Article produced in association with London Pregnancy Clinic and Jeen Health

For the majority of couples planning a pregnancy, genetic testing is not something they think about until a problem arises.

Pre-conception genetic carrier screening challenges this approach by identifying risk before pregnancy begins.

As panel sizes have grown and at-home testing options have become widely available, carrier screening is transitioning from a niche clinical referral into a mainstream component of reproductive planning.

What Carrier Screening Tests For

Being a carrier of a genetic condition means carrying one copy of a variant in a gene associated with that condition, without being affected by it.

In most cases, carriers are entirely unaware of their status.

The clinical significance of carrier status emerges when both members of a couple carry a variant in the same gene: in this scenario, each pregnancy carries a one in four chance of resulting in a child who inherits two copies of the variant and is affected by the condition.

The conditions most frequently included in expanded carrier screening panels include cystic fibrosis, spinal muscular atrophy (SMA), fragile X syndrome, sickle cell disease, and a range of metabolic and enzyme deficiency disorders.

The Beacon 787 carrier test, offered by Jeen Health, screens for 787 conditions from a single sample, making it one of the most comprehensive panels currently available to UK families.

Who Is Most Likely to Benefit

Any couple planning a pregnancy can consider carrier screening. It is particularly relevant for:

• Couples with a family history of a known inherited condition
• Those from populations with higher carrier frequencies for specific conditions, including Ashkenazi Jewish, South Asian and African communities
• Couples pursuing fertility treatment, where genetic information informs treatment planning
• Those who wish to have the most complete picture of their reproductive health before conception

Importantly, being a carrier of a condition does not mean a child will be affected. It means there is a defined statistical risk that can be quantified, discussed and planned for with appropriate clinical support.

How the Test Is Performed

Carrier screening is typically carried out on a blood or saliva sample.

For at-home options such as the testing offered by Jeen Health, a cheek swab collection kit is dispatched to the patient, the sample is returned by post, and results are delivered digitally within a defined turnaround period.

In-clinic carrier testing may use a blood draw and provides the advantage of immediate access to a clinical consultation at the point of result delivery.

London Pregnancy Clinic offers genetics counselling through its partnership with Jeen Health, allowing couples to receive and contextualise carrier test results with expert support.

Genetic counselling before and after testing is recommended by Genomics England as a standard component of any genomic testing pathway.

What Happens If Both Partners Are Carriers

If both partners are identified as carriers for the same autosomal recessive condition, they are typically offered further counselling to discuss their options.

These may include proceeding naturally with an awareness of the risk, using prenatal diagnosis (CVS or amniocentesis) during pregnancy to test the fetus, or pursuing preimplantation genetic testing (PGT) in the context of IVF, which allows unaffected embryos to be selected before transfer.

The purpose of identifying carrier status before pregnancy is to give couples time to consider these options without the added pressure of an ongoing pregnancy.

Knowledge of carrier status does not remove reproductive choices; it expands the information available when making them.

The Role of Pre-Conception Services

Carrier screening sits within a broader category of pre-conception care that includes fertility assessments, general health optimisation and, where relevant, management of existing conditions before pregnancy begins.

London Pregnancy Clinic offers pre-conception services encompassing fertility investigations, genetics counselling and carrier testing as part of an integrated 0th trimester approach, allowing couples to address genetic and clinical risk factors before their pregnancy starts rather than after.

Disclaimer: This article is produced for informational purposes only and does not constitute medical advice, diagnosis or treatment.

Clinical guidance referenced reflects published NHS, NICE and RCOG standards as at March 2026. Individual circumstances vary; readers are advised to consult a qualified healthcare professional before acting on any information in this article.

This piece was produced in association with London Pregnancy Clinic and Jeen Health, which provided background clinical information for editorial purposes.

Hyperlinks to external sources are included for reference only and do not represent an endorsement of any product, service or organisation.

Article produced in association with London Pregnancy Clinic and Jeen Health

For many years, formal clinical involvement in a pregnancy began at the point of confirmation, typically around eight to ten weeks.

