Pregnancy may make your skin glow but it can also bring on skin conditions you would not normally see with your skin.  Melasma is the dark brown or gray patches that may appear on the checks, forehead, chin and upper lip during pregnancy.  Some people refer to this condition as the "pregnancy mask" it is usually brought on by the strong hormones of pregnancy.  Sun protection is the most important treatment for melasma.  Some women lose their "pregnancy mask" after their baby is born, others continue to have these conditions for years. 

You may have escaped having acne in your teens but now that you are an expectant mother you see your skin changing.  Elevated levels of cortisone (due to stress) and/or your hormonal changes may bring on acne.  It does not help your condition to pick at your blemishes, it can lead to infection and scarring.  If you are an expectant mother and you're become acneic their are non-harmful topical treatments that can be prescribed to you.