Abstract
Sexually transmitted infections (STIs) directly impact sexual and reproductive health, with a particular burden in women. They can lead to significant adverse complications and outcomes during pregnancy, and infertility. Antenatal care guidance focuses on a holistic approach, ensuring risk assessments are carried out at every appointment. Except for performing hepatitis B/HIV/syphilis serology at booking appointments, STIs are often overlooked. There are no explicit recommendations on when to perform STI screening tests during pregnancy. Given the current burden (and potential impact) of STIs, it is imperative these are considered during antenatal appointments and screened for appropriately. Early detection and treatment are necessary to secure good outcomes for the pregnant person and fetus. Partner notification is essential to halt transmission and prevent reinfection. Management should be via a multidisciplinary, cross-specialty approach. In this article we review various (non-HIV) STIs in pregnancy – focusing on presentation, diagnosis, management, and possible complications of each.
Introduction
Sexually transmitted infections (STIs) are continuing to increase in incidence and prevalence, with the World Health Organization (WHO) estimating that each day more than 1 million curable STIs are acquired worldwide in people aged between 15 and 49 years old. Most of these infections are asymptomatic.
The most recent data from the United Kingdom Health Security Agency (UKHSA), Public Health Scotland (PHS), and Public Health Wales (PHW), show that a significant proportion of this increase is in women and others who can become pregnant, particularly at child-bearing age [Please note, throughout this article, the term ‘women’ may be used. It is acknowledged that there are people who are pregnant who do not identify with this term. Where this term has been used, it should be taken to also include those people]. Chlamydia remains the most common STI in all of the UK nations, with gonorrhoea being the second most common. Rates of gonorrhoea and syphilis in particular are at historical highs.
All STIs can increase the chance of adverse events in pregnancy for both the pregnant person and the developing fetus. Furthermore, the presence of some STIs during pregnancy and at birth can lead to infection in the newborn, some with devastating consequences. Co-infection with multiple STIs is common and a full screen, including HIV, should be offered when a patient is diagnosed with a singular condition.
Treatment of many STIs during pregnancy involves the utilization of antibiotics ‘off-label’ and therefore requires a documented discussion of uncertainties, as well as the potential risks and benefits of treatment options with the patient. Pregnant and breastfeeding individuals should not be treated with quinolone or tetracycline antimicrobials, leading to alternative treatment regimens being recommended for several STIs in pregnancy.
Partner notification and treatment in pregnancy may be considered of particular importance, as reinfection may contribute to adverse outcomes of pregnancy.
Some recent positive news related to STIs includes that prevalence of genital warts remains low within the UK nations, largely due to good uptake of HPV vaccination. In Scotland, there have been no cases of cervical cancer detected in fully vaccinated women since the programme began in 2008. Studies have shown that the meningococcal B vaccine (4CMenB) appears to have an effectiveness of 32–42% at preventing gonorrhoea infection and has been recommended by the Joint Committee on Vaccine and Immunisation (JCVI) to be offered to certain individuals at increased risk of infection. There is also growing interest in using doxycycline as post-exposure prophylaxis (doxy-PEP) in certain individuals to prevent infection from STIs (namely syphilis and chlamydia, and to a lesser degree, gonorrhoea).
Chlamydia
Genital chlamydia infection is caused by the obligate intracellular bacterium Chlamydia trachomatis . Chlamydia remains the most commonly reported bacterial STI in the UK, with 194,970 infections recorded in England in 2023. One third of these were in young women between the ages of 15–25 years old, with test positivity rates in this age group remaining stable at around 9.7%.
Introduction of the National Chlamydia Screening Programme in England since 2003 focusses on opportunistic screening for young women and other young people with womb or ovaries aged 15–24 years old only. NICE guidelines do not currently support universal screening for chlamydia in pregnancy. However, they do recommend all pregnant people aged less than 25 years old are informed about the high prevalence of chlamydia infection in their age group, advised about possible adverse effects of infection and directed to available testing services.
