PREGNANCY AND BREASTFEEDING

Pregnancy

Removal during pregnancy is often requested by the patient and can be performed with ablative methods.(90) HPV types 6 and 11 can, rarely, cause laryngeal papillomatosis in infants and children. A Danish study reported an incidence of seven per 1000 where there was a documented history of external genital warts.(91) Tasca and Clarke report an overall incidence of 3.5 per million person-years and a prevalence of four cases per 100,000 children.(92) In babies born to mothers with genital warts, HPV DNA can be isolated from aerodigestive swabs in a third to a half of cases; however, the risk of development of RRP is approximately 1 in 400. Presentation can be at any age, but typically it is at 3–4 years with progressive hoarseness.

Although there appears to be an association between maternal genital warts during vaginal delivery and laryngeal papillomatosis, the route of transmission (transplacental, perinatal, or postnatal) is not completely understood. HPV DNA has been detected in amniotic fluid, raising the possibility of ascending infection, and HPV DNA has been detected in the peripheral blood mononuclear cells of mothers and in cord blood samples.(93) Although this may suggest transmission via a haematogenous route, transmission via microscopic tears in the placental membranes, as occurs with other organisms, is a more likely explanation.(94)

There has been a wide variation in reported neonatal transmission rates for HPV, although larger studies using more recent HPV DNA technology indicate that transmission rates are low.(95,96) In a study of 574 women, 47.1% were identified as being HPV DNA positive (mainly in the third trimester) at age ≤24 and 24.4% at age >24 years. However, 1.6% of newborns were HPV DNA positive at a mean of 65 hours after birth.(97) Non-concordance between parental and neonatal HPV types suggests the possibility of maternal infection acquired antenatally at untested intervals during pregnancy or, in the case of oral infection, from other contacts after birth.(98)

Follow-up studies of infants from whom HPV DNA was isolated at birth indicate that the virus becomes undetectable in many infants, indicating that contamination rather than true infection has occurred.(99) It has also been demonstrated that HPV 16 antibodies detected at birth will clear from the infant within 10 months, but not from the mother.(99)

In summary, although HPV infection is frequently detected in pregnant women, detection of HPV in newborns is uncommon and is likely to be due to contamination.

Although caesarean section reduces the risk of HPV isolation from the neonate, it has not been shown to significantly reduce neonatal transmission of HPV, nor of laryngeal papillomatosis.(91) Many studies have been limited by lack of long-term follow-up and assessment of only HPV positivity rates after birth.(100) Caesarean delivery should not be performed solely to prevent transmission of HPV infection to the newborn. In rare instances, caesarean section delivery may be indicated for women with very large genital warts if the pelvic outlet is obstructed or if vaginal delivery would result in excessive bleeding.

Treatment during pregnancy requires some special considerations. Podophyllin and podophyllotoxin should not be used in pregnancy. Maternal and fetal deaths have been reported following the use of podophyllin for large vascular warts. Imiquimod is not recommended as there is insufficient data to recommend its use in pregnant women. Individual case reports and a small case series have been published.

HPV in pregnancy has no link with miscarriage, premature labour or other types of pregnancy complications.

Treatment recommendations

• Appropriate treatments of external genital warts during pregnancy include cryotherapy, surgical removal and laser ablation.
• Podophyllin and podophyllotoxin should not be used in pregnancy. GRADE C
• Imiquimod is not recommended.
• Caesarean section does not significantly reduce vertical transmission and is only indicated when genital warts are likely to cause obstruction of the pelvic outlet or excessive bleeding. GRADE B

Breastfeeding

The use of podophyllin and podophyllotoxin are not recommended in women who are breastfeeding because of systemic absorption. The New Zealand Formulary states imiquimod can be used in breastfeeding. No quantifiable levels of imiquimod are detected in breast milk. The manufacturers give no specific instructions on the use of imiquimod in lactation. Ablative methods can be used during lactation.