Managing Sexually Transmitted Infections in Pregnant Women

Nadi K Gupta; Christine A Bowman

Disclosures

Women's Health. 2012;8(3):313-321. 

In This Article

Viral Infections

Genital Herpes

Both HSV types 1 and 2 can cause genital herpes. Genital herpes is the most common ulcerative STI in the UK. The presence of genital ulcers also increases the likelihood of HIV transmission.[18]

Disease episodes may be first-episode or recurrent, and symptomatic or asymptomatic. First-episode genital herpes is subdivided into primary (newly acquired infection) and nonprimary infection (first clinical episode of a previously acquired herpes infection). It can be difficult to distinguish primary infection from the first clinically apparent episode of a previously acquired infection. Primary genital herpes can be very painful and distressing. Most clinicians make a clinical diagnosis and prescribe empirical treatment after taking swabs for HSV. Full STI and HIV screening is important, but swabs are usually deferred until the lesions have healed.

The diagnosis is confirmed by obtaining a swab from the base of an ulcer. HSV DNA detection by PCR is more sensitive than culture.[19] PCR can distinguish HSV-1 from HSV-2. Serology can be difficult to interpret and may not become positive for 6–8 weeks after a primary episode. Routine serology has poor specificity. Type-specific serology is expensive and type-1-seropositivity fails to differentiate between oropharyngeal and genital herpes infections.

The main risks of genital herpes during pregnancy are first or second trimester miscarriage and neonatal herpes. The highest risk of neonatal herpes is in women who acquire HSV during the third trimester. A prospective study of 58,000 women in the USA found 202 cases where HSV was isolated at the time of labor.[20] There were ten cases of neonatal herpes. Transmission is usually from direct contact with the virus during delivery; in utero transmission can occur but is rare. Untreated neonatal herpes is associated with a high mortality and can cause disability even with appropriate timely treatment.

Treatment of HSV in Pregnancy General advice includes saline bathing and analgesia. Management of genital herpes in pregnancy is determined by the gestation of the pregnancy at the time of herpes acquisition and can be categorized into management of first episodes and recurrent episodes. However, this can be difficult to distinguish clinically. Obtaining paired serum samples for type-specific serology several weeks apart may be useful to demonstrate seroconversion (i.e., recent infection).

First-episode Genital Herpes in First or Second Trimester If first-episode genital herpes occurs in the first or second trimester, there is an association with miscarriage but there is no conclusive evidence that it causes birth defects. A 3–5 day course of aciclovir should be used to reduce the severity and duration of the episode. Although aciclovir is not licensed for use in pregnancy, it appears to be relatively safe.[21]

Prophylactic suppressive aciclovir from 36 weeks gestation may be considered in order to reduce the likelihood of a HSV outbreak at labor, ultimately reducing the likelihood of Cesarean section.[22]

In the absence of lesions or prodromal symptoms at labor, vaginal delivery should be anticipated.

First-episode Genital Herpes in Third Trimester The risk of neonatal herpes is greatest when the mother acquires herpes in the third trimester. The mother acquires herpes but is unable to develop IgG antibodies before delivery and so the baby is born without the protection of passive immunity. In this situation, there is a 30–50% risk of neonatal herpes.[22,23] Therefore, all women with first-episode genital herpes at the time of delivery or within 6 weeks of the expected date of delivery should be offered Cesarean section.[102] However, there are no published randomized controlled trials evaluating the effectiveness of Cesarean section for the prevention of neonatal herpes.

Recurrent Genital Herpes Pregnant women who acquired HSV prior to pregnancy will already have IgG antibodies to HSV and will pass these antibodies to the fetus. Neonatal herpes is uncommon in this situation. If there are HSV lesions at the time of vaginal birth, the risk of neonatal herpes is reported to be 2–5%.[24] There is a small risk of asymptomatic shedding and the risk of neonatal herpes in these cases is reported to be 0.02–0.05%.[24,25] Suppressive aciclovir should be considered from 36 weeks until delivery in order to prevent clinical recurrences and therefore reduce the need for Cesarean section.[26] Cesarean section should be considered if there are genital lesions at the onset of labor. Vaginal delivery should be anticipated if there are no lesions present at delivery. The risk of neonatal herpes following vaginal delivery is small and one must balance this against the risk of Cesarean section to the mother.[24]

Recommended regimens for HSV can be found in Box 4 (see text as above).

HPV

Genital warts are caused by infection with HPV and are the most prevalent viral STI diagnosed in the UK. Infection may not be clinically apparent.

There are over 100 documented HPV genotypes of which approximately 40 are tropic for anogenital skin. Most anogenital warts are benign; however, there are certain genotypes that are associated with an increased risk of anogenital neoplasia, specifically, genotypes 16 and 18 are associated with the greatest risk. External warts are generally due to types 6 and 11, which are not considered to be oncogenic. However, warts can also be caused by other oncogenic strains.[27,28] The most important risk of HPV infection to women is the risk of anogenital cancer. The recent introduction of HPV vaccination programs has led to a significant decrease in high-grade smear abnormalities.[29] Quadrivalent HPV vaccination has also resulted in decreased incidence of genital warts.[30]

Genital warts may increase in size and number during pregnancy. The diagnosis is usually made clinically upon visual inspection. Maternal infection is associated with juvenile laryngeal papillomatosis in the infant. This is a rare condition that can cause hoarseness and respiratory distress in children. Cesarean section is not indicated in mothers with genital warts as vertical transmission of HPV is rare.[31]

Treatment of HPV During Pregnancy The same as in nonpregnant patients, treatment is usually for cosmetic rather than medical purposes in the majority of cases. Treatment is only really necessary in the unlikely event that the warts cause obstruction of the birth canal and impede vaginal delivery. All treatments have significant failure and relapse rates[32] and no single treatment is considered to be better than another. Cryotherapy with liquid nitrogen causes cytolysis at the dermo–epidermal junction and is safe for use in pregnancy. A freeze/thaw technique should be employed, whereby liquid nitrogen is applied for approximately 10 s until a halo of freeze develops a few millimetres around the wart. This is repeated three or more times for each lesion during the treatment session. Cryotherapy can be administered every 1–2 weeks. Lesions may regress after delivery without any treatment. Podophyllin, podophyllotoxin and imiquimod should be avoided in pregnancy. Contact tracing is not required.

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