Person-to-person transmission is primarily through penetrative sexual intercourse with co-infection at rectal or extragenital sites found to be high across several studies. Diagnosis is via vulvovaginal or endocervical swab, either clinician or self-taken, sent for high sensitivity nucleic acid amplification tests (NAAT) polymerase chain reaction (PCR).
Most genital chlamydia infections are asymptomatic. Some patients do, however, experience symptoms of increased vaginal discharge; post-coital and intermenstrual bleeding; dysuria; lower abdominal pain; and/or deep dyspareunia. Clinical signs can include mucopurulent cervicitis with or without contact bleeding; pelvic tenderness and cervical motion tenderness.
Complications of untreated chlamydia infection include ectopic pregnancy, pelvic inflammatory disease (PID), and tubal infertility. In pregnancy, chlamydia infection is linked to several complications including chorioamnionitis; premature rupture of membranes; preterm labour and birth; low birth weight; intrauterine growth reduction and postpartum endometriosis. Furthermore, infants born through infected birth canals are at risk of acquiring pneumonitis, conjunctivitis and nasopharyngeal infection.
Routine treatment for Chlamydia with doxycycline is contraindicated in pregnancy and should be avoided as long as a suitable alternative can be used. Treatment in pregnancy is recommended, with azithromycin 1 g as a single dose, considered safe and efficacious. Recent research from Muanda et al. found an association between a number of antibiotics and spontaneous abortion, however there is no current analysis describing the comparative risk of treatment versus avoiding antibiotic risk. Therefore, current BASHH guidelines do not consider it valid enough to trigger a change in treatment guidelines. Alternative regimes include:
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Erythromycin 500 mg four times a day for 7 days.
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Erythromycin 500 mg twice daily for 14 days.
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Amoxicillin 500 mg three times a day for 7 days.
Where alternatives to standard treatment with doxycycline do not exist, it is recommended that a full course (doxycycline 100 mg BD for 7 days) can be considered if the full course can be completed prior to 15 weeks’ gestation.
Patients treated for chlamydia in pregnancy are recommended to undergo a test of cure (TOC) no earlier than 3 weeks after completing treatment. Patients are advised to abstain from sexual contact and treatment of regular partners should be completed within this period to prevent reinfection.
Gonorrhoea
Gonorrhoea infection is caused by the gram-negative diplococcus Neisseria gonorrhoeae .
Prevalence of gonorrhoea infection has been on a sharp increase over the last few years, with rates of infection rising by 7.5% in 2023 compared to 2022. This number of diagnoses is the highest since records began in 1918.
Primary sites of infection are columnar epithelium-lined mucous membranes of the urethra; endocervix; rectum; pharynx and conjunctiva, with transmission occurring via direct inoculation of infected secretions from one mucous membrane to another. Concurrent infections with chlamydia, trichomoniasis, mycoplasma and candida are not uncommon and should be considered and assessed for if symptoms persist following treatment.
Female urethral infection may present with dysuria alone, whereas endocervical infection presents with increased or altered vaginal discharge in around 50% of cases.
Complicated gonococcal infection via transluminal spread can lead to PID. Furthermore, haematogenous dissemination may rarely occur leading to skin lesions; arthralgia; arthritis; and tenosynovitis.
During pregnancy, gonococcal infection increases the chance of spontaneous abortion; premature labour; early rupture of fetal membranes; perinatal mortality and gonococcal conjunctivitis in the newborn.
The methods used to diagnose gonorrhoea vary between clinical settings dependent on what services are available. In centres with immediate microscopy availability, treatment is often given following visualization of monomorphic gram-negative diplococci, caveating that confirmatory testing may be negative. Gold standard for diagnosis is via NAAT testing performed on self, or clinician, collected vulvovaginal or endocervical swabs. Vulvovaginal swabs have been demonstrated to be the most sensitive and are therefore recommended. Culture should be obtained in addition to NAAT testing for all patients with suspected or confirmed gonorrhoea infection and their sexual contacts. Culture is essential for antimicrobial susceptibility testing and supporting microbial surveillance, particularly relevent considering the rise in multi-resistant strains of gonorrhoea recorded globally.
