More than 90% of women develop skin abnormalities and changes during pregnancy which can potentially have a huge impact on their life.1 These skin changes can be very distressing for women, so it is important that as practitioners we are able to offer safe and effective treatment plans. This article explores how we can achieve this with appropriate skincare.
Women experience many physiological changes during pregnancy, including hormonal increases (such as oestrogen, progesterone, prolactin, b-HCG), a shift in blood flow to account for the developing foetus, a change in immune response and also changes to the metabolism of proteins, lipids and carbohydrates.2 As these physiological alterations occur, skin abnormalities may develop as a consequence, including pigmentation issues and acne. These disorders are attributed mainly to the rise in oestrogen and progesterone, making them most prevalent in the second and third trimester as the placenta develops.2
Hyperpigmentation
Pigmentation issues, particularly melasma, are the most common skin complaints during pregnancy, affecting approximately 50-70% of patients.3 It can often be referred to as the ‘mask of pregnancy’. Melasma is derived as oestrogen and progesterone stimulate the melanocytes to produce more melanin pigments when exposed to UV light.4 It starts from the first trimester of pregnancy and may continue throughout.
Melasma is generally a clinical diagnosis consisting of symmetric reticulated hypermelanosis in three predominant facial patterns: centrofacial, malar and mandibular. The major clinical pattern in 50-80% of cases is the centrofacial pattern, which affects the forehead, nose and upper lip. The malar pattern is restricted to the malar region of the cheeks on the face, whilst mandibular melasma is present on the jawline and chin.4
The first line of management for melasma is to avoid direct sunlight where possible and wearing daily SPF 30+. This is demonstrated by a study performed by Lakhdar et al. who found that from 200 pregnant patients who wore SPF 50+ and UVA protection factor, only 2.7% of these developed melasma during pregnancy.5
The most suitable sunscreen is a physical sunscreen as this is not absorbed through the skin and is less irritating (especially as the skin can become more sensitive during pregnancy). These work by forming a protective layer, often made up of titanium dioxide and zinc oxide molecules, on the skin which reflects and scatters UV radiation. There has been some controversy around the use of chemical sunscreens in pregnancy due to their use of the organic compound benzophenone-3 (BP-3). It was suggested that BP-3 could penetrate the blood-placenta barrier and induce toxicity and abnormal development of the foetus.6 Yet, even at higher doses they do not penetrate the skin barrier and can therefore be considered safe.7
Hydroquinone
The gold standard treatment for hyperpigmentation is hydroquinone with tretinoin and steroids (triple therapy). It exerts its effect by inhibiting tyrosinase, the rate-limiting enzyme in melanin synthesis. Hydroquinone also affects the membranous structures of melanocytes and causes their apoptosis. Yet, research has shown that 35-45% is systemically absorbed following topical use in humans, and within a few minutes, levels are measurable in urine.8,9
When applied topically throughout pregnancy to 68 women in a study by Mahe et al. there were no adverse outcomes from its use during pregnancy when compared to the control sample.10 Yet, given that this was such a small sample size, and the fact its systemic absorption is so high, its use is absolutely contraindicated in pregnancy. Studies are limited in this area due to the risks associated with testing treatments during pregnancy, and the ethical implications limits further work which would need to be done in this area to come to an absolute conclusion.
Alternatives
During pregnancy it is advised that alternatives such as vitamin C be used.11,12,13 Vitamin C inhibits melanogenesis by acting as a reducing agent at various oxidative steps in melanin synthesis. Additionally, niacinamide can be used in conjunction with vitamin C. This is the active amide of vitamin B3 that reduces pigmentation by inhibiting the transfer of melanosomes to keratinocytes.11
There are also alpha-hydroxy acids (AHAs) such as glycolic, lactic and mandelic to improve the treatment of skin pigmentation. At low concentrations they reduce the cohesion of the corneal extract corneocytes and stimulate the proliferation of cells in the epidermis.14,15
Acne
Acne is most common during the first and second trimesters of pregnancy, affecting up to 42% of patients.16 An increase in progesterone levels causes glands to grow and produce more sebum, which results in an accumulation of cellular debris and hyperkeratosis. This promotes microbial proliferation and inflammatory processes which cause acne breakouts.15
Standard topical treatment for acne usually includes retinoids, antibacterial agents, benzoyl peroxide and salicylic acid, but this needs to be adjusted during pregnancy.18
Topical retinoids/vitamin A
Systemic retinoid medications are an absolute contraindication during pregnancy due to their known teratogenic qualities. There have been four published reports of birth defects associated with topical tretinoin use, consistent with retinoid embryopathy.19-22 These studies reported ear, eye and central nervous system malformations of the individual patients.23 Additional risks were thought to include miscarriage and premature delivery, yet research has proven this to be insignificant.24 Further meta-analysis to rule out any risk of the use of both oral and topical retinoids across 654 pregnant women has been suggested to be statistically safe, yet this is still not enough to justify use throughout pregnancy.24
Alternatives
Benzoyl peroxide has strong keratolytic, comedolytic and antibacterial properties.23 Approximately 5% is absorbed systemically, and it is completely metabolised into benzoic acid. Because of rapid renal clearance, no systemic toxicity is expected, and the risk of con-genital malformations is theoretically small.23
Azelaic acid exerts broad antimicrobial effects via an unknown mechanism and has a well-documented safety profile during pregnancy due to only 4% of the drug being absorbed after topical application.25 Research has also shown nil adverse effect on foetuses and newborn animals, even when administered in high doses during pregnancy.26 Azelaic acid is a naturally occurring dicarboxylic acid with antimicrobial, comedolytic and mild anti-inflammatory properties, with an added benefit of decreasing post-inflammatory hyperpigmentation.27 Therefore this is an ideal multi-tasking ingredient that can be used for a number of skin conditions during pregnancy.
Both beta hydroxy acids (BHAs) and AHAs are frequently used for acne treatment.18 These acids promote cell shedding on the surface of the skin and help to restore hydration. Salicylic acid is a popular BHA for acne treatment and the situation for topical use and potential toxicity in pregnancy is minimal.8 This contrasts with therapeutic doses of oral salicylates, which due to their antiprostaglandin properties cause reduced birth weight, increased blood loss at delivery and increased perinatal mortality.28 Mandelic acid is a safe and effective AHA which is used for both acne and melasma and is also highly suited to skin of colour patients.29
Another point to consider is the rising use of prebiotics to treat acne.30 These pregnancy-safe ingredients are an alternative to those who wish to treat acne without the use of acids or retinol. Noni stem cells are able to prevent the growth of acne-causing bacteria, whilst allowing the beneficial flora to thrive.31 Bioflavonoids imitate the effect of retinoic acid on the skin, without the common side effects of retinol such as drying and irritation.31
Striae gravidarum
Striae gravidarum (stretch marks) develop in approximately 90% of pregnant women and can cause significant emotional and phycological distress.32 They form as the dermis becomes stretched and broken in places. Reliable methods to prevent their formation are scarce, and current techniques such as applying cocoa oil or olive oil has been proven to be ineffective.32
Instead, it is recommended to maintain a healthy diet and lifestyle throughout pregnancy as per NHS guidance to help to minimise excessive weight gain, and therefore theoretically reduce the risk of striae gravidarum formation.33
Keeping patients safe
Although there are some clear contraindications for active ingredients during pregnancy, we can still formulate beneficial plans focusing on barrier building and reducing inflammation to help our pregnant patients manage their skin conditions effectively during pregnancy and aid their overall wellbeing during this special time. In addition, it is important to give specific advice to patients regarding the amount and application of products to be sure they remain well within safe limits.