The concept of the ‘0th trimester’ represents a shift in thinking: that the period before conception is itself a clinically significant window, during which health optimisation, risk identification and informed planning can meaningfully improve pregnancy outcomes.

Guidance from Tommy’s and the NHS both recommend pre-conception care as part of responsible reproductive health management.

What Pre-Conception Care Involves

Pre-conception care is not a single test or appointment. It is a structured approach to assessing and optimising a woman’s health before she attempts to conceive.

The NHS guidance on planning a pregnancy recommends a range of measures including taking folic acid, reviewing medications for safety in pregnancy, ensuring immunity to rubella and chickenpox, and addressing pre-existing conditions such as thyroid disorders, diabetes or high blood pressure before conception occurs.

General pre-conception assessments typically include blood pressure and BMI review, full blood count and iron levels, thyroid function, immunity screening (rubella, varicella), vitamin D status and cervical screening if overdue.

For women with existing conditions, specialist review before pregnancy is often more valuable than specialist referral during it.

Fertility Investigations as Part of the 0th Trimester

For women who are planning a pregnancy but have concerns about fertility, pre-conception investigations provide information that informs planning rather than leaving uncertainty unaddressed.

Clinics offering 0th trimester services, including London Pregnancy Clinic, provide investigations including hysterosalpingo-contrast-sonography (HyCoSy) to assess tubal patency, follicle tracking scans, anti-Mullerian hormone (AMH) testing to estimate ovarian reserve, and endometrial assessment.

These tests do not guarantee conception but they provide a clinical foundation from which fertility decisions can be made with better information.

Genetic Assessment in Pre-Conception Care

The genetic dimension of pre-conception care is increasingly central to a thorough 0th trimester assessment.

Genetic carrier screening before pregnancy allows couples to identify their carrier status for conditions such as cystic fibrosis, SMA and a range of other inherited disorders before conception, giving them time to consider their options with appropriate clinical support.

At-home carrier testing offered by Jeen Health provides access to comprehensive carrier screening without the need for a clinical referral.

Couples collect their sample at home and receive results within a defined timeframe.

When both partners carry a variant in the same gene, the result can be followed up with genetic counselling via clinics such as London Pregnancy Clinic, where clinical specialists can contextualise the findings and explain the available options.

Lifestyle and Nutritional Factors

Pre-conception health is not limited to clinical testing.

Lifestyle factors including physical activity levels, nutritional status, alcohol consumption and smoking all influence fertility and early fetal development.

Pre-conception care provides an opportunity to address these factors proactively rather than as an afterthought following a positive test.

Folic acid supplementation, recommended at 400 micrograms per day in the pre-conception period and the first trimester, is one of the most evidence-supported interventions available.

Why Timing Matters

Many of the interventions that benefit pregnancy are most effective when started before conception rather than after.

Addressing thyroid dysfunction, normalising blood pressure, treating iron deficiency anaemia, and identifying genetic risks all have a higher potential impact when managed from the outset rather than detected at the first antenatal appointment.

The 0th trimester framework provides a way of thinking about pre-conception care as a structured medical period with its own clinical agenda, rather than simply a waiting room for the first trimester.

What a Pre-Conception Appointment Might Look Like

A comprehensive pre-conception assessment with a specialist provider would typically cover a clinical consultation reviewing medical and family history, a pelvic ultrasound scan, blood tests for general health markers and fertility hormones, cervical health review if indicated, and a discussion of genetic risk including a recommendation for carrier screening if appropriate.

For couples with specific concerns about fertility or genetic history, specialist investigations can be added to this baseline assessment.

Disclaimer: This article is produced for informational purposes only and does not constitute medical advice, diagnosis or treatment.

Clinical guidance referenced reflects published NHS, NICE and RCOG standards as at March 2026. Individual circumstances vary; readers are advised to consult a qualified healthcare professional before acting on any information in this article.

This piece was produced in association with London Pregnancy Clinic and Jeen Health, which provided background clinical information for editorial purposes.

Hyperlinks to external sources are included for reference only and do not represent an endorsement of any product, service or organisation.