Treatment in pregnancy is recommended as ceftriaxone 1 g intramuscularly as a single dose (as in non-pregnant people), or spectinomycin 2 g intramuscularly as a single dose. With all confirmed gonorrhoea infections, a TOC is recommended a minimum of 14 days post-treatment. Patients should be advised to avoid all sexual contact until a negative TOC is confirmed for the patient and any infected partners.
Trichomoniasis
Trichomonas vaginalis (TV) is a flagellated protozoan that infects the vagina, urethra and paraurethral glands. It is almost exclusively transmitted through sexual intercourse.
Between 10 and 50% of women are asymptomatic. Symptomatic individuals may experience vaginal discharge, vulval itching, dysuria, or offensive odour. Occasionally, lower abdominal discomfort or vulval ulceration is reported.
On examination, the classic presentation of frothy yellow discharge only occurs in 10–30% of women – discharge varies in consistency across infected individuals. Vulvitis and vaginitis are associated with trichomoniasis. Around 2% of patients have a ‘strawberry cervix’ appearance to the naked eye, with 5–15% having no visible abnormalities on examination.
TV infection is increasingly demonstrated to have detrimental outcomes in pregnancy, associated with preterm delivery and low birth weight. Infection at delivery may predispose to maternal postpartum sepsis. Some studies have demonstrated treatment during pregnancy to be associated with negative pregnancy outcomes, however other research has demonstrated no association between treatment and pre-term delivery and low birth weight.
Asymptomatic testing in pregnancy is not recommended. Testing should be performed in those reporting change in vaginal discharge or vulvitis, or found to have vulvitis and/or vaginitis on examination. Diagnosis is ideally via microscopy of ‘wet prep’ microscopy slide samples (where available), using clinician taken swabs from the posterior fornix. NAAT testing is the gold standard for diagnosis but is not universally available. Where microscopy slide samples cannot be read within 10 minutes of being taken, and TV specific NAAT is not available, standard culture swabs should be obtained.
Metronidazole 500 mg twice daily for 7 days is the recommended treatment and is considered safe throughout pregnancy. High dose regimens should be avoided in pregnancy. Patients should be advised to avoid alcohol during, and for 48 hours after, treatment course due to a possible drug–drug interaction. All regular partners should be treated simultaneously and advised to avoid sex for at least 1 week. TOC should only be performed in those who remain symptomatic after treatment, or if symptoms recur. If TOC is via NAAT, it should be performed at least 4 weeks after the start of treatment.
Syphilis
Syphilis is a multistage, multisystem disease caused by infection with the spirochete bacterium Treponema pallidum . It is highly infectious with transmission rates of 10–60% between sexual contacts. Transmission occurs via direct contact with an infected lesion or at any stage of pregnancy transplacentally. Vertical transmission is more likely in early disease when RPR titre is greater than 8. Lesions on breasts are known to lead to transmission via breastfeeding and should be discussed.
Prevalence has increased significantly in recent years, with the number of infections increasing by 9.4% from 2022 to 2023. The largest proportional rise was in the heterosexual population at 21.8%, highlighting the importance of antenatal screening in early pregnancy, offered as standard at booking appointments. In those considered at higher risk of infection during pregnancy, such as those with change in sexual partners, further testing later in pregnancy should be considered. In the most recent available data (2021–2022), 1.64/1000 women tested positive for syphilis, with 41.2% requiring treatment. Referral and management at specialist genitourinary medicine (GUM), midwifery, obstetric and paediatric MDTs is vital to ensure appropriate management and avoid fetal and maternal complications.
