Recurrent Pregnancy Loss and Infertility

Recurrent pregnancy loss and infertility are reproductive problems for which genetic evaluation and counseling are often part of the workup. From a genetics standpoint, attention centers on parental chromosomal rearrangements, fetal aneuploidy as a cause of loss, and inherited factors that can affect fertility, together with the supportive counseling these findings require.

Definition

Recurrent pregnancy loss is conventionally defined as the loss of two or more pregnancies, and infertility as the failure to achieve pregnancy after a defined period of regular unprotected intercourse; both can prompt genetic evaluation and counseling to identify heritable or chromosomal contributors.

Scope

This topic frames recurrent pregnancy loss and infertility as reference subjects within reproductive genetics: their working definitions, the genetic contributions investigated (such as balanced parental translocations and embryonic aneuploidy), and the role of counseling in interpreting results. It is descriptive background and does not prescribe an evaluation or treatment pathway.

Core questions

• How are recurrent pregnancy loss and infertility defined for the purpose of evaluation?
• What genetic factors, such as parental chromosomal rearrangements, are investigated?
• How are genetic findings interpreted and communicated in counseling?

Key concepts

• Definition thresholds for recurrent loss and infertility
• Parental balanced translocation
• Embryonic aneuploidy as a cause of loss
• Karyotyping of products of conception
• Recurrence risk after a chromosomal finding
• Counseling under diagnostic uncertainty

Mechanisms

A substantial proportion of sporadic early pregnancy losses are due to embryonic chromosomal aneuploidy, often arising de novo. In a minority of couples with recurrent loss, one partner carries a balanced structural chromosomal rearrangement (such as a reciprocal or Robertsonian translocation) that can produce unbalanced gametes and increase the chance of loss. Genetic evaluation - parental karyotyping and, where appropriate, analysis of products of conception - aims to distinguish these mechanisms, which carry different recurrence risks and counseling implications. For infertility, evaluation may include karyotype and specific gene testing depending on the clinical picture.

Clinical relevance

This entry explains how genetic factors in recurrent loss and infertility are investigated and why the results matter for counseling about recurrence; it is descriptive background to support understanding of the evidence, not individualized advice. Evaluation and management decisions are made by clinicians with the couple, and most guidelines note that the available evidence for many interventions is limited.

Epidemiology

Recurrent pregnancy loss affects a small percentage of couples trying to conceive. Across all clinically recognized pregnancies, chromosomal abnormality is a leading cause of early loss, whereas an identifiable parental chromosomal rearrangement is found in only a minority of couples with recurrent loss.

Evidence & guidelines

The ESHRE guideline on recurrent pregnancy loss and ASRM committee opinions provide consensus definitions and outline evaluation, while noting that much of the underlying evidence is of low to very low quality. These documents anchor how the conditions are defined and how genetic findings are framed in counseling.

History

Genetic evaluation of reproductive failure developed alongside clinical cytogenetics, which made parental karyotyping feasible and clarified the role of chromosomal rearrangements and embryonic aneuploidy. Successive professional definitions have refined the thresholds used to trigger evaluation for both recurrent loss and infertility.

Debates

Defining recurrent pregnancy loss

Whether the threshold should be two or three losses, and whether non-consecutive or biochemical losses count, varies between professional bodies, which affects who is evaluated and counseled.

Seminal works

• eshre-2018-rpl
• asrm-2013-definitions

Frequently asked questions

Why is parental karyotyping sometimes done after recurrent pregnancy loss?

A small proportion of couples with recurrent loss have a balanced chromosomal rearrangement in one partner that can lead to unbalanced embryos; identifying it informs counseling about recurrence risk and reproductive options.

Is most early pregnancy loss caused by an inherited problem?

No. Many sporadic early losses result from chromosomal errors arising in the individual pregnancy rather than from an inherited condition; an identifiable parental genetic cause is found only in a minority of couples with recurrent loss.