Possible CMV transmission via intrauterine insemination: case report

Abstract

Background

Maternal cytomegalovirus (CMV) infection at conception can cause congenital CMV (cCMV) infection and substantial morbidity. Although CMV screening is mandated for sperm donors, the risk of acquiring CMV from donor sperm is unknown. Experience with HIV may lead clinicians to expect that standard sperm-washing reduces CMV transmission risk for procedures including intrauterine insemination. However, limited data suggests that CMV may differ importantly from other herpesviruses and from HIV after sperm washing.

Case Presentation

A 29-year-old CMV immunoglobulin (Ig)M- and IgG-negative patient underwent intrauterine insemination with a directed donor. The donor was CMV IgM-negative and IgG-positive at the time of donation but had been serum IgM-positive 128 days before donation, and urine CMV PCR-positive 107 days before donation. Following intrauterine insemination, the patient developed clinical evidence of acute CMV infection, CMV viremia, and positive CMV IgM and IgG. The intrauterine insemination did not result in pregnancy. No sources of CMV transmission other than intrauterine insemination could be identified.

Conclusions

Because screening and prevention options for perinatal CMV transmission are limited, a systematic research agenda to understand and reduce CMV transmission risk from seropositive sperm donors is needed to create clear guidelines for fertility treatments and support shared decision-making. Novel approaches to lower risk of transmission from sperm donors with detectable CMV IgG should also be further evaluated. These might include CMV DNA testing of washed sperm samples prior to fertility treatments, antiviral therapy prior to semen collection and/or CMV PCR or IgM screening in pregnant patients who conceived using sperm from antibody-positive donors.

Background

Cytomegalovirus (CMV) causes mild illness in most immunocompetent adults, but infection during pregnancy can lead to congenital CMV (cCMV) [1]. Due to the high incidence of CMV during pregnancy (0.65% in high-income countries) [2], cCMV and related child morbidity are common [1]. At birth, cCMV may manifest as petechial rash, jaundice, hepatosplenomegaly, microcephaly, lethargy, chorioretinitis, or optic atrophy [3]. Long-term complications can include developmental delay, vision impairment, and progressive hearing loss; cCMV is the leading nongenetic cause of sensorineural hearing loss worldwide [1, 3].

Data on risk of intended parents, and their neonates, acquiring CMV through sperm donation are limited. Although the US Food and Drug Administration (FDA) mandates CMV screening and testing for sperm donors and the American Society for Reproductive Medicine also suggests recipient (and partner) testing [4, 5], the risk of acquiring CMV through sperm donation is unknown. Older literature suggests that cryopreserved semen from immunoglobulin (Ig)G-positive donors may have PCR-detectable virus in 8.1%, and replication-competent (presumed infectious) virus in 4.5% [6]. Initially seronegative semen donors may also seroconvert during quarantine periods [7]. However, clinicians familiar with assisted reproduction in the context of HIV or non-CMV herpesviruses may anticipate that standard sperm-washing techniques substantially reduce infectious CMV virus and transmission risk [8]. Here, we present the case of a CMV-seronegative intended parent who may have acquired a primary CMV infection from donor sperm during intrauterine insemination (IUI) despite standard screening and sperm washing processes. This case is an important reminder of this risk and a call for additional research to optimize guidelines regarding CMV IgG-positive sperm donors.

Case presentation

A 29-year-old woman presented for reproductive care and opted for intrauterine insemination (IUI) with a directed sperm donor. Baseline laboratory testing for the intended parent including endocrine markers, complete blood count, sexually transmitted disease screening, and immunization titers were within normal ranges. The intended parent worked in healthcare but had minimal physical contact with patients and consistently wore a facemask due to then-current COVID-19 guidelines. She also had no contact with small children. Sera from both the patient and her partner were tested for CMV immunoglobulin (Ig)G and IgM; these were undetectable prior to insemination. CMV viral load testing for the patient was performed using the Cobas CMV test (Roche Molecular Systems) with the Cobas 6800 system. CMV antibody testing for the patient was performed at Quest Diagnostics, San Juan Capistrano.

Sperm donor blood samples were screened using a standard testing battery. The manufacturers and techniques used for donor testing are not available, as this testing was done outside our system. Donor serum tests for CMV IgG and IgM were positive and indeterminate (IgM 34.7 IU/mL; indeterminate range 30.0-34.9 IU/mL), respectively, on the first pre-donation screening date. A second serum sample 21 days later tested CMV IgG-positive and IgM-negative (22 IU/mL); qualitative urine PCR ordered in follow-up to the detected IgM that day was positive.