There is a diverse range of signs and symptoms caused by syphilis, depending on the stage of the disease and the following list is not exhaustive. Early disease (within 2 years of infection), when the condition is most infectious to others, can cause cutaneous manifestations; lymphadenopathy; muco-cutaneous lesions; hepatitis; glomerulonephritis; meningitis; and uveitis. Syphilis then enters a period of latency for up to 40 years, after which time tertiary complications can develop. Tertiary complications include cardiovascular complications, gummatous disease (granulomatous lesions of the CNS, skin and bone), and late neurological complications. Syphilis in pregnancy can lead to fetal infection later in pregnancy, which may cause polyhydramnios; miscarriage; pre-term labour; stillbirth and hydrops.
Congenital syphilis (acquired through vertical transmission) is divided into early (diagnosed within the first 2 years of infection) and late (after this point) disease. The presence of signs at the time of delivery is dependent on the duration of maternal infection and timing of treatment. Two thirds of infants are asymptomatic at birth, but most develop symptoms within the first 5 weeks. Symptoms include rash; haemorrhagic rhinitis; lymphadenopathy; hepatosplenomegaly; and skeletal abnormalities.
The complex and varied array of signs and symptoms highlights the importance of a thorough history, examination and testing in all contacts of, or suspected cases of, syphilis.
Diagnosis is mainly via serology in asymptomatic patients and screening programmes. Testing is syphilis enzyme immunoassay (EIA) antibody testing in the first instance. However, this does not differentiate between syphilis or endemic treponematoses and a positive result should always trigger further confirmatory testing. False positive results are common in pregnancy, and these can also be due to autoimmune disease, older age and injecting drug use. Quantitative RPR is essential for assessing serological activity of syphilis and allows for the differentiation between previously treated infection and new infection.
Treatment regime in pregnancy depends on the stage of disease. Most early disease cases are managed with a single dose of IM benzathine benzylpenicillin 2.4 million units (MU). When treatment is initiated in the third trimester, a second dose is recommended one week after the first, due to reduced plasma penicillin concentrations in late pregnancy. Non-penicillin alternatives include ceftriaxone, erythromycin, and azithromycin. However, due to uncertain placental penetration, treatment of the baby with penicillin at birth is recommended when macrolides are used. De-sensitization to penicillin with immediate subsequent treatment can also be considered in allergy.
Treatment may cause a Jarisch–Herxheimer reaction, as with non-pregnant individuals. Some women (40–65%) also experience uterine contractions, secondary to the development of fever, which resolve within 24 hours. Fetal heart rate decelerations are reported in about 40% of cases, however, delivery of the fetus has not been required secondary to this, according to case series. For pregnant patients with latent disease, neurosyphilis, concurrent HIV infection, or gummatous disease then alternative, extended treatment options may be required, and current guidelines should be consulted.
Following treatment, patients should avoid sexual contact of any kind until all lesions have healed and/or at least 2 weeks have passed following treatment. Follow-up serology is recommended for all at 3, 6 and 12 months to establish a confirmed serological cure via a four-fold drop in RPR/VDRL titre. Pregnant patients with ongoing risk of infection should be re-screened later in pregnancy and further treatment may be indicated if re-exposure has occurred.
Genital warts
Anogenital warts are the cutaneous manifestation of human papillomavirus (HPV) infection, with around 90% of warts at anogenital sites caused by strains 6 or 11.
Transmission is usually via sexual contact and can occur without visible warts. Of those infected with HPV 6 or 11 between 15 and 64% develop warts, with most infections not resulting in warts and resolving spontaneously within a year.
Warts are very common with an estimated annual incidence of around 0.15% of the world’s population each year. The HPV vaccination programme introduced in the UK in 2008 for girls aged 12–13, and extended to include boys in 2019, has utilized the quadrivalent vaccine (covering HPV 6/11/16/18) since 2012. This has demonstrated a marked reduction in anogenital warts in those vaccinated prior to coitarche. Vaccination has not yet been demonstrated to reduce recurrence of warts or to be in benefit in achieving clearance, so is therefore not recommended for this indication.
