Chapter 15 Sexually Transmissible and Reproductive Tract Infections in Pregnancy
Trends in sexual health
Trends of particular concern are the high rates of and increase in sexually transmitted infection (STI) diagnoses particularly in women aged 16–24. Most at risk are those who have high numbers of sexual partners, partner change and unprotected sexual intercourse.
Multidisciplinary team work
Joint management between an obstetrician and a genitourinary medicine (GUM) physician during pregnancy is essential for women with infections that are serious, life-threatening, or both, such as human immunodeficiency virus (HIV); in addition, a paediatrician is required in the care and management of the neonate infected through vertical transmission. The midwife plays a vital role in the provision of individualised care throughout pregnancy, labour and the puerperium.
Infections of the vagina and vulva
There are three main types of vaginal and vulval infection:
Trichomoniasis
Trichomoniasis is almost exclusively sexually transmissible. It is caused by infection with the parasite Trichomonas vaginalis, a round or oval flagellated protozoan. Common symptoms include:
However, 10–50% of women are asymptomatic. Vaginal discharge is present in up to 70% of cases and may vary in consistency from thin and scanty to profuse and thick. A classic frothy yellow–green discharge occurs in 10–30% of women. Dyspareunia, mild dysuria and lower abdominal pain may also be experienced.
Trichomoniasis in pregnancy
Trichomoniasis has been linked with a small risk of preterm birth and low birth weight, and an increase in the risk of HIV via sexual intercourse. Trichomoniasis may be acquired perinatally.
Treatment
The recommended treatment is metronidazole daily for 5–7 days or in a single dose. Although it is contraindicated, meta-analyses have concluded that there is no evidence of teratogenicity from its use in women during the first trimester of pregnancy.
Clotrimazole pessaries daily for 7 days can be used in early pregnancy. High single-dose regimens should be avoided during pregnancy and breastfeeding.
It is usual to treat the partner(s) and advise against sexual intercourse until the treatment is completed.
In addition, patients should be advised not to take alcohol during the treatment and for at least 48 hours afterwards, as this may cause nausea and vomiting.
Bacterial Vaginosis
Bacterial vaginosis (BV) is the most common cause of vaginal discharge in women of childbearing age. It can arise and remit spontaneously in sexually active and non-sexually active women. It often coexists with other STIs. It is more common in:
In this condition the normal lactobacilli-predominant vaginal flora are replaced with a number of anaerobic bacteria. The vaginal epithelium is not inflamed; hence the term ‘vaginosis’ rather than ‘vaginitis’. The main symptom is a malodorous and greyish watery vaginal discharge, although approximately 50% of women are asymptomatic. The odour is usually more pronounced following sexual intercourse owing to the release of amines by the alkaline semen. Vulval irritation may occur in about one-third of women.
BV in pregnancy
BV is present in up to 20% of women during pregnancy, although the majority are asymptomatic. BV during pregnancy is associated with preterm birth, low birth weight, preterm premature rupture of membranes, intra-amniotic infection and postpartum endometritis.
Diagnosis
A diagnosis of BV is confirmed if three of the following criteria are present:
a thin, white to grey, homogeneous discharge
‘clue cells’ on microscopy (squamous epithelial cells covered with adherent bacteria)
the release of a fishy odour when potassium hydroxide is added to a sample of the discharge.
A Gram-stained vaginal smear is another diagnostic technique.
Treatment
Antibiotic therapy is highly effective at eradicating infection and improving the outcome of pregnancy for women with a past history of preterm birth.
The treatment regimen is the same as for trichomoniasis.
Alternative treatments include oral clindamycin, intravaginal clindamycin cream or metronidazole gel.
All these treatments have been shown in controlled trials to achieve cure rates of 70–80% after 4 weeks, but recurrences of infection are common.
Women should be advised to avoid vaginal douching, use of shower gel and use of antiseptic agents or shampoo in the bath.