The intended parent was referred to a perinatal infectious disease specialist to discuss the possibility of acquiring CMV from the donor and risk of cCMV. Because donor IgM had then become negative (suggesting the donor’s primary infection was at least several months prior), the risk of CMV transmission was thought to be low. Consistent with ASRM guidelines, given the urine PCR positivity of the donor, the intended parent was advised to discard the stored semen sample and repeat donor serum and urine testing and semen collection in three months [5].

Three months later, a new semen sample was collected. On the day of collection, donor serum CMV IgG was positive, and IgM was negative; despite recommendations, urine was not tested for CMV at that time. The sample underwent standard sperm washing per the sperm bank protocol and was stored for per-protocol quarantine of at least 6 months. The patient elected to delay further, and 17 months after semen collection, the intended parent again tested serum-negative for CMV IgG and IgM, and underwent IUI with the previously cryopreserved semen sample from the second donation (Day 0, Fig. 1).

Fig. 1.

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On day 13 after IUI, she developed fever, followed by headache, myalgias, chills, and night sweats. On day 17, serum testing for CMV revealed detectable CMV DNA (< 200 copies/mL). On day 19, she remained symptomatic; physical exam was unremarkable. Serum CMV DNA was then detectable (260 copies/mL). Additional laboratory evaluation revealed leukopenia with a white blood cell (WBC) count of 3.9 K/uL, with 12.3% reactive lymphocytes. Aspartate transaminase (AST) and alanine transaminase (ALT) were elevated at 93 and 110 U/L, respectively (Fig. 1). Alkaline phosphatase (100 U/L) and bilirubin (0.5 mg/dL) were normal. Lactate dehydrogenase was elevated (394 U/L). Serologic tests were consistent with remote Epstein-Barr virus infection and negative for Lyme disease. Serum PCR tests for ehrlichiosis and anaplasmosis were negative. Blood cultures demonstrated no growth. Nasopharyngeal SARS-CoV-2 PCR was negative on multiple occasions across days 14–19. On day 23, serum CMV IgM and IgG were newly detectable, and CMV viremia peaked (921 copies/mL). CMV IgG Ab avidity was low (0.40), consistent with recent infection. Viremia declined to 829 copies/mL on day 32 and to < 35 copies/mL on day 89.

The IUI procedure did not result in pregnancy. The intended parent was symptomatic for 4 weeks and then recovered completely. WBC count, and AST and ALT normalized by days 23 and 42, respectively. The intended parent’s serum tested positive for CMV IgG and equivocal for IgM on day 77; serum IgM was undetectable on day 122. The intended parent’s fever, leukopenia with atypical lymphocytes, elevated transaminases, and CMV antibodies and viremia were thought to be consistent with acute CMV infection. After thorough investigation of possible exposures, no clear sources of CMV transmission other than IUI were identified.

The intended parent was counseled on residual cCMV risk with recent maternal primary infection and advised to wait three months before additional fertility treatments. She underwent in vitro fertilization (IVF) with a new sperm sample from the same donor on day 336. She was followed closely during pregnancy and delivered a healthy baby on day 596 with no evidence of cCMV. The patient provided written permission to publish this case.

Discussion

We report an acute CMV infection following IUI using sperm from a donor with CMV IgG-positive and IgM-negative serum, which raises sufficient concern about IUI as the mechanism of CMV transmission that clinicians and patients should be counseled about this possibility. If the IUI had been successful, the fetus may have been at risk for cCMV, which confers a high risk of adverse health outcomes. This case raises several important issues.

