••• Chapter 63^ Reproductive Toxicology^629
❍ A patient asks you about caffeine intake during pregnancy. What do you tell her?
Studies about the effects of caffeine on pregnancy report conflicting results. Of the studies that do show that
caffeine is harmful to pregnancy, the effects seem to be most significant when caffeine intake is >300 mg/
day (about three cups of coffee per day). Caffeine may be associated with IUGR when consumed in these
quantities.
❍ Is the hot tub or sauna dangerous to pregnancy?
The American College of Obstetricians and Gynecologists (ACOG) states that becoming overheated in a hot tub
or sauna is not recommended during pregnancy and its use in the first trimester is associated with neural tube
defect (RR 2.8). The ACOG also recommends that pregnant women never let their core body temperature rise
above 102.2° F. If a pregnant woman wishes to use the hot tub, then its temperature should be lowered, and she
should not spend >10 minutes in the warm water.
❍ What are the special concerns of flying during pregnancy?
The ACOG recommends women not to fly after their 36th week of pregnancy. Airlines have their own
flight restrictions for pregnant women, which can vary according to whether she is flying domestically or
internationally. Most airlines won’t take pregnant women past 36 weeks, even on short-haul flights of 2 hours,
and most of the travel insurance won’t cover her late in pregnancy, usually from around 32 weeks.
Also a single, long international flight due to thinner portion of the atmosphere increases radiation exposure
to a week’s worth of natural background radiation, however, is far from a health concern, even for pregnant
women. But aviation workers can easily exceed the recommended safe limits, which is 20 millisieverts
(mSV) a year. (For scale, a person at ground level gets about 2.4 mSv of natural background radiation a
year.) Other risks from flying result from cramped seating, dehydration, which increases the risk of deep
vein thrombosis.
❍ Your dermatologist colleague asks you if he can prescribe tetracycline to a pregnant patient for her severe
acne. What do you advise him?
Tetracycline and its derivatives should not be used after 16 weeks’ gestation and in childhood up to the age of 8 due
to its effects on calcium-containing tissue, particularly teeth. Tetracycline might cause permanent discoloration of
the teeth (yellow or brown) and enamel hypoplasia (a small pit or dent in the tooth or can be widespread that the
entire tooth is small and/or mis-shaped). There are no adequate and well-controlled studies in pregnant women
regarding the topical use of tetracycline solutions; however, animal studies have shown no harm to the fetus with
topical applications.
❍ Your pregnant patient is complaining of severe acne and asks your advice on safe treatment options.
What do you recommend?
Many women have trouble with acne during pregnancy because of overproduction of sebum due to hormonal
changes. Acne treatment in pregnancy starts with self-care, such as cleaning the face twice a day with lukewarm
water and avoiding resting hand on the face or picking/scratching acne sores. Patient should be advised to use
oil-free cosmetics that are noncomedogenic.
Second-line treatment involves topical erythromycin (Erygel), which is the drug of choice for pregnancy acne.
Azelaic acid (Azelex, Finacea) may be another topical option. Opinions about using benzoyl peroxide to treat
pregnancy acne are mixed and its potential teratogenic risk is undetermined, but there are no case reports about
benzoyl peroxide and birth defects in the literature.