘essential for life’ (Kenny and Tidy, 2016). Vitamin B12 deficiency can result in symptoms of fatigue, poor memory, pins and needles, mental health issues, difficulty conceiving, mobility and balance problems, and a plethora of haematological and neuropsychiatric problems (Lindenbaum et al, 1988; Hector and Burton, 1988; Savage and Lindenbaum, 1995; Bennett, 2001; Pacholok and Stuart, 2011; Sahoo et al, 2011; National Institute for Health and Care Excellence (NICE), 2015a; NHS Choices, 2016; Singh, 2016).
Prevalence of vitamin B12 deficiency has proven difficult to ascertain owing to the poor quality of available data. In the UK, a conservative estimate equates to approximately 6% of people under the age of 60 years, and closer to 20% for those aged 60 years and over (Hunt et al, 2014). Although the data available are of limited quality, the World Health Organization (2016) acknowledges that vitamin B12 deficiency could be a serious public health problem, potentially affecting millions worldwide.
Folic acid supplementation is recommended during pre-conception and in early pregnancy to reduce the risk of the fetus developing a neural tube defect. Jaquier (2015) suggests that 0.4 mg of folic acid reduces the risk of neural tube defects by 50–70%. These are impressive statistics, and underline the importance of supplementation for improving outcomes. However, practitioners should be aware that supplementation of folic acid can mask a vitamin B12 deficiency (NHS Choices, 2016). As is the case with low folate, low vitamin B12 can also cause neural tube defects, alongside miscarriage and premature birth (Pacholok and Stuart, 2011). NHS Choices (2015) advises that GPs should assess serum vitamin B12 before supplementing with folic acid—an intervention that would clearly be of benefit to those considering pregnancy.
In infants and children, vitamin B12 deficiency may manifest as difficulty with feeding—most notably sucking and swallowing—and failure to thrive. Such symptoms may be mistaken for tongue-tie (Pacholok and Stuart, 2011; Guez et al, 2012). Infants who are breastfed by a woman with an undiagnosed vitamin B12 deficiency may be at particular risk (Pacholok and Stuart, 2011). Molecular biologist Eva Greibe found that the level of vitamin B12 in breast milk may not remain optimal, as it declines over a period of 4 months (Fedders, 2013).
Vitamin B12 deficiency is completely inclusive of the human life span, affecting fetal development (Pacholok and Stuart, 2011; Pepper and Black, 2011; NHS Choices, 2016) through to the end of life, with dementia-type symptoms being a common manifestation (Savage and Lindenbaum, 1995; Lindenbaum et al, 2008; Pacholok and Stuart, 2011; NHS Choices, 2016). Some individuals are at increased risk of deficiency. Vegans and vegetarians can be particularly susceptible, as vitamin B12 is sourced entirely from animal produce i.e. meat, fish and dairy (Walsh, 2001; Herrmann and Obied, 2008; Pacholok and Stuart, 2011; NHS Choices, 2015). In addition, individuals who have undergone gastric bypass surgery, those with eating disorders or alcoholism, and people living with Crohn's and coeliac disease, are at increased risk (Pacholok and Stuart, 2011). Long-term use of metformin, a drug commonly used in pregnancy to control raised blood glucose levels for gestational diabetes (NICE, 2015b), can interrupt the metabolism of vitamin B12, resulting in a deficiency (de Jager et al, 2010). This highlights that a number of women in the care of midwives may be at risk of vitamin B12 deficiency.
A risk that is particularly relevant to midwifery is the use of nitrous oxide (Pacholok and Stuart, 2011; BOC Healthcare, 2015; 2016). In the UK, Entonox—the combination of nitrous oxide and oxygen—is often referred to as ‘gas and air’. It is generally considered a reasonably effective and safe analgesic. However, unlike other methods of medicine administration, inhalation of a gas has the potential to contaminate the working environment (BOC Healthcare, 2015; 2016; Royal College of Midwives, 2016). The manufacturer recommends that Entonox should be administered in adequately ventilated rooms (BOC Healthcare, 2015) and the UK Health and Safety Executive has set occupational exposure to a limit of 100 ppm over 8 hours (BOC Healthcare, 2015). Entonox should not be used for more than 24 hours, or more frequently than every 4 days (BOC Healthcare, 2016). Setting guidelines for health and safety is essential to protect the wellbeing of staff. However, there are some problems in adhering to these recommendations. Many midwives now work mandatory 12-hour shifts, and their shifts are often worked consecutively; therefore, midwives are invariably exposed to Entonox more frequently than the recommended 4-day interval (BOC Healthcare, 2016). A well-ventilated room is not always available, or even safe, especially when welcoming a new baby into the world where open windows or air conditioning increase the risk of cold injury to the newborn. Not all hospitals have scavenging systems and, even if they do, it could be argued that the gas would have to reach the scavenging system before reaching the people in the room. In addition, the Entonox recommendations do not appear to account for midwives attending homebirths, where the environment is out of the practitioner's control.
A common assumption may be that, as a gas, nitrous oxide is easily dispersed. However, oxygen is the lighter gas, and nitrous oxide collects in pockets, often at floor level (Piziali et al, 1976). Many midwives supporting an active birth may spend considerable time at floor level—sometimes hours. Even practitioners caring for women at bed level remain vulnerable. Normal movement in the room disturbs these pockets of nitrous oxide, exposing anyone in the vicinity to the gas and potentially increasing the risk of developing a vitamin B12 deficiency. An awareness of the risk is vital. Midwives should observe themselves and others for any subtle changes that could be indicative of a B12 deficiency.
My advice to midwives to protect themselves and their colleagues, along with the women and infants in their care, is to think ‘B12D’:
Vitamin B12 deficiency can be devastating, but with early diagnosis and appropriate treatment a full recovery is possible. Individual holistic assessment of women and infants is essential to provide optimum care. This should include screening for vitamin B12 deficiency, and such screening should be extended to midwives when working around Entonox. When it comes to vitamin B12 deficiency, care and consideration should be given not only to women and infants, but to midwives and other health professionals.