Do moles grow bigger during pregnancy

There are many myths surrounding the changes that a body undergoes during pregnancy, and moles are no exception. Dermatologists and other health care providers likely emphasize the importance of monitoring any change in your moles from color, to size, to texture. This is important because changing moles may indicate something more serious like melanoma for some individuals.

Mole changes during pregnancy can be difficult to identify, as the body is constantly transforming during this time, and moles may alter in shape and size due to their location. Some researchers have also suggested that extra hormones in the body can contribute to changes in mole appearance.^[1] Read on to learn about the most current information on changing moles during pregnancy, dispel any myths, and give you a framework for approaching your changing moles during pregnancy.

ABC…and DE’s of Changing Moles

Before we discuss changing moles in pregnancy, it is worthwhile to discuss changing moles in general and what concerning signs and symptoms should prompt one to seek care from a primary care provider or dermatologist. ABCD was an acronym developed by a group of dermatologists in 1985 to assist patients in recognizing any foreboding changes to their moles. Unfortunately, this does not help screen for all types of melanoma such as “amelanotic” kinds, which do not have any color/pigment. Also, other benign skin lesions may also exhibit ABCD changes. Therefore, the letter “E” has been added to the acronym to increase its usefulness. Regardless of the acronym’s specificity (how often the tool’s diagnosis of melanoma is actually melanoma), it is still important to regularly monitor for suspicious changes.^[2]

• “A” stands for asymmetry: Moles in which one half looks different from the other half in color, shape, or texture are more likely to be malignant (cancerous).^[3]
• “B” stands for border: Moles that do not have smooth, regular edges, but rather jagged, irregular borders are more concerning.^[3]
• “C” stands for color: Moles that have several different colors within the lesion instead of all being one color can be dangerous. Colors can range from tan, brown, black, white, red, and sometimes blue.^[3] 
• “D” stands for diameter: Big is bad. Moles that are > 6mm in diameter should be examined.^[3] 
• “E” stands for evolution: This is one of the most important letters in the acronym and is sometimes called “the ugly duckling” sign. Moles that do not look like the other moles on your body or moles that start looking different from what they’ve always looked like are very concerning.^[3]

Changing Moles During Pregnancy

For years, physicians have believed that the hormones associated with pregnancy, like estrogen and progesterone, have contributed to the natural and non-concerning enlargement and darkening of pre-existing moles in pregnant women. Recent evidence in the literature; however, does not support these notions. In fact, this belief may have led to many missed diagnoses of melanoma in pregnant women, as these changes were regarded as simple changes of pregnancy.^[1]

This is not to say that pregnancy cannot affect the appearance of moles. A key factor in this distinction is the location of the moles. Moles on the front of the body in locations such as the breast or abdomen tend to expand due to stretching of the skin that occurs with increasing breast size and an expanding abdomen. However, this is not true of moles that are located in other areas of the body not affected by skin stretching. These moles do not naturally increase in size due to pregnancy, and it is more concerning if size changes are noticed.^[1]

Changing mole color is harder to study based on subjective measurements (patients and physicians looking at the moles and assessing darkness). However, recent studies using spectrophotometry to assess actual pigmentation levels within lesions have provided evidence against the claim that moles naturally darken during pregnancy.^[1,4] 

With this information in mind, changes in moles during pregnancy should not necessarily be considered benign. If a mole is changing during pregnancy, a healthcare provider should be notified and the appropriate steps taken to further assess whether the mole should be removed. If a biopsy of the mole is needed based on communication with a dermatologist, the biopsy should not wait until after the pregnancy. It should be considered for a prompt biopsy, just how it would be treated in a non-pregnant woman.^[1]

Melanoma During Pregnancy 

There have been many myths surrounding the diagnosis of melanoma during pregnancy. It was a commonly held belief that malignant melanoma was more aggressive and deadly in pregnancy. However, recent studies have shown that pregnancy does not play a role in the survival time of a patient diagnosed with malignant melanoma. Also, women should only consider delaying future pregnancies based on life expectancy changes that the tumor may cause. For example, if the melanoma is thin and considered to be early stage, subsequent pregnancy does not have to be delayed. Delaying pregnancy for 2-3 years is an option for women with more aggressive diseases who have a higher chance of the tumor recurring.^[5]

Safety of Anesthetic Agents for a Biopsy During Pregnancy

A skin biopsy usually requires the use of a small amount of local anesthetic to numb the area. The safety of anesthetics, even local preparations, in pregnant women is a common question many patients have. Unfortunately, there is limited data and information on the safety of topical and local anesthetic use in pregnant women. Of the injectable local anesthetics, lidocaine is considered relatively safe (pregnancy category B) to use in pregnant women, especially at the small doses used for dermatologic procedures such as local skin biopsies. There is a risk to fetus brain and heart health if higher doses are used or if the substance is accidentally injected into the artery. However, this is uncommon and the doses used for skin biopsies are relatively small.^[6]

Benzocaine, bupivacaine, mepivacaine, and tetracaine injectables are all considered to not have enough studies to adequately define risk during pregnancy.^[6]