Candidiasis
Candidiasis is a common cause of vulvitis, vaginitis and vaginal discharge. The causative organism is usually Candida albicans, a fungal parasite. It is a commensal and is found in the flora of the mouth, gastrointestinal tract and vagina. Colonisation of the vagina and vulva may be introduced from the lower intestinal tract or through sexual intercourse. During the reproductive years 10–20% of women may harbour Candida species but remain asymptomatic and do not require treatment. Predisposing factors that encourage C. albicans to convert from a commensal to a parasitic role are listed in Box 15.1.
Box 15.1 Factors that provoke the conversion of Candida albicans from a commensal to a parasite
The signs and symptoms of candidiasis include:
intense vulval pruritus and soreness
often, a thick, white curdy discharge (not always present)
erythema and oedema of the vulva, vagina and cervix may be erythematous and oedematous
white plaques of the vulva, vagina and cervix
Candidiasis in pregnancy
Vaginal candidiasis is found 2–10 times more frequently in pregnant than in non-pregnant women and it is more difficult to eradicate.
Diagnosis
Vaginal culture is the most sensitive method currently available for detecting Candida cells.
Treatment
Candidiasis is treated primarily with antifungal pessaries or cream inserted high into the vagina at night. Preparations that may be given include:
Diflucan is available from chemists without a prescription but this form of treatment has not been tested in pregnancy and it cannot be assumed to be safe. It should also be used with caution whilst breastfeeding owing to toxic effects in high doses.
Recurrence is common. This may be due to resistant cases or failure to complete the treatment. It is usual to treat the partner and advise against sexual intercourse until the treatment is completed. Vaginal douches and perfumed products should be avoided and tight-fitting synthetic clothing should be discouraged.
Bacterial infections
Chlamydia
Chlamydia trachomatis is an intracellular bacterium. It is the most common cause of sexually transmitted bacterial infection and a leading cause of PID.
Serotypes D–K are sexually transmitted and are important causes of morbidity in both sexes.
Serotypes A, B and C cause trachoma and blindness
Serotypes L1–L3 cause the genital disease lymphogranuloma venereum.
Chlamydial infection is asymptomatic in approximately 80% of cases. Some women may have a purulent vaginal discharge, postcoital or intermenstrual bleeding, lower abdominal pain, mucopurulent cervicitis and/or contact bleeding. Chlamydial infection of the cervix is found in 15–30% of women attending GUM clinics, and concurrently in 35–40% of women with gonorrhoea. Specific high-risk groups include:
those with a new sexual partner or more than one sexual partner in recent years
those not using barrier contraception
those using oral contraception
Chlamydial infection has been estimated to account for 40% of ectopic pregnancies.
Fetal and neonatal infections
The major risk to the infant is from passing through an infected cervix during birth. Up to 70% of babies born to mothers with chlamydial infection will become infected, with 30–40% developing conjunctivitis and 10–20% a characteristic pneumonia. The incubation period of chlamydial ophthalmia is 6–21 days. Chlamydial pneumonia usually occurs between the 4th and 11th weeks of life. It affects about half the babies who develop conjunctivitis but is not always preceded by it. The pharynx, middle ear, rectum and vagina are also targets for infection, with a delay of up to 7 months before cultures become positive.
Diagnosis
Nucleic acid amplification (NAA) tests should be used to screen women for genital chlamydial infection.
Treatment
Genital chlamydial infections are sensitive to three classes of antibiotic:
The tetracyclines and the fluoroquinolones are currently contraindicated in pregnancy. Erythromycin has long been the preferred treatment for cervical chlamydial infection despite its gastrointestinal effects. Erythromycin is also used for chlamydial infections in infants, young children and pregnant and lactating women. Single-dose azithromycin is expensive but gaining favour because of its effectiveness, low incidence of adverse gastrointestinal effects and enhanced compliance.
Gonorrhoea
Gonorrhoea is caused by Neisseria gonorrhoeae, a Gram-negative diplococcus. Transmission is by sexual contact. This organism adheres to mucous membranes. The primary sites of infection are therefore the mucous membranes of the urethra, endocervix, rectum, pharynx and conjunctiva. Gonorrhoea may coexist with other genital mucosal pathogens, notably T. vaginalis, C. albicans and C. trachomatis. Gonorrhoea is a major cause of PID. The sequelae of PID include:
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