Why BV Keeps Returning—and Why It Matters Before Conception or Embryo Transfer

BV is still the term most women are given, but clinically it is becoming an increasingly limited way to describe what is happening. I prefer to think in terms of a dysbiotic vaginal microbiome: a microbial community that has moved away from its protective pattern and is no longer stable.

That community may contain bacteria classically associated with bacterial vaginosis, organisms linked with aerobic vaginitis, fungi, or a combination of these. This is why the first question is not simply, ‘Why has my BV come back?’ It is: How was BV identified, what was actually tested, and which microbial pattern is present now?

What recurrent BV really means

Recurrent BV is not defined well by symptoms alone. It is a repeated dysbiotic pattern that returns or persists after treatment, often because the wider microbial community has not been restored.

Earlier in my work with reproductive microbiomes, around ten years ago, symptom charts were extremely popular. They attempted to match a particular smell, discharge or sensation to a particular diagnosis. In practice, these patterns are too arbitrary to tell us reliably which organisms are present. Some women have marked symptoms with a relatively limited finding; others have significant dysbiosis without obvious symptoms.

I use symptoms as additional context after testing. They help us understand how the finding is behaving in that individual woman, but they do not replace proper microbiome assessment.

Why one vaginal result may not be enough

Before natural conception, IVF or embryo transfer, I need to understand more than whether a vaginal report contains the word ‘BV’. In recurrent cases, I test the vaginal microbiome properly and compare it with the uterine microbiome. These are connected environments, but they are not identical, and a vaginal sample cannot tell us everything that is happening at uterine level.

The comparison helps us see whether the dysbiotic pattern is limited to one site, whether similar organisms appear in both samples and what needs to be addressed before the next reproductive step.

Outside fertility work, the immediate priority may be symptom relief. Before conception or embryo transfer, the priority is the complete reproductive microbial environment and whether it is sufficiently stable to support the next stage.

What I review

I look at the sequence across time rather than one isolated result:

• where the original BV diagnosis came from and what that test could actually detect;
• the vaginal and uterine microbiome results, read together rather than as interchangeable samples;
• what changed after every treatment and what returned afterwards;
• whether Lactobacillus recovered, whether Bifidobacterium is present and which species dominate the community;
• the total microbial picture, not simply a percentage chart;
• whether the test provides sufficiently detailed fungal analysis;
• urinary changes and bowel changes alongside the reproductive findings;
• relationships with sex, menstruation, hormones and previous antimicrobial treatment;
• the partner’s seminal and reproductive microbial picture; and
• whether there is enough time to treat, restore and retest before conception or embryo transfer.

The partner must be tested

If recurrent vaginal dysbiosis is part of the fertility history, I test the partner. Repeatedly treating the woman while leaving the male reproductive microbial picture unexamined gives us an incomplete investigation. The Male Fertility section explains why the male side needs its own assessment rather than being treated as an optional addition.

The aim is not to sterilise the vagina or uterus. It is to understand the community at species level, identify what repeatedly destabilises it and check whether a protective pattern has actually been restored. A single course of treatment may reduce part of the problem without changing the conditions that allowed the dysbiosis to return.

If you have been told that BV keeps returning while you are preparing for pregnancy or IVF, you may first want to familiarise yourself with my methodology. You can then book an Introductory Fertility Review. I will review how the diagnosis was made, the vaginal and uterine findings, what happened after treatment and the partner’s results, then decide what needs to be clarified before the next fertility step.

Source starting points: Bradshaw et al.; Muzny et al..