Editing Acne (section)

===Pregnancy===
Although sebaceous gland activity in the skin increases during the late stages of pregnancy, pregnancy has not been reliably associated with worsened acne severity.<ref name="Tyler2015"/> In general, topically applied medications are considered the first-line approach to acne treatment during pregnancy, as they have little systemic absorption and are therefore unlikely to harm a developing [[fetus]].<ref name="Tyler2015">{{cite journal | vauthors = Tyler KH | title = Dermatologic therapy in pregnancy | journal = Clinical Obstetrics and Gynecology | volume = 58 | issue = 1 | pages = 112–8 | date = March 2015 | pmid = 25517754 | doi = 10.1097/GRF.0000000000000089 | s2cid = 31034803 | type = Review }}</ref> Highly recommended therapies include topically applied [[benzoyl peroxide]] ([[pregnancy category]] C) and azelaic acid (category B).<ref name="Tyler2015"/> Salicylic acid carries a category C safety rating due to higher systemic absorption (9–25%), and an association between the use of anti-inflammatory medications in the third trimester and adverse effects to the developing fetus including [[oligohydramnios|too little amniotic fluid in the uterus]] and early closure of the babies' [[ductus arteriosus]] blood vessel.<ref name=Kong2013/><ref name="Tyler2015"/> Prolonged use of salicylic acid over significant areas of the skin or under [[occlusive dressing|occlusive (sealed) dressing]]s is not recommended as these methods increase systemic absorption and the potential for fetal harm.<ref name="Tyler2015"/> Tretinoin (category C) and adapalene (category C) are very poorly absorbed, but certain studies have suggested [[teratogen]]ic effects in the first trimester.<ref name="Tyler2015"/> The data examining the association between maternal topical retinoid exposure in the first trimester of pregnancy and adverse pregnancy outcomes is limited.<ref name="Kaplan2015">{{cite journal | vauthors = Kaplan YC, Ozsarfati J, Etwel F, Nickel C, Nulman I, Koren G | title = Pregnancy outcomes following first-trimester exposure to topical retinoids: a systematic review and meta-analysis | journal = The British Journal of Dermatology | volume = 173 | issue = 5 | pages = 1132–41 | date = November 2015 | pmid = 26215715 | doi = 10.1111/bjd.14053 | s2cid = 41362332 | type = Systematic Review & Meta-Analysis }}</ref> A systematic review of observational studies concluded that such exposure does not appear to increase the risk of major [[congenital malformations|birth defects]], [[Spontaneous abortion|miscarriages]], [[stillbirth]]s, [[premature birth]]s, or [[low birth weight]].<ref name="Kaplan2015"/> Similarly, in studies examining the effects of topical retinoids during pregnancy, fetal harm has not been seen in the second and third trimesters.<ref name="Tyler2015"/> Nevertheless, since rare harms from topical retinoids are not ruled out, they are not recommended for use during pregnancy due to persistent safety concerns.<ref name="Kaplan2015"/><ref name="Meredith2013">{{cite journal | vauthors = Meredith FM, Ormerod AD | title = The management of acne vulgaris in pregnancy | journal = American Journal of Clinical Dermatology | volume = 14 | issue = 5 | pages = 351–8 | date = October 2013 | pmid = 23996075 | doi = 10.1007/s40257-013-0041-9 | s2cid = 13637965 | type = Review }}</ref> Retinoids contraindicated for use during pregnancy include the topical retinoid tazarotene, and oral retinoids isotretinoin and [[acitretin]] (all category X).<ref name="Tyler2015"/> Spironolactone is relatively contraindicated for use during pregnancy due to its antiandrogen effects.<ref name=Vary2015/> Finasteride is not recommended as it is highly teratogenic.<ref name=Vary2015/>

Topical antibiotics deemed safe during pregnancy include clindamycin, erythromycin, and metronidazole (all category B), due to negligible systemic absorption.<ref name=Kong2013/><ref name="Tyler2015"/> [[Nadifloxacin]] and dapsone (category C) are other topical antibiotics that may be used to treat acne in pregnant women but have received less study.<ref name=Kong2013/><ref name="Tyler2015"/> No adverse fetal events have been reported from the topical use of dapsone.<ref name="Tyler2015"/> If retinoids are used there is a high risk of abnormalities occurring in the developing fetus; women of childbearing age are therefore required to use effective [[birth control]] if retinoids are used to treat acne.<ref name=BMJ2013/> Oral antibiotics deemed safe for pregnancy (all category B) include [[azithromycin]], [[cephalosporin]]s, and [[penicillin]]s.<ref name="Tyler2015"/> Tetracyclines (category D) are contraindicated during pregnancy as they are known to deposit in developing fetal teeth, resulting in yellow discoloration and [[enamel hypoplasia|thinned tooth enamel]].<ref name=Vary2015/><ref name="Tyler2015"/> Their use during pregnancy has been associated with the development of [[acute fatty liver of pregnancy]] and is further avoided for this reason.<ref name="Tyler2015"/>