First, current FDA guidelines for CMV screening in fertility treatments may inadvertently exclude low-risk sperm donors and include higher-risk donors. For anonymous sperm donors, the FDA requires medical record screening to assess risk of infectious diseases, followed by blood and urine testing for HIV, hepatitis B and C viruses, Treponema pallidum (syphilis), Chlamydia trachomatis, Neisseria gonorrhea, human T-lymphotropic virus (HTLV), and CMV within seven days of donation [4]. At most commercial sperm banks, semen is then quarantined for at least six months, followed by retesting of the donor for infectious diseases [4]. If all tests are negative at both time points, the quarantined semen is released for use. For directed (known) donors, the FDA requires infectious disease testing for the donor within seven days of semen collection [4]. More recent recommendations from the American Society for Reproductive Medicine recommends a sperm quarantine process of > 35 days followed by repeat infectious diseases screening; these guidelines do not endorse the use of fresh sperm donation without quarantine and infectious diseases screening before release of sperm for use [5]. Additionally, sperm banks may independently require quarantining and retesting for directed donors [5, 9]. FDA guidelines dictate that the physician responsible for a sperm donor with detectable total CMV antibody (reflecting IgG or IgM) must be notified and have the positive screening test documented, but no additional testing or restrictions are required [4]. Many CMV IgG-positive donors were likely infected years prior to donation; excluding all donors with detectable IgG would exclude many who pose minimal risk of CMV transmission. Conversely, donors without detectable CMV IgM or IgG due to a very recent primary infection may still have infectious virus in semen and may pose some risk to recipients, which emphasizes the need for a quarantine period and retesting [7, 10]. We suspect the donor in the current case likely had infectious virus in his semen based on the timing of CMV infection after IUI in the intended parent.

Second, the impact of standard sperm washing (performed for all samples used for IUI, IVF, and ICSI) in reducing CMV transmission risk during fertility treatment is unknown. Before washing, between 2 and 62% of unselected semen samples from donors experiencing infertility and/or seeking fertility evaluation and treatment have been observed to contain CMV DNA, reflecting wide variation in studied populations [8, 11]. Unlike HIV and other common viruses, CMV can infect immature spermatocytes and remain inside developing mature spermatozoa; immunohistochemistry staining reveals CMV within spermatozoa head, tail, and body and adherent to cell membranes [11, 12]. While standard sperm washing decreases the concentration of both free virus in semen and virus-containing somatic cells (white blood cells and epithelial cells), it is less effective at removing CMV than at removing other viruses that primarily survive within WBCs or free in semen [13]. In one study of semen samples with detectable herpesvirus DNA prior to undergoing the PureSperm (twice-centrifuged) washing procedure, human herpesvirus (HHV)-6 and HHV-7 were not detected after washing, but herpes simplex virus (HSV) and CMV DNA remained in 59% and 89% of samples, respectively [8]. Although previously offered for HIV, nucleic acid testing after sperm washing and prior to sample use for assisted reproduction is not widely available for other viruses, including CMV [13]. The effectiveness of standard sperm washing for CMV removal thus remains largely unknown.

Third, little is known about the impact of cryobanking on the viability of infectious CMV virus. Infectious virus can be recovered by culture of semen for < 5% of CMV IgG-positive men [14]. Older literature from the 1980s and 1990s reveals that CMV can survive semen cryopreservation and storage in liquid nitrogen for at least nine months [15]. These older studies also report that infectious CMV was detected by cell culture in 4.5% of cryopreserved semen samples and by CMV PCR in 8.1% of cryopreserved samples from seropositive donors [6]. However, CMV is difficult to grow in culture, and technology to accurately quantify infectious virus is limited, so culture results may underrepresent infectious virus in sperm samples [16]. Furthermore, there is limited information on whether viable CMV virus is present in cryopreserved semen samples when using modern sperm washing techniques.

Lastly, the absolute risks of CMV transmission to a patient attempting pregnancy with a sperm donor and the degree to which these risks vary by donor serostatus, donor serum and urine PCR positivity, and type of fertility treatment (e.g., IUI, IVF, or ICSI) are unknown. In theory, CMV transmission risk with IVF and ICSI may be lower than with IUI due to use of individual spermatozoa and introduction of spermatozoa only in vitro; however, there are no data to quantify the relative risk of by type of fertility treatment. In this case, CMV transmission risk from the donor was considered low because donor IgM had become undetectable; however, donor urine was not tested (as recommended) at the time of repeat semen collection. Whether CMV persists in urine, testes, and semen after serum IgM clearance, and whether urine PCR positivity is a reasonable proxy for semen viral presence, are largely unknown. For intended parents, their own CMV serostatus likely also impacts CMV acquisition and cCMV risk. Although more than 80% of people of childbearing potential in some US regions and demographic groups are CMV seropositive, they remain at risk for reinfection (non-primary infection), which may confer a lower transmission rate to the fetus but a similar risk of severe cCMV fetal outcomes, and remains an important cause of pediatric hearing loss [1, 17–19]. The remainder (CMV seronegative patients) are at risk for primary infection, with a higher risk of transmission to the fetus and high risk of severe cCMV fetal outcomes [1, 18, 19].

