In a study published in Human Reproduction, scientists have unveiled data challenging the traditional view on natural conception in women who have previously given birth via assisted reproductive technology (ART), such as in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI).

Led by Dr. Annette Thwaites, the study systematically reviewed and analyzed data from various sources to assess the proportion of women experiencing natural conception after an ART-aided live birth. The research suggests that natural conception may occur in at least one in five women after having a baby via ART, a number significantly higher than widely anticipated.

This study is groundbreaking as it disputes the common narrative that such natural pregnancies are “miracle” pregnancies, and instead, emphasizes that they are not as rare as previously thought.

The researchers conducted a systematic review with meta-analysis, scrutinizing studies published from 1980 to September 24, 2021. The team searched Ovid Medline, Embase, and PsycINFO databases for studies in English, involving human subjects. The main criterion for inclusion was studies that measured the proportion of women experiencing natural conception following an ART live birth.

The team assessed the quality of the included studies using the Critical Appraisal Skills Programme cohort study checklist or the AXIS Appraisal tool for cross-sectional studies. Random-effects meta-analyses were utilized to estimate the pooled effect of the proportion of natural conception pregnancies after ART live births.

Out of 1108 distinct studies initially identified, 11 studies involving 5180 women were selected for the review. The maximum follow-up period in these studies ranged from 2 to 15 years. The pooled estimate for the proportion of women experiencing natural conception pregnancies after ART live birth stood at 20% (95% CI, 17-22%).

The study acknowledges several limitations, including variability in methodology, population, subfertility cause, type and outcome of fertility treatment, and follow-up duration among the studies considered. These variations might lead to potential biases related to confounding, selection bias, and missing data.

The study’s findings have wide-reaching implications, primarily in dispelling misconceptions surrounding natural conception post-ART. This knowledge is vital for healthcare professionals and couples who have undergone or are considering ART.

Recognizing the frequency of natural conception following ART, it becomes crucial to provide tailored counseling to couples contemplating further ART procedures.

Dr. Thwaites and her team advocate for national, data-linked studies to ascertain more accurate estimates and analyze factors associated with natural conception after ART. Such data would empower women and couples to make informed choices regarding family planning and further fertility treatments.

This research, supported by the National Institute for Health Research (NIHR) as part of an academic clinical fellowship awarded to Dr. Thwaites, is poised to transform perceptions and practices in the realm of reproductive science.

Sources and References

Human Reproduction - How common is natural conception in women who have had a livebirth via assisted reproductive technology? Systematic review and meta-analysis

BBC News - One in five chance of natural pregnancy after IVF baby

UCL News - One in five women become pregnant naturally after having a baby conceived with IVF