The occurrence and increase in size or number of genital warts in pregnancy is common due to the relative immunosuppression of pregnancy. If HPV is present at delivery, vertical transmission can occur. Although there is no current evidence to support treatment of lesions reducing transmission, treatment may be considered to reduce the viral burden to the neonate and therefore many pregnant people may opt for treatment.
Diagnosis is usually made by visually inspecting lesions, demonstrating benign epithelial lesions usually up to 5 mm in diameter. Lesions are often multiple and can take on 4 different morphological types: papular warts; flat warts; keratotic warts; and condylomata acuminata. Most are asymptomatic however itching, bleeding and pain may occasionally occur. Any atypical features should trigger urgent biopsy as wart lesions may co-exist with malignant or peri-malignant lesions.
In rare cases (4.3/100,000 births) neonatal infection with HPV 6 or 11 can lead to juvenile-onset recurrent respiratory papillomatosis (JORRP). It is recommended that pregnant individuals experiencing ano-genital warts should be reassured of the low absolute risk of significant HPV related complications in the neonate.
Warts may spontaneously resolve in the puerperium and therefore, deferral of treatment should be considered where acceptable to the patient. Ablative treatments are preferred in pregnancy with most data to support cryotherapy and laser. Self-administered topical treatments (imiquimod, podophyllotoxin, sinecatechins) usually recommended as first line are not licensed in pregnancy, having been demonstrated to be teratogenic, and should be avoided. Caesarean section has not been demonstrated to be protective and is not recommended.
There is no routine follow up required for simple anogenital warts, although, if warts are demonstrating resistance to treatment, then further review and consideration of biopsy should be considered. Contact tracing is not required for individuals presenting with anogenital warts, and partners only require treatment for HPV if symptomatic with anogenital warts.
Genital herpes
Anogenital herpes is due to infection with the herpes simplex virus type 1 (HSV-1) or type 2 (HSV-2). HSV-1 is the usual cause of orolabial herpes and now the most common cause of genital herpes in the UK. HSV-2 was historically more commonly associated with genital herpes and is more likely to cause recurrent anogenital symptoms.
Initial episodes of HSV infection are defined as primary infection when an individual has no pre-existing antibodies to either HSV-1 or HSV-2 at the time of first symptom presentation. Non-primary infection is the first episode of HSV-1 or HSV-2 with pre-existing antibodies to the other type. Recurrent episodes are when clinical symptoms recur due to reactivation of pre-existent HSV-1 or HSV-2. In clinical practice, antibody testing is not routinely recommended as many individuals are asymptomatic carriers of the virus and knowledge of infection can cause significant distress. Transmission is through direct skin to skin contact, which can occur through contact of oral lesions, infection with the genitals, or vice-versa.
Clinical features include symptoms of painful ulceration, dysuria and vaginal discharge. Primary infection is commonly associated with systemic symptoms of flu-like symptoms of fatigue, fever and myalgia. Clinical signs include blistering and ulceration of the external genitalia, perianal region and cervix. Often, there is also tender inguinal lymphadenitis, which is likely to be bilateral in the first episode, and usually unilateral for subsequent episodes. Recurrent blistering and ulceration are limited to the infected dermatome.
Complications in the mother include superinfection of lesions; autonomic neuropathy; autoinoculation of other skin sites; aseptic meningitis; and hepatitis. Disseminated skin lesions can occur, and some are associated with disseminated disease.
