Epidemiology suggests that melanin inhibits cutaneous vitamin D 3 synthesis by UVR. Laboratory investigations assessing the impact of melanin on vitamin D production have produced contradictory results. We determined the effect of melanin on vitamin D 3 photosynthesis in healthy young volunteers (n ¼ 102) of Fitzpatrick skin types II-VI (white to black). Participants, irrespective of skin type, were exposed to the same suberythemal UVR dose, to 85% body surface area, using solar simulated UVR or narrowband UVB (311 nm). This was repeated five times with intervals of 3e4 days between UVR exposures. Blood was taken before, during, and after the irradiation and assessed for serum 25-hydroxyvitamin D 3 (25[OH]D 3) as a marker of vitamin D 3 status. Linear UVR dose-dependent increases in 25(OH)D 3 were highly significant (P 7.7 x 10-11). The ratios of regression slopes of the different skin type groups were compared, and only skin type II was significantly steeper than the other groups. Comparisons between extreme skin types II and VI showed melanin inhibition factors of approximately 1.3e1.4, depending on the UVR source. We conclude that the inhibitory effect of melanin on vitamin D 3 synthesis is small, compared with erythema, but that this difference may be sufficient to explain the epidemiological data.

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The prevalence of aesthetic procedures has increased exponentially over the last decade. Pregnancy causes many aesthetic changes in a woman, such as melasma, hirsutism and striae. Although these are temporary in most cases, they can be distressing to the mother. As such, the desire to undergo aesthetic procedures can increase during this period. A variety of procedures exist, however, their safety profiles have usually been determined by tests on non-pregnant volunteers. The changes that occur in pregnancy and the presence of a foetus, which is susceptible to a wider range of toxins, means this data cannot be directly transferred to dictate pregnancy safety profiles. In general, most aesthetic procedures and agents are deemed to be safe to use in pregnancy, however, the health of both mother and foetus should be paramount. Aesthetic procedures are non-urgent, therefore, best practice would be to centre consultations on patient counselling, encouraging patients to delay procedures until after pregnancy.

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