The primary limitation to our case report is the inability to confirm that the CMV strain present in the donor semen was identical to the CMV strain causing acute infection in the patient receiving fertility treatment. However, key strengths of this report include plausible CMV exposure for the patient undergoing fertility treatment, very few other exposures due to Covid-19-associated precautions at the time, and a timeline of symptoms and resolution that is consistent with acute CMV infection immediately following IUI.

Although effective treatments are emerging to prevent CMV transmission to fetuses and reduce the severity of fetal infection, screening for incident CMV infection in pregnant patients is not routinely recommended in the United States, and thus opportunities for antiviral therapy are often missed [10, 20–22]. Therefore, preventing CMV acquisition during pregnancy, including transmission via fertility treatments, is critical. We do not advocate for excluding all CMV IgG-positive donors, as this would exclude many donors with minimal risk of transmission, reduce already-limited donor availability, and widen racial and sexual orientation-based disparities in access to assisted reproduction [14, 15, 23–26]. However, a systematic research agenda is needed to better understand and reduce risks of CMV transmission from seropositive sperm donors for each type of fertility treatment, create clear guidelines, and support informed consent and shared decision-making. For example, approaches that may reduce risk and deserve further study include: CMV DNA PCR testing of washed sperm samples, with use of PCR-negative samples for assisted reproduction; gaining additional data about the risk of current infectiousness by measuring CMV IgG avidity or urine CMV DNA PCR in IgG-positive donors (with use of sperm samples only from donors with high IgG avidity and/or undetectable urine PCR); or treating IgG-positive sperm donors with antiviral medications prior to sperm donation, which has been shown to reduce HSV in sperm samples [1, 8, 13].

Although antibody screening in pregnancy confers risk for both false-positive and false-negative results, there may also be an important role for CMV screening with IgM/IgG or PCR after conception in people who become pregnant using sperm from IgG-positive donors, even in settings where routine screening of all pregnant patients is not yet recommended. This approach might identify treatment-eligible maternal periconception primary infections and offer opportunities to detect and treat fetal infection antenatally. It would also identify infants in need of virologic testing at birth, permitting both antiviral treatment and long-term follow-up for CMV sequelae including hearing loss, for which early detection and intervention markedly improve outcomes. The clinical- and cost-effectiveness of these strategies are unknown. While awaiting more research, all individuals desiring pregnancy should be informed of the risk of maternal CMV infection and available preventative measures.

Conclusions

Because screening and prevention options for perinatal CMV transmission are limited, a systematic research agenda to understand and reduce CMV transmission risk from seropositive sperm donors is needed to create clear guidelines for fertility treatments and support shared decision-making. Novel approaches to reduce risk of transmission from sperm donors with detectable CMV IgG should also be further evaluated. These might include CMV DNA testing of washed sperm samples prior to fertility treatments, additional donor testing with urine PCR or IgG avidity assays, donor antiviral therapy prior to semen collection, and/or CMV PCR or IgM screening in pregnant patients who conceived using sperm from antibody-positive donors.

Abbreviations

CMV

Cytomegalovirus

CMV cCMV

Congenital

FDA

US Food and Drug Administratio

Ig

Immunoglobulin

IUI

Intrauterine insemination

WBC

White blood cell

AST

Aspartate transaminase

ALT

Alanine transaminase

IVF

In vitro fertilization

HTLV

Human T-lymphotropic virus

HHV-6

Human herpesvirus 6

HHV-7

Human herpesvirus 7

HSV

Herpes simplex virus

Author contributions

AC, ID, and JA analyzed and interpreted the patient data regarding the fertility treatment and laboratory testing for infectious diseases, including CMV. ES wrote the manuscript along with LMB and AC. All authors made critical manuscript edits and read and approved the final manuscript.

Funding

This work is unfunded.

Data availability

Data supporting the results reported in the article can be obtained from the authors on reasonable request.

Declarations

Ethics approval and consent to participate

Not applicable.

Consent for publication

The patient’s written consent was obtained to publish this case report. The design of the work conforms to standards currently applied in the country of origin (United States of America), in accordance with the ethical standards of the Helsinki Declaration of 1964 as amended in 2008.

Competing interests

The authors declare no competing interests.