Neonatal herpes is a very rare but serious infection with high morbidity and mortality, with a significant burden of infection and complications on preterm infants born before 36 weeks gestation. It is classified into three subgroups depending on the site of infection: a) localized to the skin, eye and/or mouth (30% of neonatal infection); b) local CNS disease (encephalitis alone); c) disseminated infection with multi-organ involvement. Localized infection has the best prognosis, partially due to CNS and disseminated infection presenting late, often without localized eye, mouth or skin symptoms. Treatment with IV aciclovir reduces neurological and ocular morbidity (long-term effects) to less than 2%. 70% of neonatal infections have disseminated and/or CNS infection. CNS infection with antiviral treatment has 6% mortality, with disseminated disease carrying a 30% risk of mortality. Neonatal risk of HSV should be carefully assessed with investigations and treatments completed in line with current BASHH and RCOG joint guidelines with involvement of neonatal specialist teams.
In pregnancy, risks and management of infection vary depending on the stage of pregnancy and whether the infection is primary or recurrent. Factors contributing to vertical transmission are dependent on the type of maternal infection (primary/recurrent); presence of transplacental maternal neutralizing antibodies; duration of rupture of membranes before delivery; mode of delivery and use of fetal scalp electrode. The risk of transmission is greatest when a pregnant person acquires primary infection in the third trimester, particularly within 6 weeks of delivery, as viral shedding may persist, and maternal protective antibodies have yet to develop. As primary infection within 6 weeks of delivery carries a very high risk of neonatal transmission (41%), caesarean section should be recommended. There is no evidence to suggest an increased risk of spontaneous miscarriage with primary genital herpes in the first trimester.
Diagnosis is most commonly via PCR testing of swabs from symptomatic lesions, which differentiates between HSV-1 and HSV-2. This is valuable when advising patients about the likelihood of recurrences. Initial episode of HSV during pregnancy is one of the few occasions that HSV serology has a place in management. Those seronegative for the HSV type identified by lesion swab PCR are experiencing a primary infection and treatment, birth and postnatal planning should reflect this.
Treatment should not be delayed until confirmatory PCR results are available, and all first occurrence of lesions should be considered to be primary infection for the purpose of birth planning until results are available. Aciclovir, and the second line alternative valaciclovir, are considered safe throughout pregnancy, although off license, and reduces the length and severity of outbreaks when taken episodically (Aciclovir 400 mg TDS for 5 days). Suppression therapy with daily antivirals (Aciclovir 400 mg TDS) helps to reduce recurrences and should be routinely offered from 32 weeks to all pregnant people with a history of HSV and from 28 weeks to those considered high risk of premature delivery. Symptomatic management advice includes saline bathing, analgesia and topical anaesthetic agents such as lidocaine 5% ointment. Counselling is also essential in reducing distress in patients, with clear explanation of the high prevalence, and signposting to support organizations, improving adjustment and quality of life. In serodiscordant couples, suppressive therapy may be considered for non-pregnant partners to reduce the risk of transmission during pregnancy. Furthermore, some pregnant people may choose to be abstinent in the third trimester to reduce transmission at a time when acquisition of HSV would lead to increased risk of peripartum transmission to the infant. Guidance suggests patients with a known history of HSV under midwife led care, initial episode of HSV during pregnancy or herpetic lesions present at delivery, should have a specific HSV delivery and postnatal plan formulated through multidisciplinary collaboration between GUM, neonatal and obstetric teams.
Mycoplasma genitalium
Mycoplasma genitalium (M. Gen) is a relatively new and emerging sexually transmitted infection which was first isolated in 1981. It is the smallest known self-replicating bacterium.
Prevalence is estimated to be between 1 and 2% for both men and women in the general population, with sexual health clinic attendees having higher rates of prevalence between 4 and 38%. Infection can occur at urethral, vaginal and rectal sites with sexual transmission between partners. There are high rates of co-infection with other STIs so all patients should be offered a full sexual health screen at diagnosis.
The majority of patients are asymptomatic. In females, symptoms tend to be non-specific, with the most common being post-coital bleeding. Other symptoms and complications include dysuria; painful inter-menstrual bleeding; cervicitis; endometritis and PID. Infection in pregnancy is associated with a small increased risk of pre-term birth and spontaneous abortion.
As colonization with M. Gen is not thought to cause disease in most people, screening asymptomatic patients is not recommended. Currently, testing is recommended in patients with signs and symptoms of PID and mucopurulent cervicitis. Current sexual partners of those with confirmed M. Gen should be offered testing and/or offered epidemiological treatment.
Diagnosis is via NAAT which detects M. Gen specific DNA or RNA. Some laboratories will also offer resistance testing through susceptibility genotyping and, where available, this is recommended. Vuvlovaginal swabs are the most sensitive, followed by endocervical samples.
When treatment is indicated, patients should be advised to abstain from sex until 14 days after the start of treatment. Treatment is recommended based on macrolide resistance. Doxycycline is the standard treatment for uncomplicated disease in the absence of macrolide resistance. This is unsafe during pregnancy, affecting bone and teeth development. The recommended treatment for complicated infection, moxifloxacin, is also contraindicated in pregnancy. Azithromycin is the recommended treatment in pregnancy, using a 3-day course of 1 g on day one, followed by 500 mg each day for 2 days. In cases of macrolide resistance, options for pregnant individuals are limited. Where possible, treatment should be delayed until after pregnancy. It is essential to give pregnant people all available information, including lack of evidence to predict safety of alternative regimes like pristinamycin in pregnancy, and possible adverse effects of suggested regimes.
Following treatment all patients with confirmed M. Gen require a test of cure 5 weeks after the start of treatment, when risk of reinfection should be excluded and compliance with medication verified.
Hepatitides
Hepatitis A, B and C viruses (HAV, HBV, HCV) are all viral infections which cause inflammation of the liver and, in chronic infection, cirrhosis. HAV is usually transmitted through the feacal-oral route while HBV and HCV are most commonly transmitted through blood. Sexual transmission of all 3 can occur, with partners of those with confirmed infection requiring immediate screening and further testing following a 3-month window period. At risk groups include people who inject drugs; post-sexual assault; sex workers; men who have sex with men; and their partners. Up to half of adults are asymptomatic even in the acute stages. Those experiencing symptoms may have a prodromal flu-like illness with right upper quadrant abdominal pain followed by an icteric illness characterized by jaundice, anorexia, fatigue, dark urine and light stools. Testing is through serology, with HBV testing routinely part of the national pregnancy screening programme.
HAV is a transient infection which resolves naturally without treatment. Similarly, HBV infection in immunocompetent adults rarely develops into chronic infection. Those infected with HBV in childhood, or by vertical transmission, are more likely to acquire chronic infection. HCV usually requires treatment with antiviral medication to achieve viral clearance, however these are not recommended in pregnancy and should be avoided due to teratogenicity. HAV, HBV and HCV in pregnancy can increase the risk of miscarriage and pre-term labour, proportional to the severity of the illness. There are no known teratogenic effects. There have been case reports of vertical transmission in HAV, and the risk of vertical transmission is higher for HBV depending on the stage and severity of infection. Patients with HCV should also be warned there is a small risk of vertical transmission.
Conclusion
Sexually transmitted infections (STIs) can have significant impacts and consequences for both the pregnant person and the fetus. STIs may increase the risk of various malignancies, increase the risk of HIV acquisition, and are associated with significant stigma. Risk assessments should be carried out at every antenatal appointment, with a sexual health history taken if necessary, and STI screening offered. When interpreting results of STI screening tests, window periods should be taken into consideration and repeat testing offered outside the window period, if required. Management of STIs can differ during pregnancy, and so ideally should be undertaken via a coordinated MDT approach between obstetricians, GUM physicians, and paediatricians. It should be remembered that if an individual is diagnosed with one STI they are more likely to have another, and so should be offered testing for all STIs, including HIV, in this instance.
